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  1. #1
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    Et tu, JET 9? Crankset clearance issues....

    Say it isn't so, but the same issues discovered and pounded over in the new RIP frame thread about XT and other crankset clearance issues with 42T+ plus rings raised its ugly head for me yesterday in an XC race in Minnesota.

    Here's the RIP thread I am making reference to.

    I'm running Race Face Turbine 180mm cranks with the 2 x 9 Rotor Q Rings 27/40. The 40T, based on the shape of it, sort of varies between 38 or 39T and 41 or 42T on its revolution depending on whether or not the shape is in the power stroke or not. So even though it is a 40T, it really requires about the same clearance as a 42T which, for the first time reared its ugly head yesterday for me in a race. The same exact chain situation as you see pictured in post #140 in the RIP thread is what kept happening to me in the race when running the chain on the 27T inner ring. Not chain suck, but chain stuck issues as the motion of the CVA rear triangle and action in the chain would cause it to jump up and get stuck between the chainstay and outer ring. I was off the bike trying to fix the chain no less than a dozen times yesterday which obviously took me out of the competitive racing department. The previous week I got 4th place on the RIP, but racing against the same group of Minnesotra guys I dropped to 8th place thanks to my chain clearance woes. I finally gave up in lap 2 and just kept it in the big ring which meant I had to walk the steepest hills.

    Like the RIP thread when the new RIP frame with the wider yoke in 2009 came out, this new wider yoke with the CVA design of the new JET seems to be similar. I had no problems whatsoever running the same 2 x 9 drivetrain on my old recalled JET, but I think it is now officially a no-go on the new JET. I'll have to come up with a different drivetrain and say good-bye to at least the 40T Rotor Q Ring since at it's widest point it is like a 42T.

    I would be curious if others have discovered this with their new JETs and the wider yoke - no matter what the drivetrain brand is. The work around for me on the RIP with the 44T ring was to get Bruzed's excellent 30/40T rings for the XT cranks and my RIP is now a smooth purring bike with no issues. I've got another set of XT cranks I could move over to the JET and get another set of Bruzed's rings if I want to go that route. Or I could even go 1 x 9 or 1 x 10, or invest in another crankset.

    Post up if you have incurred the wrath of the wider yoke chain stuck issue (again, see the pictures in post #140 of the RIP thread). Well, here - I'll just copy Drecastro's photos (if he doesn't mind) for the explanation of the issue. RIP or JET, it can happen.

    <a href="http://www.flickr.com/photos/7166535@N05/4765204388/" title="WideYokeRIP by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4073/4765204388_c894faf10f_o.jpg" width="453" height="604" alt="WideYokeRIP" /></a>

    <a href="http://www.flickr.com/photos/7166535@N05/4764568445/" title="YokeIssues by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4077/4764568445_6c132df259_o.jpg" width="604" height="453" alt="YokeIssues" /></a>

    <a href="http://www.flickr.com/photos/7166535@N05/4764568249/" title="WideYokeChainStuck by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4074/4764568249_cbddfb0e8c_b.jpg" width="604" height="453" alt="WideYokeChainStuck" /></a>

    BB

  2. #2
    Carbon & Ti rule
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    Thats no good.
    I'm putting the new 10 speed XT gear on 1 of my Rips the 10 speed XT crank is 24/32/42
    & running the 11/36 XT cassette.
    I have a 6 Berth Motorhome that I rent out . It is based in Tauranga, New Zealand

  3. #3
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    I have the new Jet and running the FSA 27/40 - have not had any issues as of yet. I used to ride a GF Cake that always had this problem. You can fix it pretty simply by adding a zip tie around the chain stay and place the head of the zip tie at the bottom where the chain would slap up in. I would run 2 of them criss crossed and then glue them together so they did not move.

  4. #4
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    Also while racing if you smash your butt down on the saddle without pedaling, it will open the gap and let the chain fall through, still a pain though, but you would not need to stop.

  5. #5
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    Quote Originally Posted by Spinning Lizard
    I have the new Jet and running the FSA 27/40 - have not had any issues as of yet. I used to ride a GF Cake that always had this problem. You can fix it pretty simply by adding a zip tie around the chain stay and place the head of the zip tie at the bottom where the chain would slap up in. I would run 2 of them criss crossed and then glue them together so they did not move.
    Thanks for the suggestion. I will try the zip ties.

    If they don't work, I think I need to do a permanent "fix" so I have peace of mind and can hammer without any worry. The 40T you have won't give you a problem. My 40T becomes a 42T at the largest point of the oval Rotor Q Ring which is where the problem occurs. If it was a normal round 40T (non Rotor Q Ring), I'd be fine. I may just dump the outer Rotor ring and pick up a standard 38, 39 or 40T ring that fits the BCD of the Turbines and forget about it.

    I wonder if anyone with a 42 or 44T outer ring is experiencing any issue with the wider yoke on the new JETs.

  6. #6
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    Mine did the same thing. Shortened the chain and the problem went away. I now can not use the 42/34 as the chain is to short I could use the 42/3?, next one down if I wanted to though.

  7. #7
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    Quote Originally Posted by Adrinln
    Mine did the same thing. Shortened the chain and the problem went away. I now can not use the 42/34 as the chain is to short I could use the 42/3?, next one down if I wanted to though.
    Chain is about as short as she blows, but I swapped out to a shorter Hollowpin one I had in the parts bin from last season (tried that chain on my RIP to no avail as well before swapping to smaller rings). I also put three zip ties with the heads strategically positioned to hopefully keep the chain from hopping up between the chainstay and outer ring when in the inner ring of my 2 x 9.

    It wouldn't be a problem if I was running normal 27/40T rings. It's just these oval shaped Q Rings have the largest part of the oval being about the same as a 42 or 43T ring and that's where it gets "stuck".

    I've got options.

    A. Get a longer spindle square taper BB to push the rings out a bit so there is plenty of clearance to prevent the "stuck" issue.

    B. Drop the outer Q ring and run a round 38 or 40T outer ring.

    C. Swap to one of my Middleburn Duo sets.

    D. Go triple with an older Shimano XT set I have using Bruzed's 30/40T middle and outer rings (or go 1 x 9 or 10 with a Widgit on the XT's).

    E. Buy an entirely new crankset that works on the JET.

    F. And many more....

  8. #8
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    I was having the same issue on my RIP but I then sized my chain per the SRAM chain sizing video and I've had zero problems. My friends were having the same problem with their RIPs and JETs and after I resized their chains the problem seems to have gone away.

  9. #9
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    Quote Originally Posted by bike29er
    I was having the same issue on my RIP but I then sized my chain per the SRAM chain sizing video and I've had zero problems. My friends were having the same problem with their RIPs and JETs and after I resized their chains the problem seems to have gone away.
    As in let the air out of the rear shock, wrap the chain around the big/big combo and add an inch? I tried that on the RIP with my Shimano XT triple 22/32/44 and it didn't work. I had to go to 30/40 middle and outer rings to achieve total success. I am assuming the same would work on the JET - at least with the XT crankset - as the wider yoke on the new JET seems to create a similar situation as the RIP frame.

    I've now got the chain dialed on the JET and zip ties in place. I cannot recreate the situation in the neighborhood (can't get out on the trails due to massive amounts of rain), but racing is a different thing where conditions create scenarios for problems to crop up. I'll probably take one of my other bikes to this weekend's race that I know has no shifting issues rather than risk the JET's current drivetrain setup that I have causing me grief without more testing and problem solving.

    BB

  10. #10
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    This happened to me on my 2nd ride with the new frame. XT cranks. Scratched the heck out of the chainstay.

    How exactly do you position the zip ties? Any pics?

  11. #11
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    only one ride thus far but I am running the truvativ 3.3 noir triple and it doesn't appear to be an issue, yet. I am removing the 44t and putting a noir carbon ring on in it's place, I don't use the big ring. I hope you get it sorted.
    Isaac

  12. #12
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    If your cranks/BB are set up properly the big ring should be out side of the chainstay/yoke. If you are having contact issues between the big ring and the chainstay yoke you are most likely not running the chainrings at the correct chainline position. Double check the installation of the crankset to make sure you have the proper spacers installed on the BB.

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  13. #13
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    Quote Originally Posted by Niner Bikes
    If your cranks/BB are set up properly the big ring should be out side of the chainstay/yoke. If you are having contact issues between the big ring and the chainstay yoke you are most likely not running the chainrings at the correct chainline position. Double check the installation of the crankset to make sure you have the proper spacers installed on the BB.

    Niner

    I can't speak for others, but my problem is the chain getting stuck between the big ring and chainstay/yoke. The big ring itself does not hit the chainstay/yoke.

  14. #14
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    Quote Originally Posted by Niner Bikes
    If your cranks/BB are set up properly the big ring should be out side of the chainstay/yoke. If you are having contact issues between the big ring and the chainstay yoke you are most likely not running the chainrings at the correct chainline position. Double check the installation of the crankset to make sure you have the proper spacers installed on the BB.

    Niner
    You are correct that enough space must be given so there is no contact between the big ring and the chainstay yoke. That would be a nasty metallic collision that would easily be heard in the first pedal stroke or two. In no experiments that I have tried has my big ring actually "hit" or "contacted" the yoke. Well, I did put the Middleburn Duo on there and realized it wasn't going to work with the Crank Brothers 113mm ISIS BB spindle length with the rings I had on it (29/42), so I yanked it. It is the clearance space issue (or the gap) between the big ring and yoke not being large enough to prevent the chain from getting stuck between the yoke and the outer ring - even if one's big ring is sitting out far enough to not have any contact with the chainstay yoke. I remember on the RIP thread, that a triple crankset with a 51mm chainline was good to go. The 47.5mm - 50mm chainline triples with larger outer rings (42 or 44T) were "not" good to go.

    I will, however, try a longer spindle BB today. The one I have in my parts bin will increase my Q Factor by a bit (I can try to make that up with cleat position or pedal spindle length), but it should give me 2-3mm more space in the gap. Unfortunately, it's going to cost me about 150 - 170 extra grams - but that's not a deal killer if I can get things working with this 2 x 9 and get rid of the chain stuck issues.

