1. The most important thing about buying a new bike is to make sure it fits. The only way you'll know if the bike is right for you is to size up the bike and make sure that the bike's geometry matches your body's geometry. Ask questions and do some research.
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2. If possible, try to find a shop that will let you demo the bike on real dirt. Five minutes in a parking lot won't cut it. You wouldn't buy a car without a real world test drive, and a bike should be no different.
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  1. #1
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    Chain skips when applying a lot of torque on Giant Yukon FX

    I got a new bike last year (Giant Yukon FX) and whenever I apply a lot of force like to accelerate or go up hills on the fastest speed on both front and back the chain almost always skip.

    I know it's not really normal to be on the hardest possible speed to go up hills but I have strong legs and I'm used to it from my old bike which was cheap and didn't have this problem.

    Could it be because my new bike has a higher top speed ratio (the rear high speed gear is absolutely tiny)? Or is it because I'm asking too much out of the transmission for the top speed? Or is it a defect?

    I wish I could get this fixed, but if it's just that it's because I shouldn't apply so much force on the top speed then I'll try to learn to go to lower speeds when accelerating and going up hill, but honestly this is the kind if problem I'd expect from a $100 bike, not from a $1200 bike, so I hope there's a solution.

    Thanks
    Last edited by ch2s; 04-15-2010 at 01:50 AM.

  2. #2
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    Just to clarify, the chain isn't coming off needing to be repositioned, what happens, at least what I think without seeing it, is that the chain skips over the teeth on the rear gear which makes a noise and the pedals give a kick of free turning for a fraction of a second as the chain skips over the teeth and back onto them.

  3. #3
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    funny you mention this cause my bike does it too if im climbing on a high gear, im guessing its time to adjust the rear derraillure again
    2009 Giant Yukon FX

  4. #4
    local jackass
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    i would say derailer adjustment aswell as possiablly a rear cassette or chain i bought my bike brand new and after 2 months for some reason it needed a new cassette to solve my skipping problem
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  5. #5
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    i had a similar problem and it was because my chain had gotten muddy and wet and then never cleaned properly. i cleaned it and oiled it and the problem went away completely

  6. #6
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    My bike needed the rear cassette and the chain replaced after about 400 miles. She always skipped in the middle chain ring in the front and the smallest on the back. LBS replaced both and problem solved. Well it's back this year and once again I'm at 400+ more miles. Chain checks out fine for stretch. I would check the chain and cassette.

    On mine if I move to the big chain ring in the front my chain skip disappears so it could be cranks on mine as well but no it's not normal.

  7. #7
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    Quote Originally Posted by ch2s
    ...whenever I apply a lot of force like to accelerate or go up hills on the fastest speed on both front and back the chain almost always skip...I know it's not really normal to be on the hardest possible speed to go up hills but I have strong legs...if it's just that it's because I shouldn't apply so much force on the top speed...
    I think you should seriously consider converting your bike into a single speed. It looks like it might be right up your alley.

  8. #8
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    Does it skip every three or four turns of the crank? If so, check for bent links in the chain.

  9. #9
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    Quote Originally Posted by jogden
    Does it skip every three or four turns of the crank? If so, check for bent links in the chain.
    No, it seems completely random and normally only when applying a lot of force, and some times when I'm applying a lot of force I think it's going to skip and it doesn't, so it's a bit unpredictable but normally only when under high force.

  10. #10
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    try to check of you are getting ghost shifting from the cable being pulled when the suspension is compressed.

  11. #11
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    Is your rear derailleur hanger bent?
    Have you tweaked the barrel adjuster for your rear derailleur?

  12. #12
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    Sorry wrong forum
    Last edited by john.wilkinson@datacon.at; 04-15-2010 at 11:06 AM.
    26FS & 29Rigid... best of both worlds

  13. #13
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    If you bought the bike last year and have ridden it a lot, it is quite possible that you've worn the drivetrain pretty thoroughly. If you're positive that the derailleur is adjusted correctly, your chain is not bent, everything's lubed and in proper working order, the cassette is tight (a loose cassette can move under severe load and cause skipping), and you're not getting ghost shifting under suspension compression - most of which were mentioned above - then have a shop check your chain/cassette/ring wear. A stretched chain usually doesn't skip on the original cassette because the cassette's worn in with the chain - but an extremely worn drivetrain will always act funny if it's bad enough. Good luck!
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  14. #14
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    Quote Originally Posted by john.wilkinson@datacon.at
    I ride near Philadelphia and its a very mixed crowd. I've encountered many nice helpful people on the trails and some @$$ holes that scream stupid things as they go by and act like they have the right-of-way no matter what.

