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  1. #1
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    rear wheel eating up derailleurs :/

    ychhh last weekend was ride ended up terribly...

    I smashed my rear der. - for the third time in 3 months.... I'm depressed... The first time it was a thick stick caught in spokes, which ripped the der. away. The second time, I used the lil bit bent der. from the first accident, I guess it had too much play and fall into spokes when I was trying to do tabletop... But this time it was a brand new der. and no stick... it's the worst thing that I don't know what happened - it was on a rooty section and I was in 4th or 5th gear and the der. fell into the spokes...., maybe I didn't adjust it correctly?

    any insight on that?
    Passion beyond reason!

  2. #2
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    I've no idea what happened ... maybe you forgot to tighten it up properly .... maybe the root fairy's got fed up with all the noise

    Have thought about getting one of these to reinforce your mech ?http://www.on-one.co.uk/index.php?mo...sition=233:233

  3. #3
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    Quote Originally Posted by goRz
    ychhh last weekend was ride ended up terribly...

    I smashed my rear der. - for the third time in 3 months.... I'm depressed... The first time it was a thick stick caught in spokes, which ripped the der. away. The second time, I used the lil bit bent der. from the first accident, I guess it had too much play and fall into spokes when I was trying to do tabletop... But this time it was a brand new der. and no stick... it's the worst thing that I don't know what happened - it was on a rooty section and I was in 4th or 5th gear and the der. fell into the spokes...., maybe I didn't adjust it correctly?

    any insight on that?
    maybe you didn't adjust the inner and outer stops correctly (there are tiny screws on r. der that adjusts when the derailleur stops in it's travel, it should stop just below the largest and smallest cog and go no further even if you still have cable pull). If this is not adjusted correctly, overshifting can drive the r. der into the spokes. Either that or your derailleur bolt broke.

  4. #4
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    Maybe this is a stupid question, but did you replace/check your hanger after each of these mishaps? Even if it looks okay, being a bit out of whack or even just loose can be enough to snag the derailler in the spokes. One of those Park tool thingys will tell you in a jiffy if the hanger is bent.

  5. #5
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    Quote Originally Posted by budgie
    Maybe this is a stupid question, but did you replace/check your hanger after each of these mishaps? Even if it looks okay, being a bit out of whack or even just loose can be enough to snag the derailler in the spokes. One of those Park tool thingys will tell you in a jiffy if the hanger is bent.
    yup I used new hanger every time, they were broken or bent too much to use again.

    I think I might have forgotten about adjusting the screw responsible for the reach beyond the biggest cog, but that shouldn't matter as I was in 4. or 3. gear at least.

    hmmm still don't know what to think about it... hope it was just a mishap.... and won't happen again...

    BTW. SRAM rear der. users did you notice that while going through very rough sections SRAM rear der. tries to change gear (to the bigger cog) itself ?? Or is it just my bike ??
    Passion beyond reason!

  6. #6
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    Quote Originally Posted by goRz

    BTW. SRAM rear der. users did you notice that while going through very rough sections SRAM rear der. tries to change gear (to the bigger cog) itself ?? Or is it just my bike ??
    your cable housing maybe too short causing ghost shifts as the suspension compresses. i had this same issue on a mantra i have... your cable only need to move a few mm to execute a shift...

  7. #7
    jna
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    Quote Originally Posted by goRz
    ychhh last weekend was ride ended up terribly...

    I smashed my rear der. - for the third time in 3 months.... I'm depressed... The first time it was a thick stick caught in spokes, which ripped the der. away. The second time, I used the lil bit bent der. from the first accident, I guess it had too much play and fall into spokes when I was trying to do tabletop... But this time it was a brand new der. and no stick... it's the worst thing that I don't know what happened - it was on a rooty section and I was in 4th or 5th gear and the der. fell into the spokes...., maybe I didn't adjust it correctly?

    any insight on that?
    I had the same thing happen twice on my 575, it was a root that was running at about a 15 degree angle to the trail on a steep climb. There was a large rock on the left side of the trail that forced you to veer right and the root was there waiting for the rear der, it pushed it in the spokes and since I was standing and hammereing the der made it all the way to the 12 o'clock position on my wheel. I made it a singlespeed for the two mile ride back. I replaced the der, and hanger and three weeks later did the same thing at the exact same place on the trail and said very bad words in front of my wife. I have been riding that trail for two years and it never happened, so I think that maybe trail erosion made the root just a little higher this year.

  8. #8
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    Quote Originally Posted by goRz
    BTW. SRAM rear der. users did you notice that while going through very rough sections SRAM rear der. tries to change gear (to the bigger cog) itself ?? Or is it just my bike ??
    The cable/housing suggestion is a good one, but even with new stuff installed to the right length, I've traced this problem to the B-tension bolt (or whatever SRAM calls their version of this). The manual calls for 6mm of spacing from the derailleur pulley to the cassette teeth, and in my experience it's pretty important to stick close to that otherwise I get skipping. This bolt never seemed to have the slightest effect on Shimano systems ... go figure.

  9. #9
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    Quote Originally Posted by budgie
    The cable/housing suggestion is a good one, but even with new stuff installed to the right length, I've traced this problem to the B-tension bolt (or whatever SRAM calls their version of this). The manual calls for 6mm of spacing from the derailleur pulley to the cassette teeth, and in my experience it's pretty important to stick close to that otherwise I get skipping. This bolt never seemed to have the slightest effect on Shimano systems ... go figure.
    hmm housing seems to have proper length but I'll check that.
    This B-tension bolt is the small one clse to the hanger, isn't it? I've heard it's important to set it correctly, but I didn't know what the spacing should be. So it's 6mm between der. upper roller and the smallest cog in the casette (in fact it will be 6m no matter which cog, right?) ? I'll have to check that too.
    Passion beyond reason!

  10. #10
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    Quote Originally Posted by goRz
    yup I used new hanger every time, they were broken or bent too much to use again.

    I think I might have forgotten about adjusting the screw responsible for the reach beyond the biggest cog, but that shouldn't matter as I was in 4. or 3. gear at least.
    if somthing bumped the derailleur, the low limit might have stopped it from getting in the spokes, then again it might not have. if somthing weird happened, somthing yanked the cable somehow, the limit certainly would have saved your derailleur. If this is happening a lot you might consider one of those plastic spoke-protector things. I know they are so unfashonable, but IMO walking home because your bike broke is moreso.

    Quote Originally Posted by goRz
    BTW. SRAM rear der. users did you notice that while going through very rough sections SRAM rear der. tries to change gear (to the bigger cog) itself ?? Or is it just my bike ??
    Sram rear derailleurs are more sensitive to too-short housings I believe due to the direct cable routing, as opposed to shimano which have the big loop in back (which can take a little of the tug of suspension compression). I'd bet that as your suspension compresses it tugs the cable. You could either make the rear derailleur housing a little longer next time, or if you wanted to be really anal next time you measure out housing disconnect one of the ends of the rear damper, fully compress the rear end (removing the damper so you can leave it like this), turn the handlebars all the way away from the cable guides. That way you'll know the housing is long enough.

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