    See my diligent posts with all the chainline information in the RIP clearance issue thread. Lots of good posts regarding the spacers in that thread as well leading to the conclusion that correct chainline and spacers does not solve the issue - at least on the RIP and XT cranks. My guess from this developing thread and the experience I am going through is the same conclusion will be drawn for the JET by the time it is all said and done. That's not a bad thing, just one that needs to be brought to the fore. It's also very timely now that the industry is moving to what many of us have been running (MacGuyvering together, etc...) for a few years: 2 x 9 drivetrains. And now the 2 x 10 drivetrains that look to be replacing the age old triple mountain bike set up.

    So, it is pertinent for everyone to know what exactly does and doesn't work on both the RIP and the JET frames (I haven't followed anything with regard to the WFO and chainstay/yoke clearance, but I would Hammerschmidt that bike anyway ). We now know that Russ Anderson's (Bruzed) excellent 30/40T middle and outer rings solve the equation for XT cranks. Mine allow me to run a nice narrow Q factor. And it is very pertinent to know exactly what chainlines and size rings will work in the new 2 x 9/10 drivetrains. I believe 39T or less for the outer ring as a starting point. No way the 42T outer ring will work in a 2 x whatever drivetrain on the RIP or the JET.

    I run a 47.5mm chainline on the RIP with 20/30/40T rings on a Shimano XT M752 Hollowtech II crankset using a 113mm Octalink BB. The 118mm BB got the chainline to 50mm, but the 44T big ring was the stumbling block. It was all documented in the RIP thread about the process I went through with chainline, BB spindle length, ring size and the final solution. Now, I could go through the entire process with the same equipment on the JET and probably end up with the same issues which would lead me to proclaim - don't run anything over a 40T outer ring on the JET (just like the RIP) in a triple set up. However, I am not certain of that just yet and is why I asked about others who may be running 42 and 44T rings on their JETs to hear about experiences they are having (both positive and negative).

    Your suggestion of running the big ring all the way on the outside of the chainstay and yoke I assume is with regard to the actual outer ring not hitting the yoke or chainstay. As I said in the first sentence of this post - that isn't the issue. It is the gap between the outer ring and chainstay yoke that needs to increase to prevent the chain from getting stuck in there when running it in the smaller or middle ring (depending on if one is doing a triple or a double). If creating enough gap is the solution, it is going to call for a monster sized Q factor. I am assuming you mean all the way clear of the chainstay (but a picture would say a 1000 words and clear up any confusion as to exactly where you meant to run the big ring). Going with the chainstay as an example to clear - in terms of enough room for a chain to not get stuck in there - is going to require with the older XT cranks that one use the 126mm spindle length BB. Sorry for the BB spindle length talk, but I'm old school and have yet to "upgrade" to any outboard bearing set ups.

    And as Russ noted in the RIP thread, running such a wide chainline to take care of one problem might exacerbate another problem - actual chain suck (different from the chain "stuck" issue we are discussing here where the chain when run in the middle ring jumps up between the chainstay and outer ring to get stuck and scratch the bejeezus out of our yokes). Whether we are talking BB spindle lengths or amount of spacers to dial in the "correct" chainline - that doesn't remove the issue of what actual size outer chainring works problem free on the JET and RIP so that no chain "stuck" issues occur.

    I'll go out and take pictures this morning to show my chewed up yoke and my current attempt at a solution with zip ties and my MacGuyvered Race Face Turbine 2 x 9 with the duo Rotor Q Rings. And, I am using a 110mm spindle length Race Face Taplerlock BB with the thing pushed way over to the right to keep the outer ring away from the chainstay and yoke area. But I'll swap out to an older Shimano BB with a 122 or 124mm to see what that does. The Taperlock spindle length doesn't quite translate to the Shimano due to the way the Taper works (basically, a shorter spindle on a Taperlock of 110mm is probably more equivalent to 118mm or so in other brands). So the Shimano BB I have will probably net me an extra 2mm or so. I'll take pictures and report back.

    Now, if I can just convince Rotor to make a 38T or 39T outer ring for the new 2 x 10 set ups...

    BB

    P.S. No single speeders need reply...
    Last edited by BruceBrown; 07-09-2010 at 09:42 AM.

  15. #15
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    Okay, so I went out to swap BB's from my Taperlock Ti 110mm spindle (which weighs a svelte 166 grams) to a very old Shimano square taper boat anchor that was 122mm in spindle length and weighed well over 300 grams [OUCH!!!]. But, lighter ones are available - so there is hope (hello Phil Wood 123mm JIS Ti or White Industries 121mm). I just happened to have it in my parts bin from a 1989 Trek mountain bike.

    Q - Factor with the Taperlock = 168mm
    Q - Factor with the Shimano = 171mm

    So I didn't gain much in clearance space, but 1.5mm is 1.5mm.

    Photographs didn't turn out too well, but here they are.

    Clearance in the gap at the smaller portion of the outer 40T Q Ring (remember, this is an oval ring, so the narrow portion of the oval is about a 38T):

    <a href="http://www.flickr.com/photos/7166535@N05/4777768970/" title="JET's Clearance by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4139/4777768970_489270cb4c_b.jpg" width="1024" height="666" alt="JET's Clearance " /></a>

    <a href="http://www.flickr.com/photos/7166535@N05/4777133891/" title="Taperlock BB smaller portion of ring by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4094/4777133891_2f26b6bc27_b.jpg" width="1024" height="768" alt="Taperlock BB smaller portion of ring" /></a>

    Clearance in the gap at the larger portion of the outer 40T Q Ring (it's about a 42T at this point):

    <a href="http://www.flickr.com/photos/7166535@N05/4777768314/" title="Taperlock BB larger portion of ring by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4096/4777768314_1e3aa816b0_b.jpg" width="1024" height="608" alt="Taperlock BB larger portion of ring" /></a>

    Bike flipped upside donw to show the yoke damage from the stuck chain syndrome and my army of Zip Tie heads which Spinning Lizard suggested I try:

    <a href="http://www.flickr.com/photos/7166535@N05/4777767728/" title="Yoke Damange and Zip Tie Parage by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4123/4777767728_0f21436f7f_b.jpg" width="1024" height="768" alt="Yoke Damange and Zip Tie Parage" /></a>

    In contrast, look at the beautiful clearance on the RIP with Bruzed's 40T outer ring for the Shimano XT crankset. I'm running it with a 47.5mm chainline and 171mm Q-Factor. Plenty of gap space, plus the nice notch that Niner put in the frame to prevent any chain stuck from taking place.

    <a href="http://www.flickr.com/photos/7166535@N05/4777132751/" title="40T Clearance on RIP - beautiful clearance by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4122/4777132751_6973b82f1f_b.jpg" width="1024" height="619" alt="40T Clearance on RIP - beautiful clearance" /></a>

    <a href="http://www.flickr.com/photos/7166535@N05/4777132751/" title="40T Clearance on RIP - beautiful clearance by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4122/4777132751_6973b82f1f_b.jpg" width="1024" height="619" alt="40T Clearance on RIP - beautiful clearance" /></a>

    Now here is the JET with the longer spindle Shimano boat anchor BB. I gained a bit of clearance in the gap, but is it enough?

    <a href="http://www.flickr.com/photos/7166535@N05/4777131849/" title="JET Clearance by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4121/4777131849_673edbe545_b.jpg" width="1024" height="853" alt="JET Clearance" /></a>

    <a href="http://www.flickr.com/photos/7166535@N05/4777766702/" title="JET Clearance by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4115/4777766702_08ce8ea358_b.jpg" width="1024" height="768" alt="JET Clearance" /></a>

    Not as much gap space as I would like to have (such as the 40T on the RIP), but it is a bit better than before and the Q-Factor didn't grow too much. Call it an additional 1.5mm - maybe 2mm than with the Taperlock. Enough additional sticking out on the right side that I had to mod my Dura Ace front derailleur to be able to reach out far enough to the outer ring. Thanks Dremel!

    Heck, after all of that - I could have just pushed my Taperlock out to the right another 1.5mm or so and kept the lighter weight. But it was already pushed over to the right quite a bit and any more was going to require some serious cleat adjustments to make it all square again for my legs once I was on the bike. It's still an option...

    I'm probably a perfect candidate for the XX drivetrain since it comes in multiple Q - Factor options. But I will let others spend the dough on ironing that out on the JET first before I pony up that kind of cash. Certainly, the 39T max for the outer ring.

    I was unable to recreate any stuck chain in the neighborhood after the BB swap. However, I wasn't able to create it with the narrower Taperlock BB either. It only cropped up during a race under tremendous climbing pressure. I will take it out for a spin this afternoon, but I can't ride in the dirt due to the wet conditions we have. So it will have to wait for the WORS race this weekend if I take the JET. My gut says take a different bike until this is ironed out and problem free, but I love to race on the JET....

    Does the JET frame need the "notch" that Niner added to the RIP after early reports of chains getting stuck in there?

    BB
    Last edited by BruceBrown; 07-09-2010 at 01:01 PM.

  16. #16
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    Hey Bruce,

    There's kind of a lot going on here, so I'll try to address this the best way I can with the information you've given. It looks like the MAIN issue here is that you're running the large chainring in the middle chainring position. We've designed the Jet 9 to work with standard triple chainring configurations, as well as SRAM and SHIMANO's 2x10 gearing. With the Sram (and Shimano, which put the chainrings in almost the same position), the outer ring is a tad inboard of a standard outer ring, but it's also a round 39t. It's still not as far inboard as a middle chainring from a triple crank. What I would suggest is going back to your 110mm BB and running your chainring in the outer position and middle position respectively. The other issue you will obviously have to deal with is your inner chainring, which is on the 74mm bolt pattern of your Race Face cranks. I understand that you can't have one ring in the outer position, and one in the inner and skip the middle position. I couldn't tell from your posts what you're running for a small chainring, but I think the 110/74 bolt pattern you're using is a little prohibitive for the setup you're trying to go for. This is a difficult situation, but it seems like with the equipment you're working with, it will be difficult to get the clearance you need. I hope this helps.

