Drivetrain Help... New set up or Tune-up???

Discussion in 'The Workshop' started by STEALTH91, Feb 17, 2015.

  1. STEALTH91

    STEALTH91 New Member

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    Hwy Party People, I've been having some trouble with my gears lately. My chain keeps trying to jump back and forth between gears while I ride, especially under load. Sometimes, even gets stuck... I've tried dialing in the shift points and it'll help for a ride or two, but eventually it goes back to the same problem. This mostly happens under load, so I can't really mimic the issue while the bike is on a stand...
    Will a pro shop tune up fix this, or do I need a new drivetrain (Crankset, cassette, derailleurs, shifters and chain)? I've had the bike for 10 years or so, so I wouldn't want to dump a whole lot of money into it... but I'm also not planning on getting a new bike anytime soon...
    Thanks for the help...
     
  2. mtnbikej

    mtnbikej Well-Known Member

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    Could be a bent derailluer hanger.....or, most likely sh*t is worn out...10 years is a long time.
     
  3. xtremeMTB

    xtremeMTB Member

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    sounds like it could be the tension of the derailleur cable being loose from time I would swap out the derailleur cable to see if it fixes that.
     
  4. bing!

    bing! Active Member

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    This could be caused by a few different issues.

    First measure the chain for stretch. http://www.kronowit.com/bicycling/chainstretch.html , while at it, check the drivetrain for wear. Unless the gears look like draculas teeth, it's very seldom chain, cog or ring wear will cause slipping under load. But you'll wanna fix these before further testing.

    Second, on an indexing drive train, determine that you have the limits set and that the shifter is in sync with the position of the chain on the cassette. If not, check cable tension, cable housing routing, and cable condition. With that issue eliminated, check hanger alignment.

    Lastly, if the first two checks pass, your freehub may be slipping and require service or replacement.

    Hope that helps.
     
  5. doublewide

    doublewide Ride Life....Ride GIANT

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    Check the chain with one of these specialty tools!

    [​IMG]
     
    Last edited by a moderator: Feb 17, 2015
  6. bing!

    bing! Active Member

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    Hahahah, I still use that :)
     
  7. STEALTH91

    STEALTH91 New Member

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    Thanks for the tips, I'll try those before looking into new drivetrain...
     
  8. skyungjae

    skyungjae Member

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    When was the last time you replaced your cassette and chain?

    The two times I've had a similar experience on older bikes, the cassette and chain were worn out.
     
  9. jeffj

    jeffj Bloated Mountain B'hiker

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    Look straight down at the cassette from above in any gear except the first or last. You should see that the top jockey wheel on the derailleur is directly in line with the cog on the cassette. If it isn't, use either the adjuster on the derailleur (if it's a Shimano), or the adjuster at the shifter, to make it so it does line up. It should run quieter when adjusted properly as well.

    The next thing I would check is chain wear. At 10 years old (and you haven't mentioned if the chain has ever been replaced), I would suspect possible chain wear. Also check each link to make sure you don't have a stiff link, or that any of the link plates are bent. To check for bent link plates, fold the chain link over on itself and see that it lines up with the adjacent link plates. If you don't have a 'chain checker, you can either have a shop check it with theirs, or you can measure it yourself. the links are 1/2" between pins. If you measure 12 inches of chain, the pin at the 12" mark should be more than 1/16" away from 12". If it is, replace the chain.

    If you do replace the chain yourself, you'll need to use a chain tool to push a pin out to make the chain the same length as the original. If you use a shimano chain, you'll either need to push the new pin in to connect it, or purchase a quick link at an additional cost to you (if you have an 8 speed, quick links won't work on a Shimano chain - they're a tick too wide). I'd just get a cheap SRAM or KMC chain as they come with a quick link.

    If it's not those things, then I'd start looking for a bent hanger, cassette wear, chainring wear, gunked up cables/housings, etc. But, IMHO, it's no use looking at the other stuff if the above isn't verified to be OK first.
     
  10. dcrfx

    dcrfx Member

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    Another easy and relatively cheap thing to do is replace the der housing along with the cable. Housing can wear out along tight bends and get sticky causing weird shifting like you describe. If your bike is full suspension, loading the susp could cause the housing bend to change causing the stick only while riding but not when uncompressed on a stand. Very least you can spray some lube into the housing or twist the housing 180 degrees where the bends are so the cable runs on a different part of the internal housing that's not worn. Good luck.
     
