rear cassette worn

[Jen]

I bought a used bike. I noticed that the rear cassette teeth look worn. Kinda like shiney half moons. Does that mean it is time to replace the rear cassette, maybe the front also? Noticed that the bike doesn't go into gear easily. Thought at first that it just needed an adjustment.

[emily_in_nc]

Yes, you need a new cassette! My husband just replaced the one on my new (used) mountain bike, but it does require special tools.

I would recommend taking your new (used) bike to a good LBS for a look-over and tuneup. They can replace anything needed and get it shifting well for you. Mine needed new shifter and brake cables, a new chain, and new pulleys for the rear derailleur as well as a new wheelset as the hubs were shot in the rear wheel. Replacing all this was a bit pricy, but I still got a good deal on the bike compared to buying brand new.

A good LBS can also fit you to the bike and determine if any fit-related changes are needed, such as a different length stem. You might need a different saddle to make your anatomy happy too, but you probably won't know about that until you ride the bike some.

If you don't have one already, make sure to purchase a helmet while you are at the bike shop!

Enjoy your new bike.

Emily

[DebW]

I bought a used bike. I noticed that the rear cassette teeth look worn. Kinda like shiney half moons. Does that mean it is time to replace the rear cassette, maybe the front also? Noticed that the bike doesn't go into gear easily. Thought at first that it just needed an adjustment.

You probably do need a new cassette and chain. The real test is if the chain skips over a tooth while riding and hammering hard, but since you got this used and don't know it's history, might as well start fresh. The front chainrings probably do not need replacement, as they wear far far longer than a cassette and chain, but using a chain after it's stretch badly can wear them. Compare their tooth shape to that of a new bike, and see if the chain still fits the ring snugly all around. You should also replace the derailleur cables and grease them up good. After all that is done, then it's time to adjust the derailleurs. Since this bike was probably not maintained well by it's previous owner, you should really get someone to check it completely for grease in the bearings (hubs, bottom bracket, headset), brake adjustment, etc.

[Jen]

The bike was very well maintained, probably more than most but she rode alot of miles on it. The back cassette is probalby worn and it may need adjusting on the derailleur. It goes into gear but doesn't sound smooth. The chain has a gold colored link in it. What is that for? I had a much better bike, and extra small carbon composite but it never felt llike it fit me. This bike is a small, same make as the bike before and is much smaller, much better fit. How can this be? The guy at the LBS said that tiagra was a very good derailleur but from my experience it is a tad slow. An Ultegra doesn't cost all that much.

[DeniseGoldberg]

Deb is right - it's more than likely that you need a new cassette and chain. I've found that if the chain is replaced much earlier than recommended that you can get away with just replacing the chain (once maybe, so replace the cassette every other time you replace the chain). But if the chain is really stretched, then you are going to need to replace the cassette too.

--- Denise

[Jen]

Thanks everyone. I always like knowing what to expect before I take my bike in. Doesn't sound too expensive. A little at at time. The forum is so helpful.