    Steve
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    Last edited by Niner Bikes; 07-09-2010 at 04:30 PM.
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  17. #17
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    Quote Originally Posted by Niner Bikes
    Just so it is clear, you can easily run a 44 tooth chainring on the JET 9 frame when set up properly. There is plenty of clearance for a standard 22/32/44 crank set. You are running a 40 tooth chainring in the middle position, hence you are experiencing clearance issues.


    Niner
    Yes, my outer ring is bolted in the middle position (for those not in the know - that's standard fare when running Rotor Q Rings on Race Face 110/74 BCD Turbines or any other 110/74 BCD crank arms), but it is pushed out to the right into the position of a standard 2 x 9/10 configuration for chainline (matches exactly the chainline of the purpose built Middleburn Duo). In other words, the crankset is not pulled in all the way to where the middle and granny ring sit on a triple by any means. It's way right.

    So, assuming a lot of racers and riders who purchase the JET for racing may want to run the XX or upcoming 2 x 10 drivetrains of X.0, X.9, etc... or those from Shimano I feel that it is indeed pertinent to look at the clearance issues of the JET. As those 2 x 10's will indeed become industry standard as we say good-bye to triples (welcome to forced technology adoption life cycles), mount up 11-36 rear cassettes and marvel at how a 2 x 10 pretty much covers all the bases that a triple used to cover.

    I haven't tried it yet, but based on my measurements and fiddling with the RIP and JET, I bet the only way to run a Shimano triple XT with a 44T ring would be to take the Q factor to a minimum of 175mm which is not going to tickle any XC racer's fancy at that kind of width. Can we say inner knee pain? XX 2 x 10's offer the choice of Q-factors being 156mm, 164mm and 166mm.

    I'd like to see those XX duo rings of 26/39T with the 156mm Q-Factor on a JET working cleanly with no chain stuck issues.

    I'll stand corrected if they do work without a hitch.

    Anyway, love the frame. Hate the clearance issues of the RIP and JET in terms of drive train issues. Maybe more will post with positive (and negative) experiences so we can get a good read on the real situation.

    BB

  18. #18
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    Quote Originally Posted by Niner Bikes
    Hey Bruce,

    There's kind of a lot going on here, so I'll try to address this the best way I can with the information you've given. It looks like the MAIN issue here is that you're running the large chainring in the middle chainring position. We've designed the Jet 9 to work with standard triple chainring configurations, as well as SRAM and SHIMANO's 2x10 gearing. With the Sram (and Shimano, which put the chainrings in almost the same position), the outer ring is a tad inboard of a standard outer ring, but it's also a round 39t. It's still not as far inboard as a middle chainring from a triple crank. What I would suggest is going back to your 110mm BB and running your chainring in the outer position and middle position respectively. The other issue you will obviously have to deal with is your inner chainring, which is on the 74mm bolt pattern of your Race Face cranks. I understand that you can't have one ring in the outer position, and one in the inner and skip the middle position. I couldn't tell from your posts what you're running for a small chainring, but I think the 110/74 bolt pattern you're using is a little prohibitive for the setup you're trying to go for. This is a difficult situation, but it seems like with the equipment you're working with, it will be difficult to get the clearance you need. I hope this helps.

    Steve
    Niner Bikes
    I certainly did not mince my words about my situation having a lot going on due to my Rotor Q Rings on an older Race Face Turbine crankset - that's for sure. I should have made it a lot easier and just mounted up my Hollowtech II XT rings 22/32/44 with the appropriate 68mm X 113mm Octalink BB to show that chain stuck occurs on the JET just like it does on the RIP. That would've been easier and made this thread parallel the RIP XT clearance issue thread.

    But, back to my "lot going on here" situation....

    Yes, the Rotor 2 x 9/10 rings only come in the 74mm and 110mm BCD pattern. Small ring goes on the 74 granny spot, and the outer ring runs in the slot of a middle (unless you buy the Rotor 2 x 9/10 specific crankset which doesn't come longer than 175mm crank arms. I run the Turbines at 180mm and I can't move the rings out to the middle/outer postions and go back to the 110mm spindle BB.

    There were no clearance issues on the prior version of the JET with my set up as the chainstay yoke was not as wide as the new frame's chainstay yoke. I can see where a 38 or 39T round ring would be the ticket for a 2 x 9/10 crankset running the rings in the traditional chainline for a double (granny is slightly out from a triple and the outer ring is slightly in from the outer ring on a triple). And you guys have already stated from Niner on this forum that the JET will not have enough clearance for the XX 2 x 10 rings in the 28/42T size. Just the 26/39.

    I guess my MAIN issue is that my 2 x 9 worked fine and dandy on the old JET, but not on the new JET without some changes. Ah....the price of forward progress.

    I'm quasi-cool with that because I know you had to make changes to the design to improve what was going wrong with it before. I'm just trying to report the clearance issues and possible workarounds that come up (which are very similar and remind me a lot of the RIP thread when it was discovered chain stuck issues were happening). That's why I started this thread. I've discovered I cannot run the rings in the traditional 2 x 9 chainline like I did before on the JET (copied the Middleburn Duo chainline to a T) or like I do on my other bikes with the Middleburn Duo's (Salsa Dos Niner and Niner Air 9). But today's swap to a 122mm spindle length seems to be a positive step in the right direction of getting my favorite 2 x 9 Rotor Q Rings to function on this bike. I think my knees can live with the slightly wider Q Factor if it means no chain stuck. That and my army of zip ties down there to fight that chain when it is in the small ring.

    Now if I wanted to stick with the excellent Rotor Q Rings and decided to go back to a triple - the triple Rotor Q rings can be had in the 104/64mm and XTR patterns. However, the large ring of the Rotor Q Rings for a triple is bigger than 44T. I believe it is a 46T (which means in the power portion of that oval ring it would be like a 48T ring) which is a heck of a lot more than I would use during a typical XC race. And I can imagine the clearance issues, amount of spacers, width of bottom bracket spindle, etc.... that would be required to get that to work if I ran those on my current XT cranks (Hollowtech II which requires an Octalink BB).

    However, those XT cranks did not work on the RIP with the properly set up bottom bracket and standard 22/32/44 rings (Octalink 113mm 73mm BB - nor did they work with the 118mm x 73mm BB) and is what led me to get Bruzed's 30/40T rings to replace the 32/44T middle and outer rings. Now it is perfect with no chain stuck issues and I know would work perfectly on the JET as well with the 22/30/40 rings if I chose to go that route (and use the 68mm shell BB of course).

    I'm pretty sure my 2 current sets XT Hollowtech II cranks with their original 22/32/44 rings and the traditional Octalink 68mm X 113mm spindle would not work on the JET due to the clearance issues (same problem that the RIP had). I think it would only fit with the 126mm spindle (which would be a Q Factor of 183.8mm (getting DH wide), and would hopefully be pushed out enough to rid all chain stuck clearance issues.

    As I said - I know I am running a set up that is "off the beaten path". Middleburn suggests a 113mm BB spindle length for their Duo. I've got a 110/74mm spider for the Middleburn crank arms that would allow me to run my Rotor Q Rings, but I would face the same clearance issues and need a longer BB. If one decides to run the Middleburn Duo cranks on the JET, I would propose that one drop down to their new 27/38T Duo ring combo (Mountain Bike Tandems sells them) with that spindle length BB.

    You mentioned the SRAM XX in the 26/39T fits on the JET. Do you know if all 3 Q - Factor options fit on the JET? (156mm, 164mm and 166mm)

    I will report back as to how the 122mm spindle works as I get more time on the JET with it. Luckily, Phil Wood and White Industries both have square taper BB's around that length that are weight weenie material like my 166g Taperlock BB.

    Hopefully, others will post positive and negative experiences simply as an information collecting thread like the RIP thread which was very informative and led to a real world problem solving development of Russ Anderson's 30/40T middle and outer rings.

    BB

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    Bruce,

    I'm trying to help, and I apologize if something got lost in translation. The fact is, we can't possibly design around every configuration possible on a bike, and we've done the best we can using the configurations we can account for. The new Jet 9 chainstay yoke was one of the key elements to increasing stiffness on the rear triangle, which was one of the design goals with the re-design. We haven't heard of any issues out there on the trail, and there are a lot of people running XX 2x10 (I've run it myself on the frame with no issues at all, in both the 42/28 and the 39/26). The different Q factors of XX cranks do not change the position of the chainrings, only the crank arm bend coming out of the chainrings. The chainring clearance is the same for all Q factor cranks. I've attached a pic of the clearance that the 39/26 XX cranks have.

    I'm really sorry that you're having issues with your new frame on this matter. We obviously looked at the chainsuck issues from the RIP 9 before building the new Jet, and even prototyped the chainstay yoke to insure that this wouldn't be an issue.

    Steve
    Niner Bikes
    Attached Thumbnails Attached Thumbnails Et tu, JET 9?  Crankset clearance issues....-jet-9-sram-xx-cranks-clearance-small.jpg  

    .........

    Peace,
    Niner Bikes

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  20. #20
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    Quote Originally Posted by Niner Bikes
    Bruce,

    I'm trying to help, and I apologize if something got lost in translation. The fact is, we can't possibly design around every configuration possible on a bike, and we've done the best we can using the configurations we can account for. The new Jet 9 chainstay yoke was one of the key elements to increasing stiffness on the rear triangle, which was one of the design goals with the re-design. We haven't heard of any issues out there on the trail, and there are a lot of people running XX 2x10 (I've run it myself on the frame with no issues at all, in both the 42/28 and the 39/26). The different Q factors of XX cranks do not change the position of the chainrings, only the crank arm bend coming out of the chainrings. The chainring clearance is the same for all Q factor cranks. I've attached a pic of the clearance that the 39/26 XX cranks have.

    I'm really sorry that you're having issues with your new frame on this matter. We obviously looked at the chainsuck issues from the RIP 9 before building the new Jet, and even prototyped the chainstay yoke to insure that this wouldn't be an issue.

