|   XT (RD-M750) Rear derailleur problems... Help please. | Calpolyclimber
Jan 10, 2004 2:50 PM | | I have been riding with very few problems/adjustments for months now, but lately my shifting has been kindof funky... I have been adjusting using the barrel adjuster, and it helps a little, but it is still not working correctly. Just a couple minutes ago I followed Shimano's service instructions word for word and it still isn't happening... It shifts from small to large just fine, but when I try to shift from large to smaller, it grinds, and doesn't shift all the way. I thought it might be dirty cables, but I just cleaned then recently. Any thoughts? Thanks in advance. |
| the First Thing you Always need to check for those problems... | club
Jan 10, 2004 5:56 PM | | ...is alignment of the derailleur hanger. Any shop has the special tool that screws into the hanger and verifies the hanger is straight by gauging off of the rim, and if it's not perfectly parallel, you just gently reef on the tool in various directions until it is. No amount of fiddling will make shifting perfect if the hanger is bent, and it can be bent so little you can't see it's cockeyed without the special tool. It's a tool well worth owning if you work on bikes, but meanwhile, grab a bomber of microbrew and head to your friendly LBS and watch how it's done. |
| Or another possibility(where you don't leave home)... | fred³
Jan 11, 2004 5:59 AM | | is that since the barrel adjusters can't do the job you may need to actually tighten more of the cable than the barrel adjusters are capable of doing. This is accomplished by loosening the cable where it's attached at the rear derailleur. It is a bit more involved than what you've been doing. Since it takes a while to explain properly and there are already books out that do a really great job explaining it I suggest you purchase one(Zinn's is a good place to start). This way even if your computer isn't working you can still fix your bike. |
| Doesn't sound like thats the case... | jcw
Jan 11, 2004 8:32 AM | | since it's shifting in one direction fine, which indicates that there's enough cable pull to do the job. Sounds to me like it's simply sticky cables. A bent derailleur hanger tends to effect shifting in both directions. My guess is a small fray in the cable or a kink in the cable housing. Greasing cables (never a good idea with modern cables and housing IMO) will not fix either. I agree with Club that the first step, regardless, should be to check the derailleur hanger, and if that checks out OK, replace the cable and housing. |
| Fixed... | Calpolyclimber
Jan 11, 2004 1:23 PM | | I had the shop check out my hanger, and it was a LITTLE bit off, so he straightened it (for free). I checked out the cable, and one strand had broken where it is fixed to the derailleur and snaked its way back into the housing. I bought a new cable and just finished installing it. It shifts like a dream. Thanks for the help guys. |
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