Chain Help Plz
Thread started by kaslik
at 01.30.09 - 1:08 am
I've been having trouble with my chain as of late, and finally on my last ride someone took a look at it and pointed out something to me.
When the drive train crank is at 9 o'clock the chain is looser, and when that same crank is at 3 o'clock it is much tighter. He suggested to me that my bottom bracket may be spinning off center. It isn't the chain ring, I just bought a brand new one.
Any idea on how to fix it? Suggestions?
Thanks in advance
I take it you have a singlespeed or fixed gear drivetrain? The loosey-tightey thing is actually pretty common. There's a good chance it's your chainring, and the fact that it's new wouldn't make any difference. A lot of them are slightly out of round; they're not exactly manufactured to surgical tolerances.
01.30.09 - 1:17 am
Also, check Sheldon Brown's site for a technique for adjusting the position of your chainring slightly to offset the imbalance. It involves loosening the chainring bolts a bit and tapping the chain with a mallet.
01.30.09 - 1:24 am
The cogs and chainring do not wear evenly since your leg produces varying power as it rotates. This inevitably results in tight spots in your chain. Depending upon how bad it is, you can adjust it out. If the wear is bad, however, it may just be time to replace your drivetrain.
01.30.09 - 1:44 am
Replace the drivetrain
01.30.09 - 1:47 am
who give a fuck if its looser then tighter. sheldon uses biopace on his fixed gears. i tired it it works, fucking weird though.
01.30.09 - 1:50 am
drivetrain = short for chain, chainring, and cogs. You know, the things that transfer power from your legs to your wheel. Changing a chain without changing the gears it runs on will cause the chain to wear into the shape of the old chain in very short order, cutting the life of the new chain down to almost nothing. Changing the gears without changing the chain will do the exact same thing to the new gears. If you've got significant wear in the drivetrain, you need to replace it all if you don't want to find yourself replacing bits and pieces of it all the time.
01.30.09 - 2:01 am
I do ride a single speed.
I had just replaced the chain ring because I wanted an easier gear ratio. I've only put maybe 300 miles on the bike. The chain seems fine, but I won't take the bike out for a long tide until I get this issue fixed. I'm going to take what was suggested on sheldon's sight and tell my local bike shop that I'd like to have it done.
Thank you for the advice guys.
01.30.09 - 2:24 am
Any chance that chainring you added to your bike was a Shimano Biopace?
Those chainrings were actually DESIGNED to be slightly oval, as that would theoretically make your pedal stroke more powerful, but they were designed for geared bikes where the rear derailer would take up the chain slack, and aren't the best option for singlespeeds.
There are a lot of those chainrings floating around, so there's a slim chance that's the issue.
Take it into one of the bike co-ops (bikerowave, bike kitchen, bike oven) to take a look, or go to one of the shops whose folks post up here regularly (Atomic Cycles, etc.), so you don't find yourself stuck with a whole new drivetrain unnecessarily.
01.30.09 - 8:31 am
you could always get a tensioner. but thats against the hipster rules of style.
are you by chance running brakeless too?(btw, NOT a stupid question)
01.30.09 - 9:47 am
i have a 3/32 sram road chain ill sell you for $5. less than 50 miles on it before i upgraded to 1/8 izumi super toughness.
01.30.09 - 10:09 am