john56

I am having several problems with my drive train. I will do my best to explain this but if any clarification is needed please let me know. I am basing several of my observations off of my riding buddies bikes. This might be one large problem or several small ones so I will list them separately just in case.

The Bike: Specialized Roubiax- Brand new chain ring, brand new chain. ( replaced in hope of solving issues.) Shimono 105 components. 10 speed triple

Problem one: I can not pedal backwards without the chain falling off. ( riding buddies can do this) I know it serves no purpose but the chain should not be falling off.

Problem two: My chain rubs the inside of my front derailleur. It does it on all of the gear expect for a few in the middle. I have attempted to adjust the screws with no success at all.

Problem three: Shifting and drive train sound horrible.


I have taken the chain rub issue to my LBS and they brush it off as your not supposed to ride in the gear combo. but again my riding buddies can with no issues at all.


What suggestions do you have ? I would like to avoid have a 200$ rebuild done at an LBS to try and fix the problem.


Thanks for all of your help.

Andrew R Stewart 

As you suggested it seems that you might have a few issues so i say that you try to fix them as separate ones.

Chain rub is possible the easiest so tackle it first. A full base lining of the ft der's adjustment, cable condition and attachment would be my approach. It's possible that chain ring condition enters as in bent/wobbled rings but worn teeth usually don't contribute to rub.

Shifting and chain running could be explained by a worn out cassette and new chain. Are you sure the new ring is properly mounted too? Worn out upper pulley, lots of cable friction can add their aspects and make clean shifting and after shift chain running hard to get.

Chain drop off while pedaling backwards can be a number of factors. You say that the shop suggests that you stop using certain cog/ring combos, Are these the cross over ones? if so the STOP using them. Bent teeth, twisted links, too much friction in the freehub body's bearings are all first line possibilities. Worn rings, excessive play in the BB bearings/loose cranks. One has to find a way to consistently repeate this when able to observe then match up conditions with the chain fall off.

Often at work when we see a slue of problems and lots of age/wear we suggest a number of replacements at the same time. usually this and "behind the scenes" servicing makes the problems go away. You really need to have an experienced and motivated set of hands touch your bike. Andy.

cny-bikeman

Problem one: You are not necessarily in the same gear as your buddies, and there are other possibilities, including bent chainrings, too much friction in the freewheel/cassette, stiff chain, etc. You need hands-on, in-person to determine the problem.

Problem two: "attempted to adjust the screws" does not tell us whether you just fiddled with them or used a good source of info such as sheldonbrown.com or parktool.com/blog. You need to follow each step, and cable/housing friction can also be a factor.

Problem 3 - need to address problem 2 first - including lubrication of the drive train, of course.

I suggest you find a more knowledgeable friend to help, or a bike co-op if one is available - can't tell as you did not specify your location.

Retro Grouch 

Try this first:

1. Shift your bike into a gear that makes your derailleur arm point straight down.
2. Prop your bike up against something and look at it from the back.
3. If your derailleur seems to be pointing toward the rear wheel - that's it.

Bent derailleur hangers are common.