    Steve
    Niner Bikes
    I know you are trying to help and I appreciate it. I think I'm about solved with the longer BB spindle and "insurance Zip Ties below" for now.

    Yummy - those XX's look like the perfect ticket for a 2 x 10 with the clearance in that photo. Now, as soon as SRAM starts making them in 180mm arm lengths.....

    BB

    P.S. Is that a little notch in the yoke I see in the supplied picture?

  21. #21
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    Important Update: I now have 2 successful XC races on the new JET 9 with absolutely no chain "stuck" issues. Moving from the 110mm Race Face Taperlock bottom bracket (which worked perfectly on the recalled JET) to a Shimano 122mm spindle length has given me enough clearance for my 2 x 9 Rotor Q Rings on the Race Face Turbines to work like they did before.

    Those Shimano BB's are serious work horses (should be for the boat anchor weight the are), but I wanted to try it out before investing in a weight weenie White Industries, Phil Wood or whatever to challenge the 166g weight of the Taperlock I had to give up.

    What does the Shimano 122mm spindle mean in terms of my 2 x 9 chainline. Remember, the golden benchmark 2 x 9 or 2 x 10 chainline is 48 mm. That is the Middleburn Duo standard and allows you to use every single gear on the rear cassette with each of the Duo rings up front. 2 x 9/10 chainline is a slightly different measurement than a triple crankset. The 2 x 9/10 chainline is the distance from the middle of the seat tube to the exact midpoint between the outer and inner rings where as the triple chainline measurement is the number of mm's from the center of the seat tube to the middle of the middle chainring.

    Here are the measurements on my set up (Race Face 180mm Turbines, Rotor Q Rings 27T inner and 40T outer, Shimano square taper 122mm spindle Bottom Bracket):

    70.5mm measurement (outer side of seat tube to middle of outer chainring)
    60.5mm measurement (outer side of seat tube to middle of inner chainring)
    35mm (width of seat tube)

    70.5 - 17.5 + 60.5 - 17.5 = 96/2 = 48mm!!!!!

    Pay dirt!

    Although the Race Face Taperlock 110mm spindle bottom bracket was able to give me the correct chainline on the recalled JET 9 (I did move the Taperlock a couple of thread to the right to accomplish this) and provide a nice Q Factor - it does not work on the new JET 9 due to the wider chainstay yoke are (needed and welcomed to improve rear end stiffness). The 122mm spindle does the trick, gets me back to a perfect chainline and does not create any of the dreaded chain "stuck" issue.

    I may need to do a little touch up paint of the areas I chewed up in working through all of this, but I am happy to report success has been achieved.

    And I will echo Steve's words of wisdom from Niner - as long as things are set up properly, the chainsuck should not be an issue. It obviously took me a bit of experimentation to achieve the "properly" portion of set up.

    I am not totally in love with my new JET as it has shifted flawlessly under the intense pressure of 2 XC races (a third one coming tomorrow).

    I do wish mine had that notch cut out like the one Steve shows above, but here's a picture from post race today with the "new" clearance (zip ties still there for insurance):

    <a href="http://www.flickr.com/photos/7166535@N05/4802772403/" title="Shimano 122mm spindle by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4135/4802772403_c4895ef4d1_b.jpg" width="1024" height="547" alt="Shimano 122mm spindle" /></a>



    BB

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    Quote Originally Posted by BruceBrown

    And I will echo Steve's words of wisdom from Niner - as long as things are set up properly, the chainsuck should not be an issue. It obviously took me a bit of experimentation to achieve the "properly" portion of set up.



    BB
    I wish I could figure out what is going on with my bike then. My chain jammed between the outside chainring and chainstay yoke for the 3rd time in 5 rides this past weekend. I can get the chain back out by hand, but it is really chewing up the chain stay when it happens. I am riding in the middle chain ring each time it happens.

    I have an XT crankset with standard ring configuration, XTR bb, 2 spacers on the drive side and one on the non-drive side.


  23. #23
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    Quote Originally Posted by threefive
    I wish I could figure out what is going on with my bike then. My chain jammed between the outside chainring and chainstay yoke for the 3rd time in 5 rides this past weekend. I can get the chain back out by hand, but it is really chewing up the chain stay when it happens. I am riding in the middle chain ring each time it happens.

    I have an XT crankset with standard ring configuration, XTR bb, 2 spacers on the drive side and one on the non-drive side.

    Thanks for posting. That's why I started the thread.

    You are certainly a candidate for the 30/40 middle and outer rings from Bruzed that were designed for the XT crankset to work on the RIP (and I guess now JET) if the spacers do not take care of the situation.

    BB

  24. #24
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    The new 10 speed XT cranks are 24/32/42 & will work great to.
    I have a 6 Berth Motorhome that I rent out . It is based in Tauranga, New Zealand

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    Quote Originally Posted by muzzanic
    The new 10 speed XT cranks are 24/32/42 & will work great to.
    Will a 42 outer ring provide enough clearance? I don't want to change from the 32 in the middle, but I guess I can try a 42 on the outside. I'm going to try the zip ties next since they are cheaper than a chain ring! New cranks are certainly not in the budget right now. I have about a month to try to get this sorted before my next race.

  26. #26
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    Quote Originally Posted by Niner Bikes
    Bruce,

    I'm trying to help, and I apologize if something got lost in translation. The fact is, we can't possibly design around every configuration possible on a bike, and we've done the best we can using the configurations we can account for. The new Jet 9 chainstay yoke was one of the key elements to increasing stiffness on the rear triangle, which was one of the design goals with the re-design. We haven't heard of any issues out there on the trail, and there are a lot of people running XX 2x10 (I've run it myself on the frame with no issues at all, in both the 42/28 and the 39/26). The different Q factors of XX cranks do not change the position of the chainrings, only the crank arm bend coming out of the chainrings. The chainring clearance is the same for all Q factor cranks. I've attached a pic of the clearance that the 39/26 XX cranks have.

    I'm really sorry that you're having issues with your new frame on this matter. We obviously looked at the chainsuck issues from the RIP 9 before building the new Jet, and even prototyped the chainstay yoke to insure that this wouldn't be an issue.

    Steve
    Niner Bikes
    We need to update Steve's comment here in bold above...and list what Niner says on the JET 9 website under the SPECIFICATIONS & COMPATIBILITY:

    Compatible with 2x systems from SRAM and SHIMANO, however certain gear sizes will not fit:

    * SRAM recommended 2x front chainring configs: 26/39 or lower
    * SHIMANO recommended 2x front chainring configs: 28/40

    So, although Steve had ridden the SRAM XX with the 42T outer ring and claimed no issues at all on his JET, Niner recommends you run 26/39 or lower for the SRAM 2 x rings. Based on my experience of running a 2 x system with the exact correct chainline for a 2 x - I concur.

    BB
    Last edited by BruceBrown; 01-27-2011 at 03:00 AM.

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    Niner hasn't changed anything, their spec has always been to use the 26/39 chainring combo on all of their bikes. Steve was simply saying that he personally has used the larger chainring option with out issues.

    You have a funky set up and it took some effort to make it work right. That is what it takes to run a funky set up. The Jet works great with 2x10 or a standard 3x9/10. It seems like you feel there is a design flaw with the JET and I don't understand why.

  28. #28
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    Quote Originally Posted by whydomylegshurt?
    Niner hasn't changed anything, their spec has always been to use the 26/39 chainring combo on all of their bikes. Steve was simply saying that he personally has used the larger chainring option with out issues.

    You have a funky set up and it took some effort to make it work right. That is what it takes to run a funky set up. The Jet works great with 2x10 or a standard 3x9/10. It seems like you feel there is a design flaw with the JET and I don't understand why.
    2 x drivetrains (and yes, purpose built Duo cranksets) have been around a lot longer than the new SRAM and Shimano 2 x products. When I bought my wife's Air 9, there was no spec saying 26/39 chainring combo on the Air 9 page at the Niner site. That is a new addition.

    I am not saying that there is a design flaw in the JET and the RIP. I am saying that the new chainstay/yoke design which improves stiffness over the previous generation models resulted in an increased chainline requirement for the larger rings to clear - and/or to prevent the chain from geting "stuck" when using the small ring on a 2 x drive train and it hops up between yoke and ring with an active suspension. It is what it is. That was not a problem on the prior generation JET 9.

    Why is Niner not saying or recommending to "go ahead and use a 42 ring on the JET" for the XX and Shimano 2 x duo ring cranksets?

    Actually they did say it:

    however certain gear sizes will not fit

    Yes, the Rotor Q Rings on Turbine cranks are "funky". However, I have them set up exactly like a purpose built Duo 2 x crankset (explained earlier in this thread).

    If I throw a standard Middleburn Duo crankset which is purpose built (I've got two sets of them) with their recommended chainline for a Duo (calls for a 113mm BB spindle to get the 48mm chainline) and use the 42 Ring, it does not clear when using the recommended BB for a proper 2 x 9/10 chainline. The ring rubs on the chainstay yoke of the JET. And if I push the BB spindle out to the right with spacers or adjustable chainline BB, the chain gets stuck when it hops up between the yoke and the big ring. Yet, a longer spindle BB and Zip Ties did solve my issue with the MacGyvered Rotor Q Rings/Race Face Turbine cranks for me.

    I did not have this problem on all other 29"er bikes I've used these Duo rings on with the recommended 48mm chainline (Niner Air 9, Salsa Dos Niner, Surly Karate Monkey, Gary Fisher Sugar 292/3). Now, if I use the 40T Duo ring - there is no issue of rub. But I would probably drop down to Middleburn's new 38T outer ring to avoid all issues of possible chain stuck from the hopping chain during hammer efforts in the inner ring if I were going to run the Middleburn Duo on my JET (or RIP).

    I'm not trying to point out a "flaw", but help people address the issue and who are looking to purchase a JET or a RIP. That was never mentioned in this thread back when Steve from Niner was posting. He said that he personally had "no issues" using the XX with a 42T outer ring. The Niner website has the information/recommendation of not going above the 39T with the XX. So my previous post was to point that out as "interesting" and supporting their decision to recommend that on the website.

