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  1. #1
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    04 Stumpjumper FSR Expert Disc Chain Drop

    In January I bought a 04 Stumpjumper FSR Expert Disc bike. This was a major improvement over my 10 year old K-mart special. At least I used to think that was an improvement. From day one I have dropped the chain on to my BB. I had my LBS adjust it only to have it drop right after the adjustment. I have had three different shops look at the problem.

    Most of the time it is when I am riding the mountain. After six months of riding the bike and walking on eggshells trying not to hard shift and drop the chain I took it to the pros of CO Sports Garage. They said the drive train is not aligned and sold me an adjustable BB and Truvativ cranks. They adjusted the BB to pull the crank all the way to the frame. Later I took it out on the mountain and the chain dropped yet again.

    I am a runner transitioning to mtn bike racing. I race short track and 15 – 25 mile mountain bike races. If I can eliminate jamming my chain I can move up the ladder a few notches as the time shows only seconds between riders. I am spending about a minute or so un-jamming the chain every race.

    My question is: Is the chain drop a problem with Specialized bikes or with most FSR bikes? I am considering selling my bike for one that will keep the chain on the drive. Is there an aftermarket product I can purchase to keep the chain on the small ring instead of my frame?

    Stanomatic

  2. #2
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    That will happen to every bike, if you don't know how to ride it. Try not to shift while under full pressure.
    Start off slow & taper off from there.

  3. #3
    Maestro
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    1) One thing to check is Chain length. If the chain is too long, it will have very little tension when you are in the granny ring.

    For my 04, I had to remove two links from the chain. I deflated the shock, compressed the suspension. With just the chain, no derailleurs, put it on the large ring on both the crankset and the cassette. With the chain pulled tight, you should have two extra links pointing down.

    I found the chain to between two settings, too many links (3) or too few (1). I chose the too few length and reassembled everything. I then very carefully cycled the rear suspension to check for chain bind. There was still enough travel left in the rear derailleur jockey wheels.

    Doing this helped my Stumpjumper and my NRS.

    2) But, If the chain is in too big a ring in the cassette, shifting into granny will still sometimes through it off. You probabley don't want to here that. I have to remember to make my move to granny when the chain is in the middle of the rear cassette.

    My .02

  4. #4
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    Maestro makes a really good point but I would try to avoid shifting to the granny when you're in smaller sprockets in the back. This will help keep more tension on the chain. Also you might consider switching to a sram drivetrain. The x.0 rear derailleur can be adjusted to maximum spring tension to help with this problem. If you have questions about your chainline, take a look with the rear on the middle cog and the front on the middle ring the chainline should be straight. If it deviates, it's not setup right. The bike was designed to run with a certain width bottom bracket and if it's adjusted up next to the frame I doubt it's aligned right. Also, and I realize this may be obvious, but check your front derailleur. It should move JUST enough to drop it to the granny and no more. If you've got extra space when it drops that may be why it's dropping off. Another thing to think about - if you're not already running a 34t cog in the back, you might consider it. This would give you a lower gearing while still in the middle ring allowing you to ride longer before having to bail out to the small ring.

  5. #5
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    Good Tips

    >> That will happen to every bike, if you don't know how to ride it. Try not to shift while under full pressure.<<

    Yes, after 6 months of every ride dropping the chain I know not to do that. That was my point with phrase “After six months of riding the bike and walking on eggshells trying not to hard shift and drop the chain…” Thank you any way for the tip.

    Maestro and mward – thanks for the tips. I just can’t help to think that with 5 separate mechanics and $$$ upgrades this problem can not be resolved. I am going to take your suggestions to the bike mechanics and discuss. I do follow what you are saying mechanically but I have paid good money for their labor that I would like them to follow through with their guarantee of work.

    Mward - >> If you have questions about your chainline, take a look with the rear on the middle cog and the front on the middle ring the chainline should be straight. If it deviates, it's not setup right.<<
    Exactly! In Stock condition this was WAY off. The mechanic, Zack, pointed this out with a tool that showed how off it was. This is why I opted for the adjustable BB and pulled it closer to the frame for alignment purposes.

    Summary – Ten years of riding a $100.00 bike and never broke anything or dropped a chain. Six months of a $2500 bike and I can’t keep the chain on. I do like the Specialized Expert SJ except for the one problem I have. This brings me back to the question – Is the chain drop to bottom bracket common for full suspension rides or just a Specialized problem? I still would not mind spending a few extra for whatever parts I may need to get this up and going but not much more. I would rather buy another brand stock if the ride doesn’t have the chain drop characteristic.

