Bicycle Mechanics - chain in spokes?
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06-05-07, 11:20 AM
On my ride yesterday in pouring rain we were coming up on a stop sign and I downshifted ... I was in the big ring and didn't realize I was getting crosschained. This made the chain drop off the big ring and it dropped all the way off to the inside. I've had this happen a couple of times before ... no biggie just push the fd back up and it gets back on (TruVatuv Rolleur/campy veloce fd) But this time I guess it pulled the chain off the cassette and into the spokes too. I heard the non normal grinding and got on the brakes just before the rear wheel locked up. Skidded/fishtailed to a stop keeping everything upright. Chain was wrapped pretty tight around spokes, I was able to free it back up with some effort and ride back home. Noticed my up shifts were slightly off. (campy centaur rd)
Got home and checked it out ... scratches on a few spokes/ one spoke definate bend where is goes in the hub (Campy Zonda's) No noticable rd damage, some scratches on a few chain links but no binding.
I've done spoke replacements before, but do you think I should take it in and have rd alignment checked too? I would think all the limit screws are set OK as drivetrain has 3500 on it. Only time I get the chain drop issue is getting crosschained with some load on it? Suggestions?
I would have the rear wheel checked carefully and have someone set of the rear limit screws properly. The fact that this has happened before suggest something is amiss.
But this time I guess it pulled the chain off the cassette and into the spokes too...
I would think all the limit screws are set OK as drivetrain has 3500 on it.
I don't think these two statements belong together.
Also, stop using cross combinations.
06-05-07, 11:30 AM
06-05-07, 12:10 PM
Yeah, I try not to get cross chained ... but sometimes I just hit the downshift and and don't notice the 23 is the next cog.
It's never come off the rear cassette before ... just the front big ring. And even then it doesn't happen on a fd shift, just when I get cross chained big/big. Does that indicate a limit screw issue?
06-05-07, 02:38 PM
If the chain goes into the spokes, IT IS a limit screw issue. Screw the L limit screw ina 1/2 turn or so.
06-05-07, 04:05 PM
Got home and checked it out ... scratches on a few spokes/ one spoke definate bend where is goes in the hub (Campy Zonda's)
I'd strongly advise pulling your cassette to check the spokes. I'd be surprised if all of the outside spokes on your drive side hub flange aren't buggered up.
06-05-07, 04:58 PM
If the chain goes into the spokes, IT IS a limit screw issue.
Sorry, not true and not the proper solution. It is clear from the explanation that the problem in the rear was initiated by the front unshipping. Makes perfect sense, as the pulley assembly would have whiplashed due to the absence of chain tension. Absolutely have the derailleur hanger alignment checked, replace any drive side spoke showing damage. Also after the hanger alignment is correct rotate the derailleur on the main pivot to see if the angle of the pulley assembly changes (should stay close to parallel to the wheel). Of course the front and rear derailleur adjustment should be checked as well.
As for the front unshipping when going to cross chain that may be hard to avoid depending on many factors alone or in combination. Some combinations of short chainstays and 9/10 cog cassettes, especially if the alignment between chainwheels and cogs is a bit off (cogs too far inboard) can be very problematic. It's admittedly hard to remember where you are in gearing with STI shifting - in the old days shift lever position would tell you.
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