tjmaxx

I didn't know what to search for, so if this has been hashed out in detail before, just let me know and point me in the right direction.

For the past year, I have been fairly certain that I needed to replace my chain. I didn't. Yesterday, I wrecked because my chain slipped under heavy load, and the pavement decided to say hi. Because of this, I bit the bullet and decided to measure my chain. Sure enough....12 links were 12.25 inches. Way out of spec from what I read.

Visit the LBS, get a new chain and talk to them about gear wear. They don't think it should be an issue (2100 miles on the bike total....about 1000 on my rear cassette--I had it replaced last year).

I spend about 1.5 hours, replace my chain, and fiddle with my rear derailer to get it to shift right. Too late to test ride it, so I did that today after work.

Everything was fine till I got to the smallest gear on my rear cassette/freewheel. Major slippage all over the place. I stop, fiddle with my derailer some more, and still slipp out the wazoo.

I come home, change out my rear tire for one off my wife's bike (way fewer miles...same bike too). I need to tweak the derailer some more, but everything is ok.

An ideas? Is my rear cassette/freewheel toast?

ken cummings

Maybe you can get by with just replacing the slipping cog and the next one or two over. If you do your own work. Otherwise with labor changes at a good shop you could just as cheaply get a new cluster, I would.

_dhan_

check the chain length. the derailleur may not be able to pick up all the slack.

pakole

I personally would replace the cassette. While I do not know the distribution of miles cranked on the different cogs of your bike, but a used chain will accelerate the wear of the cogs. Thus the rest of your cassette may be on its last legs while the small cog is died.

tjmaxx

WhenI put the new chain on, I measured it against the old one. It looked like the new one was the proper length.

I hadn't thought of this before, but could the old chain have streched so much that it may have looked ok when I really should have lost a link?

tjmaxx

Thanks all for the info. I took terrible care of my chain before (n00b, etc....) and I was real worried about that happening. I'm planning on a ride today using the current set-up that seems to work. I'll know in the first block what is going to happen.

Someone mentioned distribution of riding in what gears. Most of my riding is spent in the big ring up front and small in the back. The one that was slipping would have definantly received more wear than any other back there.

operator

That's probably not a very good idea. It's a crosschain combo and wears stuff out really quickly. I don't think there's a way that you could've lost so much that you lost a link.

_dhan_

big front and small back isn't crossed. If you are spending that much time in the big ring-small cog, maybe you need to up your gearing a little so you use more of your cogs. Also, if that's the way you normally ride, it's understandable that the small cogs have gotten worn out since 1) there's less teeth so they wear faster, and 2) you spend more time in those gears so they wear faster. You can probably just change the smallest cog or two and keep using the rest of your cassette. Look at the shape of the teeth to see if they are worn.

tjmaxx

I suppose I should mention that I have a cassette (is that right) that you purchase as one unit. it has the freewheel, etc... everything all together.

It is on a mountain bike that I ride solely on the road. I have asked many places if I could get higher gears....everyone tells me no can do b/c everyone is going away from these. Do you guys have any extra special "internet" info or sources I could look at?

mayukawa

Have you checked to make sure the guide pulley isn't too close to the small cog? And try adjusting the B-tension screw if necessary?

tjmaxx

Thanks. I'll check that out.

Oh, on my ride Sat, I didn't experience slipping using the configuration described above except on one climb. This was on about a 35-45% slope (yes, it was steep...so steep that walking up it would be tough).

Edit -- After looking this up in my Zinn book, this seems extremely likely to need adjustment. I remember looking at it and wondering "is that all the chain that is supposed to wrap around there?