    Thank you great riders of MTBR.

  6. #6
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    It's definitely not a specialized problem because none of the 5 I own (including 1 04 SJ FSR) or 3 I've own previously have had this problem. Just because 5 mechanics looked at it doesn't mean those 5 mechanics actually know anything about this problem. It's been my experience that the level of expertise in bike shops varies widely. I'm starting to wonder if the frame isn't out of alignment. Try switching to a sram chain. I realize this isn't a chain problem but I don't run shimano chains for several reasons, this might be another. Did you check all the other things that Maestro pointed out?

  7. #7
    Maestro
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    Stanomatic,
    I have owned a Giant VT, an NRS and now the SJ FSR. All of my full suspension bikes tend to drop the chain more often than my hardtails (Klein Attitude & SJ M2). Might have something to do with the length of the chainstays, might have to do with the pivot location as well. (Hardtail vs Full suspension)

    I checked the Specialized specs and the Stumpjumper Elite, Expert, Comp and Pro all list 50mm chain lines.

    According to my older Shimano XT Literature, A 118mm spindle gives a 50mm chainline. They offered a 113mm Spindle for a 47mm chainline as well.

    Could this be an option?

    What chainline does the Truvative offer?

    MWard,
    Good catch on the 34 tooth cassette. I use the 34 tooth cluster for that little extra oomphh on climbs in the middle crank ring.

    The 34 T cassette will provide a little extra chain tension as well.

  8. #8
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    Something else I just thought of. Look down towards your front derailleur. The cage should be parallel to the chainline. If it's turned so the back part of the cage is closer to the centerline than the front part that could be the problem.

  9. #9
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    I have a 04 Stumpjumper and my chain sucks all every once in a while. It'll fall off, but it should not be doing it all the time - mine does it every 8-10 rides.

    I'd say something isn't right...

    You should take it back to where you bought it and tell them to fix it. Did you get free service as part of the purchase?

    I'd also think about contacting Specialized - on the phone and discuss the problem with them...


    Quote Originally Posted by stanomatic
    In January I bought a 04 Stumpjumper FSR Expert Disc bike. This was a major improvement over my 10 year old K-mart special. At least I used to think that was an improvement. From day one I have dropped the chain on to my BB. I had my LBS adjust it only to have it drop right after the adjustment. I have had three different shops look at the problem.

    Most of the time it is when I am riding the mountain. After six months of riding the bike and walking on eggshells trying not to hard shift and drop the chain I took it to the pros of CO Sports Garage. They said the drive train is not aligned and sold me an adjustable BB and Truvativ cranks. They adjusted the BB to pull the crank all the way to the frame. Later I took it out on the mountain and the chain dropped yet again.

    I am a runner transitioning to mtn bike racing. I race short track and 15 ? 25 mile mountain bike races. If I can eliminate jamming my chain I can move up the ladder a few notches as the time shows only seconds between riders. I am spending about a minute or so un-jamming the chain every race.

    My question is: Is the chain drop a problem with Specialized bikes or with most FSR bikes? I am considering selling my bike for one that will keep the chain on the drive. Is there an aftermarket product I can purchase to keep the chain on the small ring instead of my frame?

    Stanomatic

  10. #10
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    Original parts

    I am putting on the original parts back on for warranty reasons and some one from Specialized will be contacting me in the next couple of days to hopefully resolve the issue. I will post again after this has been resolve or not resolved. Thanks again MTBR community.



    Quote Originally Posted by round00
    I have a 04 Stumpjumper and my chain sucks all every once in a while. It'll fall off, but it should not be doing it all the time - mine does it every 8-10 rides.

    I'd say something isn't right...

    You should take it back to where you bought it and tell them to fix it. Did you get free service as part of the purchase?

    I'd also think about contacting Specialized - on the phone and discuss the problem with them...

  11. #11
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    jump stop

    I would agree with everyone else here that you shouldn't be dropping a chain so frequently. One product I have used on our road tandem to eliminate this problem is an N-Gear jump stop. It is similar to a third eye chain watcher but is a much sturdier more effective solution. Check out the website and give the guy a call. He has shipped me one before without charging me for it till after I received it and decided it would work on a single road bike that was occasionally dropping a chain. Good Luck.

  12. #12
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    Yeah, definitely let us know the outcome!

