please help- what derailleur with Tiagra shifters/8 speed cassette- Mtbr.com
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  1. #1
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    please help- what derailleur with Tiagra shifters/8 speed cassette

    run 1x8 on my commuter (steel hardtail with drop bars)

    came across a steal for some Tiagra shifters

    they won't work with my current extra derailleurs I have laying around (8 speed XT and 8 speed Alivio)

    Shifters will work with Tiagra or 105 rear Der. and either an 8 or 9 speed cassette, correct? I'd like to keep the 8 speed for a bit and potentially upgrade later.

    What other derailleurs will work with the Tiagra shifter/8 speed 11-32 cassette I run now?

    I'm not sure which 9 speed MTB derailleurs are backwardly compatable.

    thanks a lot

    -Drew

  2. #2
    weirdo
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    Any 9 speed Shimano RD should work with 9 speed Tiagra and 9 speed Shimano or Sram casette or 10 with 10, if it`s a current Tiagra. To run an a cassette with a different number of cogs than your indexed shifters are made for, check to see if there`s a shiftmate model for what you want to do. Otherwise, you`ll either have to get different shifters or cassette. I think Sora is still 8 speed, probably have to eBay for a higher level STI in 8 speed.

    EDIT: Yeah, A.S. is right. Whatever derailers you`ve got should be fine as long as it`s rated for the biggest sprocket on your cassette or bigger. I don`t know why I said 9 speed- you just have to match shifter and cassette by number.
    Last edited by rodar y rodar; 06-05-2009 at 03:55 AM.

  3. #3
    Fat-tired Roadie
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    I'm confused...

    Shifters have a certain number of speeds. Tiagra's a 9-speed group, unless you got older ones.

    Cassettes have a certain number of speeds.

    Did you try the derailleurs you have? Either of them should work. If I were you, I'd just buy a cassette to match my shifter and use one of my existing derailleurs. Shimano doesn't necessarily encourage using 8-speed derailleurs in 9-speed drivetrains, but if there's any difference between an 8-speed and a 9-speed derailleur from the same group in close years, it's in the width of the cage and the jockey wheel. In practice, it shouldn't be a problem. Cassettes are cheap and if you're going to need some kind of adapter to keep your old one, you're committed to spending money either way.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  4. #4
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    well, I don't even have the shifters yet...

    guess I will upgrade the cassette on my XC bike and just throw the sram 970 off of that on the commuter-

    that "should" work with one of my existing derailleurs (XT probably will be what I use) so long as I have the 9 speed shifters?



    the other thing I was suggestion wouldn't have worked eh? Those derailleurs would work if you had 8 speed shifters though and 8 speed cassette. right?

  5. #5
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    Derailleurs don't know how many speeds you're running. They're just sensitive to cable tension. Shimano's derailleurs have had the same actuation ratio for a pretty long time, so any Shimano derailleur for an indexed shifting system should work with any Shimano shifter. They'll also work with friction shifters and the SRAM Attack group. The only exception is older Dura-Ace derailleurs - they had a different actuation ratio.

    If you haven't already found Sheldon Brown's web site, go check it out. He's got tons of information about the mechanical aspects of bicycles, at least through 9-speed systems. He died recently (RIP, Sheldon) and nobody seems to be writing new articles, but it's a great resource for anything but a new racing bike. The Park Tool web site has some information as well, but I don't like it as much.

    Bear in mind that road derailleurs are typically designed for a 27-tooth or smaller big cog. I'm not sure if it's a problem in practice, but they may not move away from the cassette enough as you shift into easier gears. I'd try using the XT derailleur first, and consider an inexpensive short cage MTB derailleur if you want to put the XT on a nice bike later.

    What kind of wheels are you putting on that bike? Have you been able to ride it at all yet? I had some thoughts about building a drop bar road bike on a hardtail frame a while ago - it seems like it should have pretty insane power transfer and great stability in city streets. Might need a really short stem, though...
    Last edited by AndrwSwitch; 06-05-2009 at 10:58 AM.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  6. #6
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    yes- it has almost 700 miles on it since I converted to drop bars in early april. mostly dirt roads and commuting. wheelset is period (bike is 96 marin pine mountain) xt hubs with mavic wheels. run tom slick 26x1.4s. until now have been rocking alivio rear derailleur and mtb shifter just ghetto rigged. I used short reach, narrow womens drop bars and purchased a new stem. I currently have a nicely built mamasita and an 03 s-works road bike and still grab this off the wall for mixed gravel/pavement riding. I even raced 105 miles of gravel a few weeks back and did well. thinking the shifters will be huge upgrade.