    There have been quite a few posts on the 29"er forum with regard to this issue - the latest being a post asking for a definitive answer on whether or not his Shimano XT crankset with a 44T outer ring would fit/work okay on the JET. And since the XX came out, there have been several posts asking whether or not the XX with 42T would fit and work okay on a JET. So I dug up this thread again in hopes of others seeing it who are asking those questions - be it a double or a triple crankset they are considering or having difficulties with on the JET.

    I've been using a 2 x drivetrain for at least 5 years and am happy to see more products being offered in that category besides the Middleburn Duo, FSA, Extralite, TA Carmina, White Industries VBC, etc....and the MacGyvered It versions. And if I were purchasing a XX or Shimano 2 x 10 drivetrain - I would follow Niner's recommended comments about staying at 39T on the XX and 40T on the Shimano as the largest rings.

    BB
    Last edited by BruceBrown; 01-27-2011 at 03:05 AM.

  29. #29
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    Quote Originally Posted by whydomylegshurt?
    You have a funky set up and it took some effort to make it work right. That is what it takes to run a funky set up. The Jet works great with 2x10 or a standard 3x9/10. It seems like you feel there is a design flaw with the JET and I don't understand why.
    +1

    We don't use Netscape 2.o to surf the internet and wonder why none of the websites work...

    Bruce, you are in the exciting position of being able to benefit from 15 years of BB improvement, skip the hiccup of ISIS and go straight to 2006!

  30. #30
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    Quote Originally Posted by JMH
    +1

    We don't use Netscape 2.o to surf the internet and wonder why none of the websites work...

    Bruce, you are in the exciting position of being able to benefit from 15 years of BB improvement, skip the hiccup of ISIS and go straight to 2006!
    Uhhhh.....I don't use ISIS on the JET. I use square taper. But I do use Octalink on my RIP.

    Yes, I kind of have my eye on the new 2 x 10 drivetrains from SRAM, but prefer 180mm crank arms. And I was running 2 x 9 drivetrains for quite a few years on my 29"ers for racing before SRAM and Shimano came out with 2 x drivetrains and labeled it as "modern technology". So I guess I was ahead of the curve thanks to the British and their excellent Middleburn Duo cranksets.

    Then again, I use Avid BB7's on all of my bikes.

    BB
    Last edited by BruceBrown; 01-27-2011 at 02:59 AM.

  31. #31
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    Quote Originally Posted by BruceBrown
    Say it isn't so, but the same issues discovered and pounded over in the new RIP frame thread about XT and other crankset clearance issues with 42T+ plus rings raised its ugly head for me yesterday in an XC race in Minnesota.

    Here's the RIP thread I am making reference to.

    I'm running Race Face Turbine 180mm cranks with the 2 x 9 Rotor Q Rings 27/40. The 40T, based on the shape of it, sort of varies between 38 or 39T and 41 or 42T on its revolution depending on whether or not the shape is in the power stroke or not. So even though it is a 40T, it really requires about the same clearance as a 42T which, for the first time reared its ugly head yesterday for me in a race. The same exact chain situation as you see pictured in post #140 in the RIP thread is what kept happening to me in the race when running the chain on the 27T inner ring. Not chain suck, but chain stuck issues as the motion of the CVA rear triangle and action in the chain would cause it to jump up and get stuck between the chainstay and outer ring. I was off the bike trying to fix the chain no less than a dozen times yesterday which obviously took me out of the competitive racing department. The previous week I got 4th place on the RIP, but racing against the same group of Minnesotra guys I dropped to 8th place thanks to my chain clearance woes. I finally gave up in lap 2 and just kept it in the big ring which meant I had to walk the steepest hills.

    Like the RIP thread when the new RIP frame with the wider yoke in 2009 came out, this new wider yoke with the CVA design of the new JET seems to be similar. I had no problems whatsoever running the same 2 x 9 drivetrain on my old recalled JET, but I think it is now officially a no-go on the new JET. I'll have to come up with a different drivetrain and say good-bye to at least the 40T Rotor Q Ring since at it's widest point it is like a 42T.

    I would be curious if others have discovered this with their new JETs and the wider yoke - no matter what the drivetrain brand is. The work around for me on the RIP with the 44T ring was to get Bruzed's excellent 30/40T rings for the XT cranks and my RIP is now a smooth purring bike with no issues. I've got another set of XT cranks I could move over to the JET and get another set of Bruzed's rings if I want to go that route. Or I could even go 1 x 9 or 1 x 10, or invest in another crankset.

    Post up if you have incurred the wrath of the wider yoke chain stuck issue (again, see the pictures in post #140 of the RIP thread). Well, here - I'll just copy Drecastro's photos (if he doesn't mind) for the explanation of the issue. RIP or JET, it can happen.

    <a href="http://www.flickr.com/photos/7166535@N05/4765204388/" title="WideYokeRIP by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4073/4765204388_c894faf10f_o.jpg" width="453" height="604" alt="WideYokeRIP" /></a>

    <a href="http://www.flickr.com/photos/7166535@N05/4764568445/" title="YokeIssues by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4077/4764568445_6c132df259_o.jpg" width="604" height="453" alt="YokeIssues" /></a>

    <a href="http://www.flickr.com/photos/7166535@N05/4764568249/" title="WideYokeChainStuck by singingsingletracker, on Flickr"><img src="http://farm5.static.flickr.com/4074/4764568249_cbddfb0e8c_b.jpg" width="604" height="453" alt="WideYokeChainStuck" /></a>

    BB
    I have had this exact same thing happen on both the RIP 9 and Jet 9. I am running XTR 970 triple cranks on both of them. Doesn't happen often, but when it does it sometimes gets stuck. So what is the best solution to this? The zip ties in place to keep the chain from riding up?

  32. #32
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    Quote Originally Posted by epiphreddy
    I have had this exact same thing happen on both the RIP 9 and Jet 9. I am running XTR 970 triple cranks on both of them. Doesn't happen often, but when it does it sometimes gets stuck. So what is the best solution to this? The zip ties in place to keep the chain from riding up?
    epiphreddy, 44T Ring?
    .. If I see this bike on display with those GT bars, I am bringing my hacksaw!!

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    Yes, 44T Chain ring on both bikes.

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    I had this same thing happen again yesterday. This time in the granny gear however I was able to back pedal and it dropped right back down. My chain rings are practically new and my chain is new (as of yesterday). The conditions were somewhat muddy here and there. I can only assume this was due to chain suck. I always use a wax type lubricant. Should I be using a petroleum based lubricant for these types of conditions?

  35. #35
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    Quote Originally Posted by epiphreddy
    I had this same thing happen again yesterday. This time in the granny gear however I was able to back pedal and it dropped right back down. My chain rings are practically new and my chain is new (as of yesterday). The conditions were somewhat muddy here and there. I can only assume this was due to chain suck. I always use a wax type lubricant. Should I be using a petroleum based lubricant for these types of conditions?
    I'd venture to guess that it has nothing to do with traditional chain suck or what kind of lube you are or are not using.

    It's the bouncing of the chain as the suspension is active and the chain hops up between the large ring and the chainstay/yoke area (as pictured above). No amount of lube or brand new drivetrain parts will take care of this. Call the dilemma chain stuck, rather than a traditional chain suck.

    Clearance between the outer ring and the chainstay/yoke area is what will take care of it. That may mean pushing your XTR driveside crankarm out to the right a bit more (if you can), or it may mean getting a smaller outer ring (if you can't push the driveside out any more than it already is). How much smaller of a outer ring? Small enough that there is enough of a gap between the ring and the chainstay/yoke area that even if the chain does bounce up there it won't get stuck. A 40T solved that for me on the RIP and pushing my rings/arm out enough to the right on the JET solved mine (along with the zip ties).

    Post up a picture of the clearance on your RIP and JET between the XTR outer ring and the chainstay.

    BB

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    So how would you push the ring out further? Washers between the chainring and crankarms? Or another BB spacer on the right side????
    I emailed Niner and their response was that it was chain suck due to probably old rings or chain which cannot be the case because they are practically new. I am going to try the zip tie's and also some different "wet" lube anyways since I probably need to do that anyways due to the wet/muddy riding conditions.

  37. #37
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    Quote Originally Posted by epiphreddy
    So how would you push the ring out further? Washers between the chainring and crankarms? Or another BB spacer on the right side????
    I emailed Niner and their response was that it was chain suck due to probably old rings or chain which cannot be the case because they are practically new. I am going to try the zip tie's and also some different "wet" lube anyways since I probably need to do that anyways due to the wet/muddy riding conditions.
    I would imagine the spacers on the right side, but how many do you currently have on the drive side?

    I don't want to start sounding like LyNx, but if that was the response from Niner.....hmmmm.

    Post up a picture of the clearance you have (or don't have) between your 44T ring and the chainstay.

  38. #38
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    <a href="http://www.flickr.com/photos/7166535@N05/5390124673/" title="XX measurement specs by singingsingletracker, on Flickr"><img src="http://farm6.static.flickr.com/5052/5390124673_8265c70abf_b.jpg" width="732" height="548" alt="XX measurement specs" /></a>

    This file shows the clearance specs of the XX double cranksets, but if somebody really wanted to figure it all out, they could measure the L2 and L3 measurements on the JET (and RIP) frames to see what the maximum clearance would be from the center of the BB and use that to figure ring size and clearance when choosing and figuring if your cranks would or would not work on the frame. Ditto on adding another measurement for an outer ring to see how far it is from the center of the BB with various chainlines (47.5, 48, 50, 51, and 51.5mm, etc...) to the chainstay and then leaving enough clearance for any possible chain stuck issues.

    My garage is averaging about 12 degrees at the moment, so my fingers are not up to do all of the measuring until warmer weather hits, but maybe somebody could lay out a chart to see what a single, double and triple crankset measurements at various chainlines would require for clearance.