    Worst was when I was riding with my wife and she can't do many of the hills I have no trouble with, so I'm walking them with her for moral support and some jerk screams "you guys need to learn to ride" If I had a stick it would have been in his spokes.

    Now that I ride a low-end rigid MC29er, I especially grin, smile and say hello when I pass someone on their high-end 26FS. If nothing else their mouth is usually wide open.
    I'm not quite sure what this has to do with the OP lol

  15. #15
    pants on head retarded
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    Watch your chainline - Bikes don't have 27 speeds so you can increment up them one at a time like you do in a car. They have 27 speeds so you can move your entire chain side to side to keep it in a straight line front to rear. If you're in a harder gear, I expect you'll be somewhere around big in the front and little in the back? If you're big in the front and somewhere in the middle in the back, switch down to middle in the front to try and keep your chain in a straight line. There is an awful lot of overlap in your gearing so that you can keep your chain straight.

    If your chain is running straight you could have a mechanical issue. As mentioned above, by riding in a hard gear and really pumping the pedals you are putting a great deal more torque and strain on your drivetrain. The result is that your chain will stretch quicker and your cassette and chainrings will wear faster. Also, if you're replaced any one part of the chain system (cassette, chain, or chainrings) without replacing it all, you could have worn parts meshing with new parts which most assuredly would cause skipping. The new parts expect an exact distance between chain links - if the old parts are worn this will be longer.


    And lastly - is the FX a full suspension bike? Some FS bikes suffer from something called "chain growth" where the distance between the rear axle and the bottom bracket changes slightly when the suspension is active. Putting a lot of torque into the system and then changing the effective distance the chain needs to cover could be causing some ill effects that you wouldn't see in a hardtail.

  16. #16
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    By having the front gear on the biggest (outer most) gear and rear on the smallest (also outer most) the chain is straight so I don't think that's the problem.

    I measured my chain and it seems to be the exact length it should be. The gears also don't seem to have any visible wear (as mentioned the bike has 1000 km on it which I don't think is that much).

    The only part replaced was the rear derailleur when it got smashed to pieces by hitting a rock. I don't remember if the problem existed before changing the rear derailleur.

    The FX is a full suspension, I'm not sure I understand what you mean by the distance between the rear axle and bottom bracket changes, what do you mean by rear axle and bottom bracket?

  17. #17
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    When I had mine the same happened and I just got the rear derail adjusted and that was it.
    Ride

  18. #18
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    I bought an FX last year and noticed when you spin the pedals backwards it would downshift several gears. I took it to the bike shop where I got it and they couldnt figure out why. They only tried a few things and since Giant said there is no problems with the design and they would not pay for the cost to see if the rear derailure or gear set is not right for that bike my bike dealer made me a deal to upgrade to a Trance X4. After seeing this post I believe that Giant didnt design something right and its less likely that you wore the parts out. Take it back to the dealer or see if they have had similar complaints.

  19. #19
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    Did you purchase the automatic transmission on your bike?
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  20. #20
    pants on head retarded
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    Bottom bracket is where your pedals attach and spin around, rear axle is what your rear wheel spins around. In a hardtail bike these two points are always the same distance apart (save some mostly negligeable frame flex). In many full suspension layouts, they will move relative to each other as the suspension squishes. This *could* be an explanation why you'd see it on this one but not an older hard tail.

    As previously mentioned though, get your derailleur checked out - I think I'm just leading you on a tangent here :P

  21. #21
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    [QUOTE=ch2s]
    The only part replaced was the rear derailleur when it got smashed to pieces by hitting a rock. I don't remember if the problem existed before changing the rear derailleur.
    /QUOTE]


    Ummm...your derailleur hanger is bent. If "the rear derailleur when it got smashed to pieces by hitting a rock."....you probably also "smashed" your hanger. If the bike doesn't have a hanger, your dropout is bent.

  22. #22
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    If it's a year old and you've been riding, you could very well be due for a new chain. Measure it.

    http://www.sheldonbrown.com/chains.html#stretch
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  23. #23
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    Quote Originally Posted by Brujo
    funny you mention this cause my bike does it too if im climbing on a high gear, im guessing its time to adjust the rear derraillure again
    cable

  24. #24
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    My buddy has had this bike for two years and his FX just started doing the same thing, it's not a design issue, it's just wear. He replaced the chain, still not 100% right, say it needs a cog also, make sure you really clean " pick up some degreaser ", check for bent links and relube chain and check adjustments before dropping you're coin on new parts. Good luck

  25. #25
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    did OP every find out the issue? I just degreased the chain and rear cassette. Relubed and still same problem but not as bad. The rear hanger was a tad loose and i retightened. This only happens in gears in middle of the cassette and doesn't matter what ring I'm in. New cassette time...or entire rebuild kit and use the leftovers to build the SS!

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