bklyn74

I've thrown my chain 4 times or so in the past couple weeks but my chain tension is fine. Could a worn out cog cause this? Thanks.

dutret

Perhaps but unless there is a lot of visible wear you should check everything else first.

Gyeswho

chainline might be off

captsven

Have you ever checked your chainline with a straight edge?

Has this just started recently? If so how long did it go w/o throwing a chain?

bklyn74

It just started recently. I've been riding the bike for about three years w/ no problem. It occurs to me I had the hub rebuilt about a month and a half ago so maybe the wrench forgot to put a spacer back on or something. But even so it's really just started happening in the past couple weeks. I took a good look at my cog and it's pretty dirty so maybe a good drivetrain cleaning will get it sorted. I'll also check the chainline. Thanks for the input!

Gas.Face

If you have recently replaced or reinstalled your chain, the problem could be caused by a stiff link. I threw my chain for the first time a few weeks ago because of this.

captsven

Three years w/o any chain/cog change seems a long time. I guess it depends on how many miles you ride, chain tension and chain maintenance.

My guess would be you need a new chain and cog. If it gets worse as you apply more torque on the pedals, it is a worn chain and/or cog.

Rebuilding a hub should have no effect on your chain line. But, the wrench could have put the cog on opposite of how it was originally put on. They could have also accidentally respaced the hub when they reassembled it. These are both long shots and any decent wrench would not **** this up.

bklyn74

The front chainring and chain are about a year old, the cog is older. I'll probably put a new cog on the back and see how that goes. Thanks again.