    Quote Originally Posted by stanomatic
    I am putting on the original parts back on for warranty reasons and some one from Specialized will be contacting me in the next couple of days to hopefully resolve the issue. I will post again after this has been resolve or not resolved. Thanks again MTBR community.

  13. #13
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    End of story

    Jesse from Specialized authorized Rob from University Bikes in Boulder to take a look at the problem. The BB was in question but that was the correct size. Rob did not like the looks of the middle gear so he replaced the right side crank with a stock crank. He also lowered the derailleur a couple of hairs.

    The test – Heil ranch in Boulder is an easy trail but very bumpy. I hammered on the bike trying to get the chain to come off with no luck. I hard shifted and the chain stayed on. No more taking it easy on shifting. I can ride aggressively with out worrying about the chain coming off.

    I find it odd that at the other shop tested three different cranks with no success. I think I will still use the N-Gear Jump Stop just for a back up.

    Bottom line – 6 mechanics, 3 shops, and four cranks later, I now have a great working bike.

    stanomatic

  14. #14
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    Quote Originally Posted by stanomatic

    Bottom line – 6 mechanics, 3 shops, and four cranks later, I now have a great working bike.

    stanomatic
    Great to hear! No reason to spend that much money and have something that doesn't do what it is supposed to do...

  15. #15
    Maestro
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    Good News!

    I have found many bikes to have the front derailleur mounted too high on the seat tube relative to the chainrings. I thinks S h i m a n o only recomends 1.5mm clearance. Lowering it helped my bike when I was dropping chains.

    Ken S.

  16. #16
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    Quote Originally Posted by Maestro
    Good News!

    I have found many bikes to have the front derailleur mounted too high on the seat tube relative to the chainrings. I thinks S h i m a n o only recomends 1.5mm clearance. Lowering it helped my bike when I was dropping chains.

    Ken S.
    I've noticed the same thing on EVERY bike I've bought. Road,Mtn, Trek,Giant,Specialized they all had it too high for me. The thickness of a nickle (for us yanks) is about right as it passes over the big ring while shifting. I watched a couple of guys in our lbs building up bikes. The derailleur comes at that height and they just leave it there so it ends up being too high.
    What do I want to be when I grow up.....Dead!

  17. #17
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    This shouldn't be rocket science.

    It's not like this is a custom made experimental frame with a mish-mash of parts. At the same time I find it hard to believe that a whole bunch of mechanics can't solve this problem. And, yet, there you are. My thoughts:

    First off, I suspect the low stop screw on your front Derailleur. It may be allowing the chain to go to far to the left. Back it out until it doesn't want to go into the granny anymore and let out the cable enough to let that happen. tighten it again until it wants to go into the granny, then readjust your cable.
    Second, my front derailleur was mounted too low at the factory. Check it's position.It may be the wrong height or not parallel to the chainrings. I know this is obvious but chekc for damaged teeth and ramps. It's free.
    Third, I like the chain length idea.
    Fourth-like, the b-screw tension might be adjusted for more chain tension.

    All the ideas about chainline are good line-of-site checks that will probably reveal no problem.I feel the same way about bent frame ideas. These checks cost nothing.
    Changing to SRAM; don't make me laugh.
    Last edited by Berkeley Mike; 07-22-2004 at 09:18 PM. Reason: spelling

  18. #18
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    Well mister Mike, the sram derailleur keeps more tension on the chain, which is why I recommended it. Don't make me laugh? Is that derision or what? Being from the enlightened state of Kalifornia I understand that you don't know what common courtesy is, so that's okay. If you had read a little further along instead of getting your panties in a bunch to reply as soon as you saw something you didn't like, you'd have read that he's already had it fixed.

  19. #19
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    Sorry, Mward, not my intention.

    It wasn't Sram I wa laughing about it was replacing an entire system and spending lots of money. I really feel for this guy and the approach to the solution seemed chaotic and non-productive which indicated a need to go back to square one. Just because bike shops have worked this problem doesn't mean it has been managed well.
    Like I said, this is not a piece of exotic equipment. There are, roughly, a bazillion examples of this system working well so, as a fundimental position, changng the system, to me, was laughable.
    Sorry I wasn't clearer.

  20. #20
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    Sorry for my umbrage, then. I offered it as an option merely because it is one. If it was his riding style that was causing it, then it was in the realm of possibilty, albiet an expensive one.

  21. #21
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    De nada

    There IS a bit of umbridge in my cletes, though.

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