Chain rings and Cassettes

How often do these need to replaced?

I’ve got a POS bike that came with sora components. I’m thinking of changing the gearing and it sounds like I can build my own cassette by buying different individual gears and assembling them on the original cassette body? (I’ve been looking the at park tools web site). Is this correct? Is this how everyone does it, or do people commonly buy entire new cassettes?

right, every three-four thousand miles or so. but remember, the cassette and chain wear together, so if you wait to replace the chain until it absolutely needs it, the cassette will need to be replaced as well. better to replace a chain every 2000 miles or so, and spend twenty bucks, than 20 bucks plus 150 for a cassette every time.

tommy

Tommy, if you’re paying $150 for a cassette, I’d suggest you find a new LBS. You should be able to find an Ultegra cassette for $40-55. Regardless, I still agree with your point.

better to replace a chain every 2000 miles or so, and spend twenty bucks, than 20 bucks plus 150 for a cassette every time.

I agree. Skip using those chain wear indicators. Just replace the chain every couple thousand miles and the whole drivetrain will last much longer and work much smoother. It’s like the oil change in your car. Sure, you can push your oil changes past 3K, but it’s great cheap insurance that ensures your engine will last a long time. I don’t waste the money on expensive chains either. Just a good middle of the road chain will work fine.

I’ve got a POS bike that came with sora components. I’m thinking of changing the gearing and it sounds like I can build my own cassette by buying different individual gears and assembling them on the original cassette body? (I’ve been looking the at park tools web site). Is this correct? Is this how everyone does it, or do people commonly buy entire new cassettes?
It’s actually not common to do it that way. Almost everyone buys complete cassettes. If you are going to do it piece-meal, make sure you know what you’re doing. There are compatibility and shifting issues to be dealt with.