New bike, bent chainwheel?
06-28-05, 10:07 PM
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New bike, bent chainwheel?
I finally made the switch from mtn bike a couple weeks ago with a '05 LeMond Reno (double), but theres a grinding sound from the chainwheels that's driving me crazy. Maybe you guys can help me figure this out. Here are the symptoms:
1.) Shifting and trimming from the smaller gear to the larger gear is fine, but trimming from larger gear to smaller is impossible. Even shifting takes much more energy and causes a loud snap when it finally does shift, often causing the chain to completely jump off.
2.) When on the smaller front gear, only 5 of the 9 larger rear gears are usable before a grinding sound starts. After a lot of playing around I've found that the grinding is from the chain rubbing against the larger gear in one spot. If I shift to the 3 smaller rear gears the chain actually gets caught against the side of the larger front gear and pulled 1/3 a turn around before falling back on the smaller gear.
There is no visible bend to the front chainwheel but I can't think of anything else that would cause the grinding. Given that its a new bike, should I just take it back to the store?
1.) Shifting and trimming from the smaller gear to the larger gear is fine, but trimming from larger gear to smaller is impossible. Even shifting takes much more energy and causes a loud snap when it finally does shift, often causing the chain to completely jump off.
2.) When on the smaller front gear, only 5 of the 9 larger rear gears are usable before a grinding sound starts. After a lot of playing around I've found that the grinding is from the chain rubbing against the larger gear in one spot. If I shift to the 3 smaller rear gears the chain actually gets caught against the side of the larger front gear and pulled 1/3 a turn around before falling back on the smaller gear.
There is no visible bend to the front chainwheel but I can't think of anything else that would cause the grinding. Given that its a new bike, should I just take it back to the store?
06-28-05, 10:10 PM
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uh... it is simply not properly adjusted
also - ideally you're not supposed to ride in the big-big combination and small-small combination
also - ideally you're not supposed to ride in the big-big combination and small-small combination
06-28-05, 11:13 PM
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You are right to ask, all part of the learning process. I had the same issues when I got back into cycling.
ShinyBaldy is right in that you shouldn't "cross-chain" which is where you are on largest/smallest, smallest/largest combo. This stresses the drive-chain and there will normally be rubbing somewhere in these combos.
The chain snapping back from largest/smallest is a cable adjustment issue, likely too tight. Check to see that when you are fully clicked on the smaller chainring, that you cable has little or no tension on it. In any case your bike store can quickly tune it for you. While you are there, you might want to ask them to demonstrate shifting technique.
You can also look at buying something like a dog-fang chain keeper, a small device that bolts on to your downtube which stops the chain from falling off the small ring. This will save smome grief & some wear & tear on the frame chainstay & chain.
Nice work, hope you enjoy your new ride, no dounbt you will have a brace of new questions over the next few weeks. Searching the forums is a good idea as most of these questions have already been asked/answered in the past, this forum is a good store of collective knowledge. Good luck.
ShinyBaldy is right in that you shouldn't "cross-chain" which is where you are on largest/smallest, smallest/largest combo. This stresses the drive-chain and there will normally be rubbing somewhere in these combos.
The chain snapping back from largest/smallest is a cable adjustment issue, likely too tight. Check to see that when you are fully clicked on the smaller chainring, that you cable has little or no tension on it. In any case your bike store can quickly tune it for you. While you are there, you might want to ask them to demonstrate shifting technique.
You can also look at buying something like a dog-fang chain keeper, a small device that bolts on to your downtube which stops the chain from falling off the small ring. This will save smome grief & some wear & tear on the frame chainstay & chain.
Nice work, hope you enjoy your new ride, no dounbt you will have a brace of new questions over the next few weeks. Searching the forums is a good idea as most of these questions have already been asked/answered in the past, this forum is a good store of collective knowledge. Good luck.
