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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.

    WideYokeRIP

    YokeIssues

    WideYokeChainStuck

    BB
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  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.

  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.
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  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....
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  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
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  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.
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  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):

    JET's Clearance

    Taperlock BB smaller portion of ring

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

    Taperlock BB larger portion of ring

    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:

    Yoke Damange and Zip Tie Parage

    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.

    40T Clearance on RIP - beautiful clearance

    40T Clearance on RIP - beautiful clearance

    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?

    JET Clearance

    JET Clearance

    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.
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  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
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  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
    The 14 warmest years have all occurred in the 16 years since 1997.

  19. #19
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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  

    .........

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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?
    The 14 warmest years have all occurred in the 16 years since 1997.

  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):

    Shimano 122mm spindle



    BB
    The 14 warmest years have all occurred in the 16 years since 1997.

  22. #22
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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
    The 14 warmest years have all occurred in the 16 years since 1997.

  24. #24
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    The new 10 speed XT cranks are 24/32/42 & will work great to.

  25. #25
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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.

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