  7. #7
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    For indexed shifting, just match the number of speeds on the shifter to the cassette and any rear derailleur you want. On my Pugsley I'm running a 7spd cassette to 9spd rings on the crankset with brand new XT front and rear derailleurs and vintage Deore 7spd thumb shifters. Works flawlessly. Just keep your Shimano with Shimano and your SRAM with SRAM. SRAM and Shimano cassettes are interchangeable.

  8. #8
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    well, I will give it a go tomorrow with the XT derailleur.


    my Mamasita has x9 rear derailleur and the 970 cassette on it currently- it doesn't make sense to upgrade past the 980 right?

  9. #9
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    Do you like a 32t or 34t big cog? I wouldn't upgrade past the 970 if I only used a 32t...
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  10. #10
    weirdo
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    Quote Originally Posted by 2silent
    yes- it has almost 700 miles on it since I converted to drop bars in early april. mostly dirt roads and commuting. wheelset is period (bike is 96 marin pine mountain) xt hubs with mavic wheels. run tom slick 26x1.4s. until now have been rocking alivio rear derailleur and mtb shifter just ghetto rigged. I used short reach, narrow womens drop bars and purchased a new stem. I currently have a nicely built mamasita and an 03 s-works road bike and still grab this off the wall for mixed gravel/pavement riding. I even raced 105 miles of gravel a few weeks back and did well. thinking the shifters will be huge upgrade.
    Sounds nice- I wouldn`t mind seeing some pics when you get it figured out. My touring bike is a similar critter, mid 90s rigid Schwinn mtb with short reach drops and either 1.25 or 1.75 tires, depending. I used 8 speed bar end shifters, they were less than $60 brand new and can be found for peanuts on eBay every day. I`ve seen other mtbs that people managed to clamp down tube shifters on and that seems to work out well too, but it`s tough to find clamp on shifters for OS tubing. I think for the two that I saw the guys had to file and stretch the clamp bands a good bit.

  11. #11
    weirdo
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    Photo Op

    Sorry- can`t resist the chance to post a pic on my newest!
    Attached Images Attached Images

  12. #12
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    1x9 29er means I like the 34

  13. #13
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    Huh... How big's your chainring?

    Anyway, according to SRAM, you knock off 100g on an 11-34 going from a 950 to a 970. A few more going to a 990, but not much. On an 11-32, the differences between a 950, 970 and 990 are pretty small, imho. If the shifting gets better, great, but it looks like a weight difference and not a performance difference to me. I can't be bothered to price check, but a 100g savings seems like it would be worth a little extra. Less than that is weight weenie territory.

    My road bikes bottom out around a 3:2 ratio - 30 or 32 to 26. That's plenty low for road riding on skinny tires but I wish I had some lower gears available on my cross bike. Maybe a 30t cog or even a 32. Are you going to be on pavement only with this bike, or does it go off-road from time to time?
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  14. #14
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    this bike (marin) is 44 tooth up front and currently 11-32 (8 speed) rear- it is used primarily for gravel road riding and commuting.


    since I needed a new cassette though (I don't have an extra 9 speed laying around) I figured I would upgrade the cassette on my Mamasita- that bike is 32 tooth up front with 11-34 970 cassette. I probably don't need the 34- but it sure is nice to have that relatively easy ratio for long climbs or when riding slow with friends.

    I will try to get some pictures of the Marin-- I did post some a long while back when I first converted it to drop bars.

    I will probably just buy a 990 if I can figure out where to get it cheapest

    I will also need another chain-

  15. #15
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    is up and running with the Tiagra up front, XT derailleur and 11-27 Ultegra 9-speed cassette. Shifts smooth and quiet. will go for a couple hr ride here in the fog soon.

    really shouldn't be running the ultegra cassette- stole it off the road bike to see how this would work. Have 11-23 dura ace on the road bike for now- honestly both bikes are geared too hard as they are.

  16. #16
    weirdo
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    Great! How`s your fit? No problems getting the bars in a comfy position?

  17. #17
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    fit is just fine- I'm a young, flexible guy too though (and I've spent like a thousand hrs on bikes this year). It is definitely within the realm of being close to a proper fit too.

    The biggest issue I have with the bike is the bottom bracket height- I'd prefer being closer to the ground. I think that would slightly improve handling and keep me out of the wind plus it would look more proper.