    BB

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    I have the same exact problem as the OP. Mine is a Medium Jet, 42/28 and 11-36. The chain stuck/suck occurs only on the 28 ring. Bike is pretty new; the chain is almost always kept meticulously clean. These pictures were taken right after the problem occurred. I have about 7 rides on this bike since Christmas, and this problem has occurred twice. I placed a fat zip tie with the lock facing down as close to the weld as possible. I bounced the rear wheel and can see the chain slapping the ziptie. Ordered a smaller set of chain rings. May move/remove/add spacers on the BB. The experts always say to try one thing at a time, and not combine several adjustments at once. I think the ziptie will work but it doesn't look correct. I had a similar chainsuck occur on a Kona Unit set up as a 1 x 9: 32 - 11/34. The chainstay to yoke weld on the Kona has a smoother sweep, and thus the suck is never stuck.
    Attached Thumbnails Attached Thumbnails Et tu, JET 9?  Crankset clearance issues....-p1010213.jpg  

    Et tu, JET 9?  Crankset clearance issues....-p1010214.jpg  

    Last edited by whizbyu; 01-30-2011 at 08:54 PM.

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    Quote Originally Posted by whizbyu
    I have the same exact problem as the OP. Mine is a Medium Jet, 42/28 and 11-36. The chain stuck/suck occurs only on the 28 ring. Bike is pretty new; the chain is almost always kept meticulously clean. T
    Quote Originally Posted by Niner Bikes
    We haven't heard of any issues out there on the trail, and there are a lot of people running XX 2x10 (I've run it myself on the frame with no issues at all, in both the 42/28 and the 39/26).T
    Now Im confused...I thought the big ring has been the issue.

    So while we are on the subject... how about posting your trouble free Jet 9 crank suggestions??
    .. If I see this bike on display with those GT bars, I am bringing my hacksaw!!

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    Quote Originally Posted by Om Flyer
    Now Im confused...I thought the big ring has been the issue.

    So while we are on the subject... how about posting your trouble free Jet 9 crank suggestions??
    I think it may have been that he was in the small ring at the time & the chain got caught up with the big ring & got the chain suck.

    On my Jet 9 I running a tripple ring Rotor crank setup & only using the inner 2 rings,That is 30 tooth granny ring ( with heaps of room ) & 39 tooth in what would be the middle ring spot on the crank & that is were the clearance is getting tighter,but have never had chain suck with this setup.
    The 39 tooth ring on my Jet9 sits 49.5 mm from the centre of the frame to the center of the chain ring.

    My wife Jet9 has 26/39 Sram X9 cranks & they work fine,52 mm from the centre of the frame to the center of the 39 chain ring.
    Last edited by muzzanic; 01-27-2011 at 09:34 PM.
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    Quote Originally Posted by muzzanic
    I think it may have been that he was in the small ring at the time & the chain got caught up with the big ring & got the chain suck.
    Correct. That's the issue when you get over a 40T. Chain on one of the inner rings bouncing up while suspension is active and getting stuck between big ring and chainstay as pictured above. If the chain is already on the big ring - it's not going to bounce up and get stuck.

    BB

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    I wonder if the SRAM derailleur is too soft.
    With the bike on the workstand, when shifting from 42 to 28 the chain almost acts like a trampoline, effectively slapping the bottom surface of the chainstay. It does not matter what cog in the cassette I am in but it does tend to slap more when I'm in a smaller cog.
    With the bike off the stand and the chain on the 28 chainring, if I bounce the rear of the bike, the chain slaps the chainstay pretty consistently. I suppose that when riding on the trail and factoring in forward motion, rear suspension bob, chain tension and chainslap, it is easy to see how the chain gets sucked in and ultimately stuck.
    I put 2 large zipties on the weld, and have been riding it hard consistently using the 28 chainring all weekend. No chainsuck. BUT, the zipties do not look correct. If I didn't have to look at it it wouldn't matter. But knowing that it's there, well, that's a different story. I'd have to have my shrink interpet all that for you.
    So Bruce, what was your ultimate solution that worked? Did you go with the 39/26? What about the spacers?

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    I have a new 2010 Jet 9 with XO 2x10 26/39 and this just happened to me today. I was shifting under load from the big ring to small ring when it happened. I had to back pedal to get it unstuck. I've got a nice chewed up chainstay on a bike with four rides on it. Other than this issue, I like it. I'll have to be a little more careful with how I shift I guess.

    edit: I typed my chainring size in wrong. It is 26/39 and not 29/36. This is still the size that Niner says is compatible with the Jet.
    Last edited by brewer90; 01-31-2011 at 10:12 AM.

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    No doubt it is a great riding bike. I suppose the chainsuck issue occurs even with the smaller recommended gearing, but with better clearance, it's just a suck and not a stuck chain. Which brings forth an even stronger argument for the derailleur spring, assuming you're running SRAM. I think that with repeated episodes of chainsuck the chainstay will develop a deep gouge. That's a hell of a problem given the price we paid for this bike.

    Are you now going to go with the ziptie solution? An outfit that manufactures anti chain suck devices out of Idaho might be the ticket. Tomac had some joint venture project with them but they don't have one designed specifically for the Jet 9...

  46. #46
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    Quote Originally Posted by whizbyu
    No chainsuck. BUT, the zipties do not look correct. If I didn't have to look at it it wouldn't matter. But knowing that it's there, well, that's a different story. I'd have to have my shrink interpet all that for you.
    So Bruce, what was your ultimate solution that worked? Did you go with the 39/26? What about the spacers?
    No I didn't switch rings. 27/40T Rotor Q Rings remain on my race sled.

    I've kept the zip ties on and moved from my 110mm Taperlock Ti Race Face bottom bracket to a Shimano bottom bracket with 122mm spindle. White Industries Ti replacement will be used this season so I can drop the boat anchor Shimano BB.

    I wouldn't worry about the zip ties on there. Heck, if they prevent that chainstuck from occurring - they are well worth it and they weigh next to nothing. I've got 5 or 6 on mine doing battle with the chain. Zero chain stuck issues since installing them and getting a wider BB spindle.

    BB

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    Quote Originally Posted by brewer90
    I have a new 2010 Jet 9 with XO 2x10 29/36 and this just happened to me today. I was shifting under load from the big ring to small ring when it happened. I had to back pedal to get it unstuck. I've got a nice chewed up chainstay on a bike with four rides on it. Other than this issue, I like it. I'll have to be a little more careful with how I shift I guess.

    DAM!! And that is with the recommended largest chainring size for a 2 x drivetrain.

    Houston, we have a problem...


    Get out the zip ties and follow the pictures above to try and keep it at bay.

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    Bruce, u just saved me a trip to my shrink!

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    No doubt we have a problem. I shifted from the middle (32T) to the 22T granny yesterday and had the same thing occur. So it was in the granny gear when it occurred. I was able to back pedal and it dropped right out. You can feel/hear it when it happens. I have two spacers on the right side between the frame and the external Chris King BB and I am using XTR M970 cranks with a 44T large ring.
    Regarding the zip ties.......do you remove the crank and then install them? I had put one on which did not survive the chain suck/almost stuck episode. FWIW, my drivetrain is practically new and the conditions were tough (muddy and wet) yesterday. Niner suggested I clean my chain really good and use Demonde Tech chain lube. I have done that now as of yesterday after the ride so we will see how that works. I do believe it is a chain suck issue at this point. It only happens occassionally and seems to always be during a shift under load. Whatever the case, it should not be getting stuck when it does it!

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    Quote Originally Posted by Niner Bikes
    If your cranks/BB are set up properly the big ring should be out side of the chainstay/yoke. If you are having contact issues between the big ring and the chainstay yoke you are most likely not running the chainrings at the correct chainline position. Double check the installation of the crankset to make sure you have the proper spacers installed on the BB.

    Niner
    I have this same issue and have two spacers on the drive side as recommended from Niner with a Chris King BB and a Shimano XTR 970 crankset. Should I put an extra spacer (to make three) on the drive side? Suggestions please. I guess I will try the zip ties for now.

  51. #51
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    OK so you clean your chain until you can floss with it. Put Demon's Oil, sign up for a 6 hour race. How many times are you going to suck it? Imagine what the competitors will say about you AND your bike.
    www.acecosportgroup.com
    I placed two big zip ties without having to remove anything. They have survived an entire weekend of riding in the small ring.

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    "OK so you clean your chain until you can floss with it. Put Demon's Oil, sign up for a 6 hour race. How many times are you going to suck it? Imagine what the competitors will say about you AND your bike."
    What is your point??????

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    Epi,
    A lot gets lost in the translation/internet. Last post was not directed at you. At this point it is about the consumers and the manufacturer.
    Look at the thread. It's all about the set up. If it is not about the set up, it's about the oil. It's about the chainring. It's about your chainline. Get a 39 and it will work. Well, it did not prevent it, did it? OK lets go back to your chainline and oil.
    The reference to signing up in a competition and what people think about you and your bike has to do with much lesser bikes finishing the race without chainsuck issues, not about your abilities.
    I'm convinced that two factors play a role here: The shape of the weld, and arguably the tension on the chain. I say let's wait on a chainsuck protection device from the folks at Idaho. For now, it's zipties. Getting off my soapbox now.
    Last edited by whizbyu; 01-30-2011 at 08:58 PM. Reason: spelling

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    Whizbyu, gotcha. Yeah unfortunately something is wrong with the "New" Jet 9 . The zip ties actually work but it is ashame we have to do something like this. Now when it sucks at least you can feel it and back off once the chain hits the zip tie BEFORE it sucks up past the chainstay. If the chain stay did not have the sharp edge like bend in it it would probably help. It is ashame that Niner does not acknowledge something is wrong and come up with a suggested improvement/fix versus saying it is worn rings/chain, etc.

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    I'm "prairie dogging" here since I said I got off the soapbox. But I have high hopes that K-Edge might have something available for us in the near future. I had actually thought about putting nail polish on the underside of the fat head of the zipties to see if the chain was hitting it enough to "chip off" the polish (give me some respite that we've found a solution) but I thought I better just take my medications and sit in the corner.
    I'm going back in the hole and keep quiet until I get this resolved. Or not.