  11. skyungjae

    skyungjae Member

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    sounds like new bike time. jk
     
  12. STEALTH91

    STEALTH91 New Member

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    Hey guys, been a while. So I did all the dialing in, and the der is lined up properly. Haven't replaced the cable, I might try that next. But I did take it into JAx in HB and they said it looked good to them. Is there a bike shop you would recommend that can give me an honest diagnosis? I'm in North OC. oh, and none of the drivetrain has been replaced. It's an '07 Gary Fisher HiFi Deluxe:
    Drivetrain
    Shifters

    Shimano LX

    Front derailleur

    Shimano LX

    Rear derailleur

    Shimano XTR

    Crank

    Shimano LX 44/32/22

    Cassette

    SRAM PG970 | 9 speed
     
  13. un-kola

    un-kola Just another Homer!

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    Try Fullerton Bikes I believe on Commonwealth or the Path in Tustin. - Lloyd
     
  14. MnMDan

    MnMDan Member

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    IMHO, it sounds like it should have the drivetrain and cables replaced. Its probably been ridden enough that replacing one item might resolve the issue, or it simply may resolve its contribution to the issue. It'd be frustrating to replace something only for the problem to come back. Cassette, chain, cables/housing. Replace them all. Crankset chainrings are probably fine. I'd also have the shop you use (use the one most local to you that you feel comfortable with) for this service check the suspension pivots. They should all be in good shape, but they should also be checked every couple of years (or sooner with hard riding).

    Its a relatively inexpensive way to go, and that bike is a pretty solid foundation. It'll accept replacements and upgrades as long as you want to keep riding it.
     
  15. nailknot

    nailknot Member

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    Replace HOUSING and cables. Over time the reinforcing wires that run internally inside the housing begin to poke out and the end of the housing. You can't see this as its under the ferrel. Ive replaced dérailleur aand chains also but didn't fix the problem. A buddy said check the housing, sure enough. Housing was bad
     
  16. STEALTH91

    STEALTH91 New Member

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    So I took it into The Cyclery Bike Shop in LA Habra. They seemed to be pretty honest, and didn't try to "up sell" me on replacement parts. I'm getting a new crank, cassette, and chain, as well as a tune-up. Hopefully this will get me back on the trials with more frequency... Fully Loop, Here I Come...
     
  17. da big hills

    da big hills happy night trails

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  18. Congo Kid

    Congo Kid Middle Aged Wannabe MTB'r

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    Here's a question: I just took the plunge from my 26 inch Stumpy to a 27.5 inch with 2 X 10 drivetrain. I feel I've lost a granny gear. 26 in front and 36 in rear is the current XTR configuration.
    I've been told to look at a "one-up" kit that would require extending the cage a bit and swap out 1 gear in the middle of the cassette for me to have a larger granny gear in the back. Alternatively, someone said to just get a 24 tooth small ring in the front to replace the current 26 tooth ring. A friend who did the 24 tooth swap out was told that his gears would have issues with shifting, but so far that has not happened.

    Any recommendations on which route might be best?

    Thanks,
    JEFF
     
  19. irv_usc

    irv_usc Active Member

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    Depending on who you ask, the extra granny kit from oneup or the others may or may not shift as well as stock.

    It would probably be easier to find a front 22t or 24t to replace your small ring and leave everything else as is. If your crank is the current XTR, I don't see why getting the 24t from the 24-34 set wouldn't work.
     
  20. da big hills

    da big hills happy night trails

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    Not enough info since you did not describe the stump jumper. That aside. A 27.5 wheel is larger in dia than a 26, thus even with the same exact gears you would have a bike that climbed more like a 34 or 32 tooth. The affect is even greater when going to a 29er. Simple physics, the laws of physics shall not be violated even if the 2016's are on the market.

    Regardless, um irregardless, regardless, just making a larger jump to the big ring will make it harder for the chain to climb into the big ring and can lead to dropping the chain when down shifting.

    It is one of the design flaws of the 27.5 and 29.

    You can always go up to 42 in the back and loose some chain combos even with a long cage RD but you should not cross chain anyways.

    Everyone I know that has increased the rear has complained about shifting and such, but they have all kept the combo and just given up on big ring-big cog and small ring-small cog combinations .
    Happy modern technology trails
     

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