  18. #18
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    Quote Originally Posted by 2silent
    The biggest issue I have with the bike is the bottom bracket height- I'd prefer being closer to the ground. I think that would slightly improve handling and keep me out of the wind plus it would look more proper.
    What kind of fork do you have? I had a bike with a sluggish handling feel and went to a shorter fork, and it improved that a lot.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  19. #19
    jrm
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    anything..really

    using a 11-32 cassette you might try a mid-long cage MTB RD.

  20. #20
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    I have suspension corrected tange fork- it isn't the problem with the handling. I'm just being picky (plus my other road ride is an s-works)

    I rode 80 miles of gravel/pavement in the rain today starting in Rochester and finishing in Red Wing. things worked well.

    Here are a couple quick pictures of the bike (cell phone pics- as my slr was stolen)-




  21. #21
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    That looks pretty badass. Sort of a post-apocalyptic monstercross racemuter. I hate you.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  22. #22
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    thanks man- it really does work well too.

    here is my next question-

    have this on my commuter '96 Marin Pine Mountain that I've converted to 1x9 and fully rigid etc. etc. with drop bars.



    I'm currently running the stock 44 tooth big ring and have some problems with losing the chain at times. I would also like to run a 40-42 tooth ideally as that would still provide me with plenty of top end (26" wheels and 11-27 ultegra cassette).



    should I purchase a new big ring? who makes one that fits in that range? or should I just wait and purchase a whole new crank and bottom bracket etc. etc. soon? I've owned the bike since new and it is totally stock and never opened up down there. I have already put 700 miles on it this year.



    if you recommend that I update crank/bottom bracket (or even if you don't) can you please give a brief synopsis of what i'm looking for so far as finding something that will work with it? My mechanic skills are improving etc., but I'm a bit lost when it comes to the different bottom bracket and crank options.



    thanks



    -Drew

  23. #23
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    Quote Originally Posted by 2silent
    I'm currently running the stock 44 tooth big ring and have some problems with losing the chain at times. I would also like to run a 40-42 tooth ideally as that would still provide me with plenty of top end (26" wheels and 11-27 ultegra cassette).



    should I purchase a new big ring? who makes one that fits in that range? or should I just wait and purchase a whole new crank and bottom bracket etc. etc. soon? I've owned the bike since new and it is totally stock and never opened up down there. I have already put 700 miles on it this year.



    if you recommend that I update crank/bottom bracket (or even if you don't) can you please give a brief synopsis of what i'm looking for so far as finding something that will work with it? My mechanic skills are improving etc., but I'm a bit lost when it comes to the different bottom bracket and crank options.
    You're having problems with dropping the chain for two reasons. One is that the chainrings in a modern multi-speed drivetrain are designed to shift well, so the teeth are lower and sometimes a few of them even have chunks cut out of them to facilitate the chain coming off. The front derailleur does a pretty good job keeping it on most of the time, so on a multi-speed bike, it's not a problem. Throw out the front derailleur and that neat shifting ability isn't so cool anymore. Not having a front derailleur is your other problem.

    The quick and dirty solution is to put your big ring in the middle ring position and a chainguard in your big ring position, then either put another chainguard in the small ring position or put a chainwatcher on your downtube. Depending on the type of crank you have, you may have some trouble finding an appropriate one. You need to know the bolt circle diameter of your crank. 104/64 is pretty common on most Shimano cranks and the de facto standard lately for non-Shimano, but it never hurts to measure. http://www.sheldonbrown.com/gloss_bo-z.html Putting a singlespeed chainring, assuming it's compatible with your chain, on the bike may also solve the problem, but I wouldn't be too confident if you ride it off-road.

    These guys have tons of stuff for converting road cranks for singlespeed applications. They may or may not have appropriate things for the crankset you have.
    http://cyclocrossworld.stores.yahoo.net/chainrings.html I've never dealt with them.

    If you decide to get a new ring, a singlespeed ring for a 3/32" chain should do the trick. There can be compatibility issues with using singlespeed and especially track chainrings in 1x9 setups because the chain for a 9-speed drivetrain is slightly narrower than the one for a 5-speed drivetrain and 1/32" narrower than the one for a track chainring. Whether or not this is a problem in practice varies. But make sure to do your research when you choose one.