  56. #56
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    Quote Originally Posted by whizbyu
    I'm "prairie dogging" here since I said I got off the soapbox. But I have high hopes that K-Edge might have something available for us in the near future. I had actually thought about putting nail polish on the underside of the fat head of the zipties to see if the chain was hitting it enough to "chip off" the polish (give me some respite that we've found a solution) but I thought I better just take my medications and sit in the corner.
    I'm going back in the hole and keep quiet until I get this resolved. Or not.
    Nail polish? Nah. Try it with Wite-Out for a more black and white answer.

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    I guess I'll give the zip ties a try. It seems a bit ridiculous that Niner didn't get this problem solved especially after having it on the RIP. I can understand their argument of not being able to design for every combination of driveline out there but when what they recommend doesn't even work then it is an issue.

  58. #58
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    Hello Everyone,

    I want to let you know that we understand your concerns regarding potential issues on the Jet 9 and that we do check into MTBR threads such as these when we have time.

    Chain suck is a very complicated issue that is difficult, at best, to discuss in threads such as this. MANY factors contribute to it, such as drivetrain cleanliness/lubrication, wear, derailleur spring tension, gear choice when shifting, shifting habits (shifting under load), chain length, and yes, frame clearance from the cranks. While the chain stay yoke clearance from the chain rings obviously plays a part in this chain suck issue, it's not the only thing going on. The Jet 9, and even the new RIP 9, have much improved clearance in this critical area than the RIP 9 frames that were originally having chain suck issues and we continue to combat this as best we can. On a 29" wheel, especially a full suspension 29er with short wheelbase, this is a tight area. Narrow it up too much and chain suck would be eliminated, but so would any amount of decent tire clearance. Obviously, we made improvements on this based on our feedback from the RIP 9.

    Whizbyu's issue is due to a combination of factors:

    - He is running the 42/28 chain rings on his bike. We recommend only using the 39/26, because they provide more clearance.

    - Another factor in this particular case was mud/clay/sand build up (discussed in a phone call), on a brand new, not-been-tested set up. Anytime you ride a bike in harsh conditions you can expect to see drivetrain issues increase, and on a new set up where adjustments might not yet be perfect, this is even more likely. Proper set up will make your bike better in these scenarios and we aim to have bikes that work well across a wide range of possible challenges when adjusted correctly.

    - Next, with all the new drivetrain systems, tolerances and clearances are much tighter than they used to be and require more attention to be in perfect running order.

    I have been working directly with Whizbyu and his dealer to get his bike dialed in so that there are no issues with it. In the same way, I am more than happy to speak with any of you that need similar help. The fastest way to get this help is to call me (1877NINERXC). We are a small company, and I only have so much time that I can spend on the forums each week, but I answer all calls as quickly as possible.

    In an ideal world, the forums would act as a tech library, but there are a few factors that prevent this:

    - components are changing rapidly, and there are a lot of wrong and right combos out there. Calling us directly allows us to address your specific problems quickly, using our all-day, every-day experience with Niner products to make your build as fun and fast as possible.

    - the internet does a poor job of filtering "facts" from facts. A lot of problems are really misunderstandings or simple issues that can easily be fixed, but are lost in the interweb jumble. We have found that being very accessible is a much better way to get your bikes running smoothly. It is our hope that in a world of phone trees and automated help centers, that Niner riders will appreciate prompt, live-person, rider service.

    - Our dealers are also great resources for information. These guys set up lots of bikes and are likely to have encountered any problem you might have.


    Eric
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    1-877-NINERXC
    .........

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    I have relatively new drivetrains on my RIP and JET and am pretty sure that I have had chain suck/stuck on each of them in fairly good riding conditions. I run the exact same setup on both, 970 cranks (22/32/44), XT cassette (11-32), Chris King BB, and a KMC chain. Chain clean and lubed with good lube. The bikes are setup properly with the correct spacers and the chain length is setup by wrapping around the big ring in front and back and adding two links. I think each time my chain suck/stuck problem occured I was shifting from the 32 to 22. So if chain suck/stuck occurs with a "standard" properly setup, setup then what are we to do? Install the zip ties and shift carefully and cross our fingers everytime and just be ready for to possibly occur? I have never experienced this issue with any other bikes after riding/racing for well over ten years. I love both bikes other than this slight annoyance.

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    Epiphreddy,

    Often when shifting into the granny gear on the crankset is when you are in the middle of a climb and more pressure on the system is involved. There are a few things going on here. Shifts in the front are a lot harder for a derailleur to manage because the difference in teeth is much greater than in the rear. There is a much higher chance that something will jam because there is more time that the chain is between chain rings. With a full suspension bike it compounds the issue because the angle that the chain is leaving the chain rings is changing constantly due to the suspension cycling. It is always recommended to shift the front derailleur before you get to the climb then use the rear derailleur to dial in your gear selection.

    If you have any further questions feel free to call me.
    Eric
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    Thanks Eric. That makes sense and I can honestly say that I think it has occured while under somewhat of a load. What about the B screw on the rear derailleur? Should it be turned "in" a significant amount to draw the derailleur back to tension the chain?

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    1) Changed out the 42/28 for a 39/26
    2) Removed all the zipties

    Rode the hell out of it this past weekend: berms, roots, rocks. NO CHAINSUCK. NO CHAINSTUCK.

    Thank you!

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    This thread has been a good source of info for me.
    Saved me a lot of trouble. Ended up salvaging my old triple XT & installed a 28/40 combo on it. 8 rides, no issue. Thanks all for your sharing & positive feedback and discussions.

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    Quote Originally Posted by rizal
    This thread has been a good source of info for me.
    Saved me a lot of trouble. Ended up salvaging my old triple XT & installed a 28/40 combo on it. 8 rides, no issue. Thanks all for your sharing & positive feedback and discussions.
    Glad the thread is serving as a good source of info.

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    So what suggestions are there for those of us using an XTR 970 crankset? Does Blackspire or anyone else make a 39 large ring for the 970? What is the size threshold of the large ring where this becomes a problem? I rode last weekend in the mud and if it weren't for the zip ties I would have had chain stuck on several occasions.

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    going from 3x9 to 2x9 shifting question

    Hi - It's a little off topic: I currently have a standard 3x9 XT crank and I'm considering removing the large chainring, putting in spacers and using the extant XT FD. My question is this - since I don't have to move up to the big chainring, can I lower my FD to the point where it's 2mm above the middle ring (as I would do with the large chainring). Assuming I don't change my chainline by adding or removing BB spacers, will this improve my shifting or am I better off leaving shifting as is? Thanks.

    Chris
    2010 Jet9

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    Quote Originally Posted by cjcrawford
    Hi - It's a little off topic: I currently have a standard 3x9 XT crank and I'm considering removing the large chainring, putting in spacers and using the extant XT FD. My question is this - since I don't have to move up to the big chainring, can I lower my FD to the point where it's 2mm above the middle ring (as I would do with the large chainring). Assuming I don't change my chainline by adding or removing BB spacers, will this improve my shifting or am I better off leaving shifting as is? Thanks.

    Chris
    2010 Jet9
    Hi you could lower it a bit but you would need to let the air out of the shock so the suspension was at its max travel & make sure that the bottom of the derailier has plenty of clearance with the rear triangle.

    Note the proper 2x10 front derailiers are shorter
    I have a 6 Berth Motorhome that I rent out . It is based in Tauranga, New Zealand

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    Hi all,
    A little more info on the mod I did to the XT cranks. Not sure of the model, its the first out board BB from Shimano.
    Using Blackspire 28t on the inner most ring (BCD 68?) and 40t on the 104 BCD.
    No bash ring was installed, so shorter crank bolts were used. Liking the raw look of this setup, plus easier for cleaning too :-)
    The SLX FD was lowered to accommodate the mod.
    Hopes this will help as much as the thread has helped me.

    p.s in the office now, replying on my phone. will post pics when I can. Cheers!

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    To be exact, installation done by my trusted bike mech. Not me...

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    To avoid this issue for those of us running a triple, should we ditch the 40/42 and run a 38 big ring?????

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    Quote Originally Posted by epiphreddy
    To avoid this issue for those of us running a triple, should we ditch the 40/42 and run a 38 big ring?????
    I thought the zip ties were working for you?

    Russ Anderson's 30/40T middle and large ring combination took care of all woes on my triple for the RIP. I wouldn't hesitate to go that route on my JET if I was running a triple.

    Russ is fairly aware of the situation on the RIP and JET and pretty much can build what you need to ease your woes. Anybody wanting to know what led to his development of his new middle and outer rings should read the RIP 9 clearance issues thread. It is also filled with oodles of pictures of 42T and 44T rings and all the clearance issues, millimeter measurements and thought process. Many just gave up on a triple, dropped the outer ring and threw a bash ring on the crank. I wanted to stick with the triple to cover all my riding needs on the RIP and went for Bruzed's (Russ Anderson) rings.

    Here's the thread. Very similar to the JET and the sole reason I started this thread when I did last July. Some are not having problems with a 42T on a triple due to having the correct amount of spacing between ring and chainstay/yoke area to prevent the stuck issues.

    BB

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    The zip ties help but they seem to only be a temporary fix until the chain hits them hard enough to move them a bit. I think I will remove the crank completely and re-do them. I don't seem to have this problem on my Rip or at least not as bad. The Rip's crank/chainrings are newer ( XTR's also). I just bought a new XTR M970 crank for the Jet and was thinking I might sell the large ring (44T) and get a 38T Blackspire that would be much more useable anyways.
    I have an older XTR crank (on the Jet currently) that I think I am going to try a 2 x 9 on for racing. I was going to go with a 24t Blackspire SuperPro M970X granny and a 36T SuperPro Middle. Anyone tried this combo or anything similar? There do not seem to be too many options for the XTR cranks and I need to come up with something to avoid this issue hopefully all together.

