# How many kilometers befor change chain and cog?



## PunkOi (Jul 4, 2009)

I thinking to buy ss bike but i wonder on how many kilometers chain and cog wear?


----------



## JCavilia (Sep 12, 2005)

Depends. Varies with riding conditions, maintenance, etc. Im my experience, chains last longer on SS or FG bikes than with derailleurs. I've probably put at least 7,000 kilometers on the chain on my FG winter commuter, which gets ridden in the rain a lot. It's still working.

SS chains are cheap, so it's not a major maintenance cost item when you do have to replace it. I've heard that cheap SS freewheels often break internally before the cog gets very worn, but they're cheap to replace, too.


----------



## waldo425 (Sep 22, 2008)

With a good chain and cog it should last through a nasty winter for sure. I had a cog that lasted from August until just recently. I had not taken care of the bike as much as I should have and had a chain that would stretch out like crazy. That plus high miles probably did it in. Cheap is good and all but you need to be careful with what you buy since cheap stuff can end up costing a lot more in the long run.


----------



## shibaman (May 2, 2008)

My original Shimano freewheel lasted 5600 mi. I am still using the original chain with 7400 mi. The only weak spot is the Shimano freewheel. Noisy!


----------



## Jim311 (Sep 18, 2009)

I noticed today that my freewheel had stopped clunking and making the noises it used to make when it was new. I like that the noise went away, but I wonder if that may mean it's going to blow up soon. It doesn't have more than a thousand miles on it I'd bet.


----------



## nate (Jun 20, 2004)

JCavilia said:


> Depends. Varies with riding conditions, maintenance, etc. Im my experience, chains last longer on SS or FG bikes than with derailleurs. I've probably put at least 7,000 kilometers on the chain on my FG winter commuter, which gets ridden in the rain a lot. It's still working.
> 
> SS chains are cheap, so it's not a major maintenance cost item when you do have to replace it. I've heard that cheap SS freewheels often break internally before the cog gets very worn, but they're cheap to replace, too.


The chain on my fixed gear always wears faster. I periodically need to tighten the chain tension, I assume because of chain wear. The rear hub is definitely bolted on tightly and not slipping. I am guessing it is because my chainline is a couple mm away from perfect and my chainring is slightly more oval than I would like, but I wonder if it may be because I need to replace the cog in back? I'm not really sure how many miles are on it, but after thinking about it I realize it probably has 6000 to 8000 miles. 

I just replaced my rear cogs on my geared bike recently and split miles almost evenly between the bikes. It made a huge difference and was long overdo on the geared bike.


----------



## JCavilia (Sep 12, 2005)

nate said:


> The chain on my fixed gear always wears faster. I periodically need to tighten the chain tension, I assume because of chain wear. The rear hub is definitely bolted on tightly and not slipping. I am guessing it is because my chainline is a couple mm away from perfect and my chainring is slightly more oval than I would like, but I wonder if it may be because I need to replace the cog in back? I'm not really sure how many miles are on it, but after thinking about it I realize it probably has 6000 to 8000 miles.
> 
> I just replaced my rear cogs on my geared bike recently and split miles almost evenly between the bikes. It made a huge difference and was long overdo on the geared bike.


You probably do need a new cog. On the bike I mentioned above, I noticed last week that the drivetrain was starting to feel a little rough, and when I checked it the chain was elongated enough to warrant replacement (about .75 %). When I put a new chain on, it ran roughly under high load, and on inspection the cog, which had about the same number of kilometers on it, also was warn enough to need replacing. Everything is smooth now. 

Cogs are more expensive than chains, but even replacing both together was under $40.

Your less-than-perfect chainline may be contributing to faster wear, but I wonder if you're also keeping chain tension too high. Experienced guys seem to set up fixies with a little chain slack to reduce drag and wear.


----------



## Richard (Feb 17, 2006)

I have about 3000 miles on my 16t DuraAce cog, with a KMC 710 stainless chain. Very smooth and quiet.

Just for giggles, I put on a new Izumi chain and it was noisy. Put the KMC back on and it was silence again. Visual inspection of the cog doesn't show appreciable wear but I reckon it and the chain have "mated." I'll go through the winter (what we have of it here) and replace the cog and chain in the spring.


----------



## dookie (Oct 1, 2007)

chain tension & riding conditions are everything.

10k miles here and still going. changed the chain once, probably due again. ring/cog fine. dry conditions, loose drivetrain.


----------