    As far as bottom brackets are concerned... That's a pretty huge body of knowledge, much of it trivial. I would expect a bike from the mid-90s to have either a square taper bottom bracket or some kind of ISIS or Octalink thing. Basically, the axle has either a square interface or a splined, funky-shaped thing. You need to match size and type if you're replacing the crankset but not the bottom bracket. Bottom brackets are cheap, though, and wear out - if it's the stock, 15-year-old one, I wouldn't try to match it - just buy a new one to match the crank you want.

    The new, external bearing ones put the bearings outside the bottom bracket shell, as the name implies. They're supposed to be better. I'm not going to weigh in on whether or not this is true. Certainly they've become more common on new bikes and most new cranksets will require one. There are a few different standards, so you may be committed to one company's bottom brackets if you buy their crank - make sure that either you'll be happy with their bottom bracket or you can replace it with a King or Shimano bb if and when it wears out.

    I guess the main point here is that, to me, it makes the most sense to either continue to maintain the current setup, or maybe buy a chainwatcher and the chainring in the size you want and file off the teeth on your old one to use it as a guard, or replace the crankset with one that comes out of the box with the chainring you want, a chainguard, and a bottom bracket, and accept that that's going to be pretty expensive.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  24. #24
    weirdo
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    Lookin groovy! It sounds like you had a nice ride, too- I love gravel roads. I can`t offer anything about throwing your chain since I`ve never had to investigate that problem, but it sounds like the last poster knows what he`s talking about- hopefully some of his suggestions work out for you. What do you have on there for tires?

  25. #25
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    Ritchey Tom Slick 26x1.4- they are great

    the chain thing is currently once about every 100 miles or so- just once in a while I'll be riding along and make a routine shift and it hops right off. I have checked the chainline carefully etc. and it really does seem that just getting an appropriate single speed ring up front should work. I will probably just order one up here soon.

    -Drew

  26. #26
    PCC
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    Quote Originally Posted by AndrwSwitch
    The quick and dirty solution is to put your big ring in the middle ring position and a chainguard in your big ring position, then either put another chainguard in the small ring position or put a chainwatcher on your downtube.
    This is great advice. Your current setup has the large chainring mounted on the outside position and this places a bias on your chainline towards the outside. When riding in the 42/27 or 42/25 combos you are seriously cross-chaining and this could lead to your dropped chain but it absolutely will increase wear on the chain, cogs, and chainrings. By moving the chainring to the middle position you are lining the chainring up with the cassette so that you are reducing the cross-chaining which will help all around. I would go so far as to say that you may not need to do anything more than to move the chainring over and you may not experience a dropped chain again.

    You need to know what the BCD of the chainrings are before buying. I'm pretty sure it's not 104mm. It might be 110mm. There's an easy way to measure this. Follow this link.

  27. #27
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    I agree/understand what you are saying (and I may take it and also run a bashguard), but for whatever reason the chainline is actually quite good using the outside location. I measured both prior to installation and this is right at 50mm of spacing or whatever the LBS guys suggested?

    Strangely enough the chain usually drops when I'm shifting on the harder half of the cassette. also, it always drops to the outside currently.

    who makes the cheapest/simplest bashguard for this application? I may ride the bike over a log or two every once in a while, but it doesn't even need the strength of my straitline guard on the XC bike.

    -Drew

  28. #28
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    Actually, neither of these sounds strange to me.

    Dropping the chain is a problem exacerbated by low chain tension, like if you're in a smaller/harder cog.

    I was a little surprised to read that you had better chainline in your outside ring position than in the middle position, but then it occurred to me that mountain bikes have 135mm rear dropout spacing, so the cassette sits 2.5mm further to the right of center than on a road bike.

    Unfortunately, that second thing is going to make the chainguard solution less simple. If you want to maintain your present chainline, you need the guard to sit to the right of the chainring. My instinct would be that you could do this by using a somewhat longer chainring bolt, and putting a spacer between the outside chainring and the chain guard. But I'd talk to a better mechanic than me about it.

    Before you do that, though, consider removing a link - can you, or will it make your chain too short to use your large/easy cog? Also, consider putting on a singlespeed chainring. If the chain ring you have has lower teeth than the singlespeed ring you want, the higher teeth might be enough to solve the problem, assuming you shortened the chain appropriately when you changed rings.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  29. #29
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    Quote Originally Posted by 2silent
    who makes the cheapest/simplest bashguard for this application? I may ride the bike over a log or two every once in a while, but it doesn't even need the strength of my straitline guard on the XC bike.
    http://www.bbgbashguard.com/Mountainbike.html

    Probably this guy.

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