New chain. Do I need new Sprockets too?

Hey -

I just replaced my worn DID 520v6 o-ring chain with a new 520V o-ring chain. The front and rear sprockets look fine. Do I have to replace them too?


If they have had much use at all replace them, because the chain like fits with the sprockets as they wear and any other chain used with those sprockets will have a very short life.

It is very unusual for an o-ring chain to wear to the point of replacement without causing a lot of wear on the sprockets. We are talking easy to see wear.

What prompted you to decide that the chain was worn and needed replacement?

Out here in SoCal a good quality o-ring chain like that will last a very long time on a XR250. Like over five years, maybe more.

Normally, chains and sprockets should be changed at the same time. To not do so may cause accelerated wear on both the new chain and the old sprockets. If your old chain had stretched enough to need changing, you can bet the sprockets are worn, as well.

The old chain was missing a bunch of the o-rings (rubber bushings) and was pretty stiff.

my last name is beeman :thumbsup:

my last name is beeman :thumbsup:


deeman & beeman sound alike :thumbsup:

You are not making any sense.

not if they are stilll fairly new and in good conditon

You should replace them if they are cupped or noticeably worn.

The old chain was missing a bunch of the o-rings (rubber bushings) and was pretty stiff.

OK that's a good reason.

Like others have said, if there is any noticable wear to the shape of the teeth then replace them. The front usually goes first so concentrate on it.

How did the o-rings get damaged? Did you use a wire brush to clean the chain? Cleaning o-ring chains is an easy way to damage them. With just some chain wax or even jsut WD-40 that chain should last for years.

Replace them, you will probably have to soon anyways, no use in putting added wear on your new chain with old sprockets.

yah the two items are made to waer together and are designed that way

As already mentioned it is good to change them together. Also, WD-40 is bad for oring chains, it causes the orings to swell. It is best to use a lube that is designed for o/x ring chains. O-rings don't like certain petroleum products. It is best to lube the chain while it is warm, the lube penetrates better when the orings are warm. After I wash my bike I ride it around the block once or twice to get the water out of everything and I lube the chain as soon as I pull into the garage. At the track I lube the chain as soon as I come off the track so as to get it ready for the next moto.

I've always changed them as a set - chain and sprockets (both on and off road bikes). If the sprockets are really cherry - no wear or deformation at all, then I'd consider leaving them be.


Also, WD-40 is bad for oring chains, it causes the orings to swell.

I agree with that. WD40 is more solvent than lube, and some o-rings are not very solvent resistant.

As for replacing chain and sprockets as a set, I don't agree. As your chain elongates from wear, the distance between rollers gets longer, while the distance between the "valleys" of the sprocket teeth stay the same. The elongated chain will cause the tips of the teeth to curl over. This is bad. Sprocket tooth cupping, on the other hand, is normal wear and will not destroy your new chain as long as you still have a roller-to-tooth contact patch that is close to a new sprocket.

However, if you were to combine a new sprocket with an elongated chain, that new sprocket will get killed very fast.


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