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    Quote Originally Posted by epiphreddy
    The zip ties help but they seem to only be a temporary fix until the chain hits them hard enough to move them a bit. I think I will remove the crank completely and re-do them. I don't seem to have this problem on my Rip or at least not as bad. The Rip's crank/chainrings are newer ( XTR's also). I just bought a new XTR M970 crank for the Jet and was thinking I might sell the large ring (44T) and get a 38T Blackspire that would be much more useable anyways.
    I have an older XTR crank (on the Jet currently) that I think I am going to try a 2 x 9 on for racing. I was going to go with a 24t Blackspire SuperPro M970X granny and a 36T SuperPro Middle. Anyone tried this combo or anything similar? There do not seem to be too many options for the XTR cranks and I need to come up with something to avoid this issue hopefully all together.
    I'm currently running a 36/22 middleburn rings on a Truvativ Firex GPX crank. Its cut down the chainstuck issues I was having big time. Still running with the zip ties since dropping to granny ring can sometimes cause chainstuck if I shift to late (Only happen once in the past 150km). Otherwise its been fine.

    Just wish someone would bring out (or I could find) a double crank which has a 24T inner.

  75. #75
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    I am about to get on the phone to order a 24 and 36 right now. I am going to go with an XTR 970 crank and 24/36 Blackspire rings. Emailed Blackspire and Aaron was very helpful. For the XTR crank you HAVE to use the 970X chainring for the granny (64mm) and the SuperPro's will work for the Middle and Big Ring. Of course there was only one place I could find that had the 970X - Bike.com and their SuperPro rings are $20 more than Price Points. Hopefully they will pricematch. Bike.com currently has free shipping for orders over $69.
    You should be able to use the SuperPro ring with your Truvativ cranks also so you could use a 24T afterall. Cheapest place to find is Price Point.
    http://www.pricepoint.com/detail/200...-Chainring.htm

  76. #76
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    2 Niner bikes

    I've had 8 mountain bikes in 3 years. I love my Niner RIP and Niner Jet over everything else, even though the others never had chain suck of any type. My RIP chain suck happened 2-3 times per ride. It was really bad. Took forever to get the chain out. The Jet doesn't happen so often, but when it does I can usually sit back on my rear seat and back pedal to get it out. It does wear on the frame. I have a pristine frame, but a chewed up chain stay. My RIP looks like someone used a zip saw on the chain stay. I've monkeyed with my Niners for 2 years to get something that works and I've settled on a 2x9 setup. If I wanted a 3x9 I'd have to sell my Niners, there's just no way it would work I don't care what the specs say on their website. But Niner rules. I climb stuff easily that my previous 4k bikes couldn't manage at all. If I had one bike, it would be the RIP and a new rear triangle every 2 years. These pictures are of my 3 month old Jet. My RIP was just awful until the rear triangle cracked and I got a factory new triangle. There was nearly 1/4" of metal gouged from all the chain suck. The crack was on the opposite side though. I think I got one of the early RIPs before they tweaked the triangle. One last comment. The white Jet below, I keep the chain stay wrapped with kevlar liner and zip ties. But, the chain would wear through before I finished a ride.
    Attached Thumbnails Attached Thumbnails Et tu, JET 9?  Crankset clearance issues....-niner1.jpg  

    Et tu, JET 9?  Crankset clearance issues....-niner2.jpg  

    Et tu, JET 9?  Crankset clearance issues....-niner3.jpg  

    Last edited by andyaustin; 07-10-2011 at 11:09 PM. Reason: added clarification to pictures

  77. #77
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    2 x 9 solves all of the chainstuck issues, at least for me. A 24/36 with a 11/34 cassette works great.

  78. #78
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    Quote Originally Posted by epiphreddy View Post
    2 x 9 solves all of the chainstuck issues, at least for me. A 24/36 with a 11/34 cassette works great.
    Luckily, Rotor came out with their Q rings in 25/38 this year with all the clearance issues on "modern" bikes and the trend/movement/philosophy what have you have 2 x __ drivetrains.

    My 27/40 rings were getting worn, so I just installed the 25/38 Q rings and the clearance improvement is pretty impressive compared to the 27/40.

    <a href="http://www.flickr.com/photos/7166535@N05/6886941392/" title="Clearance with 25/38 Rotor Q's by BBcamerata, on Flickr"><img src="http://farm8.staticflickr.com/7097/6886941392_21e02ecace.jpg" width="487" height="500" alt="Clearance with 25/38 Rotor Q's"></a>

    Clearance was so good in fact, I went back to the 110mm spindle RaceFace Taperlock Ti BB to shave 11mm off my Q factor and allow nice cross chaining to utilize every gear with both rings up front. I really tried to recreate the dreaded "chainstuck", but cannot do it - at least on pavement, gravel and hill climbs. Singletrack XC race tomorrow, so we'll see how the JET does with the smaller rings and clearance. I was very meticulous installing the new chain to get the right length and go as short as I possibly could and still allow enough chain growth for the suspension.

    <a href="http://www.flickr.com/photos/7166535@N05/6886941130/" title="JET ready to RACE for 2012 by BBcamerata, on Flickr"><img src="http://farm8.staticflickr.com/7046/6886941130_2737e93b5b.jpg" width="500" height="282" alt="JET ready to RACE for 2012"></a>

    Fingers crossed that Rotor's new 25/38 rings will function as well as some other brands have been on JET 9's. I did notice on a training ride, I can now spin out - so I miss having a 40T or 42T for those muscle sprints to the line, or flying down hills to get as much momentum as possible for the next climb.

    BB

  79. #79
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    I've had some serious chain suck issues with my 2011 Jet 9 setup and wanted to share my saga.

    Problematic Setup:
    2011 Jet 9 Medium
    Shimano XT Cranks (9 speed triple converted to 10 speed double)
    Blackspire 26t and 38t chainrings
    Shimano XT double front dérailleur
    Shimano XT 10 speed chain (chain was one link too short (IMO) but shifted fine in my bike stand)
    Shimano XT 10 speed cassette and rear derailleur

    Situation: Chainsuck shifting from the big chainring to the small. It occurred in every condition: wet, dry, dirty chain, and clean chain.

    Fix 1:
    I read this thread
    Then determined that the zip ties were the easiest fix and I installed them.
    Switched from a wet lube to a dry one.
    Crossed my fingers and went for a ride. Unfortunately the zip ties didn't work at all. In addition to the chain suck, 2 of the 4 zip ties got ripped/chainsawed off my bike.

    The fact that the zip ties got ripped of led me to believe they were trying to work but my problem was too severe to be handled by little plastic strips.

    Fix 2:
    I read this thread again.
    Looked at my bike and determined the gap between my 38t chain ring (installed on the middle chain ring position) had enough clearance between it and the yoke.
    Reinstalled the zip ties
    Bought a new chain because I thought that maybe the chain was too tight.
    Vowed to change my shifting style.
    Fixed the zip ties and cleaned the drive train again.
    Sadly, these fixes didn't solve the problem either.

    As a side note, the KMC X10SL chain that replaced the Shimano XT chain shifts across the cassette SOOOOO much better.

    Fix 3:
    I read this thread again.
    This time I decided to make a major change and added a 1mm bottom bracket spacer to the drive side. What else was there to do? Buy a new crank? Go back to 1x10? No thanks.
    Readjusted my front derailleur to compensate for the changes.
    Cleaned everything (I switched back to the wet lube b/c the dry stuff made too much noise)
    And went for a ride.........And it worked!!!! No chain suck.

    For the past month I've been chainsuck free. It's a wonderful feeling when your bike works correctly.

    Thanks BB for posting this thread. Reading other people's experiences helped me solve this problem "on my own". Keep up the good work.

  80. #80
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    Quote Originally Posted by ppfeifer View Post
    I've had some serious chain suck issues with my 2011 Jet 9 setup and wanted to share my saga.

    Fix 3:
    I read this thread again.
    This time I decided to make a major change and added a 1mm bottom bracket spacer to the drive side. What else was there to do? Buy a new crank? Go back to 1x10? No thanks.
    Readjusted my front derailleur to compensate for the changes.
    Cleaned everything (I switched back to the wet lube b/c the dry stuff made too much noise)
    And went for a ride.........And it worked!!!! No chain suck.

    For the past month I've been chainsuck free. It's a wonderful feeling when your bike works correctly.
    on Fix #3 solving your dilemma. Chain "stuck" is not a fun thing to deal with on the big wheel suspension bikes.

    BB

  81. #81
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    Quote Originally Posted by andyaustin View Post
    I've had 8 mountain bikes in 3 years. I love my Niner RIP and Niner Jet over everything else, even though the others never had chain suck of any type. My RIP chain suck happened 2-3 times per ride. It was really bad. Took forever to get the chain out. The Jet doesn't happen so often, but when it does I can usually sit back on my rear seat and back pedal to get it out. It does wear on the frame. I have a pristine frame, but a chewed up chain stay. My RIP looks like someone used a zip saw on the chain stay. I've monkeyed with my Niners for 2 years to get something that works and I've settled on a 2x9 setup. If I wanted a 3x9 I'd have to sell my Niners, there's just no way it would work I don't care what the specs say on their website. But Niner rules. I climb stuff easily that my previous 4k bikes couldn't manage at all. If I had one bike, it would be the RIP and a new rear triangle every 2 years. These pictures are of my 3 month old Jet. My RIP was just awful until the rear triangle cracked and I got a factory new triangle. There was nearly 1/4" of metal gouged from all the chain suck. The crack was on the opposite side though. I think I got one of the early RIPs before they tweaked the triangle. One last comment. The white Jet below, I keep the chain stay wrapped with kevlar liner and zip ties. But, the chain would wear through before I finished a ride.

    How in the world did you get kermit green paint under your white rear triangle? Did you repaint it, or was it that way from the factory, as in you got a replacement rear triangle repainted?

  82. #82
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    I had "chainstuck" for a while on my 2011 Jet. My fix was to swap first to an SLX 9 speed double crankset and most recently to a Stylo 3 x 9 with the GXP BB. I haven't had chainstuck with either, despite the fact that the clearance is the same as with the Race Face crankset and Shimano BB I originally tried to run.

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