How to choose a compatible set of chain, cassette and chainring?

Question

I would like to change the chain, cassette, and the chainring of my bike. The cassette has 7 speed and chainring has 3. Is any combination of 7 speed cassette and 3 speed chainring built by any manufacture compatible? How should I choose the proper chain? Does any kind of chain from any manufacture work?

Answer 1

Bicycle chains are standardized. In general, cassettes, chains and chainrings are compatible with each other across manufacturers.

You just have to make sure you select a chain and chainrings that are compatible with the number of sprockets in the cassette. The number of rings on the crank does not matter.

(The difference is driven by the need for progressively closer spacing of the sprockets in the cassette as the number of sprockets increases. Chains for more speeds have to be narrower, which also affects chainring spacing and design.)

6, 7 and 8 speed systems all use the same chain width. Any manufacturers 6/7/8 speed chain will work for you. Similarly, any chainrings that fit your crank spider, and are designed for 6/7/8 speed systems will work.

SRAM and Shimano use the same free-hub body 'HyperGlide' standard (introduced by Shimano) so their cassettes are interchangeable. Other manufacturers such as SunRace use this standard too. Just check that cassettes are specified as Shimano / SRAM compatible.

A couple of notes.

• A cassette is technically a stack of sprockets that fits on a free-hub style wheel hub, where the freewheel mechanism is built into the hub. There is a older standard known as a free-wheel where the freewheel mechanism and sprockets come as one piece. If you have an older or inexpensive bike you should check which you have.

• If you replace the cassette you must replace the chain, as a worn chain will very quickly wear out cassette sprockets. Chainrings wear slowest. It's worth inspecting all three as one or two may not need replacing.

• If you are thinking of larger chainrings or a cassette with a larger largest sprocket, you need to check if your rear derailleur can handle the increased difference between smallest and largest sprockets.

Answer 2

You need a 7 speed chain, cassette, and chainring. You can mix manufacturer but most people just pick one.

With cassette and chainrings you will have a maximum hi to lo range based on the derailleur. If you stay close to what you have now you should be good. Check the chainring for wear. You may not have worn them all out.

If this is a dup sorry. I will delete.

Answer 3

Chains used to be pretty standard up to 8 speeds. So a 6/7/8 speed chain will work. It's a 3/32" wide derailleur chain. You don't need a 7 speed chain as a 6 speed or 8 speed chain will work equally well. However, a 9-speed chain would work poorly.

Cassette: a 7-speed cassette is a requirement (if you have a cassette), since 8-speed cassettes are wider and wouldn't work with your derailleur anyway perfectly, since there's a minor difference in click spacing between 7 and 8 speeds (and besides, even if you could tolerate that difference, 1 speed would be inaccessible with a 8 speed cassette).

However, it may not be a cassette. It may be a freewheel. Be sure to check before buying. Cassettes can be recognized easily by the teeth that the cassette remover will go into, in the lockring. A cassette remover is a must-have tool in any toolkit as it removes centerlock disc brake rotors too, so be sure to buy one.

Chainrings also are pretty standard, but they are getting narrower slowly. A 10-speed chainring might work, very likely a 9-speed chainring works perfectly, a 6/7/8 speed chainring works perfectly. It isn't so strict what type of chainring you have, since in the front the spacing isn't equal to spacing in the rear. Sheldon says:

Going the other direction, using wider chains with chainrings intended for narrower chains is not generally a major problem if there's only a one- or two- generation difference. The only problem you might run into is that the chain will be more liable to rub on the inside of the bigger chainrings in the small/small crossover gears, gears you shouldn't be using in any case.

For chainrings, check the bolt circle (4-bolt 104mm, 5-bolt 110mm, 5-bolt 130mm) and choose accordingly. If you have a triple, check the bolt circle of the smallest "granny" ring too. In the worst case, the crank may have permanent chainrings that you can't change without changing the whole crank (and if this is the case, it's almost surely a square taper crank which might require changing the bottom bracket too to change the crank, since bottom bracket lengths vary and there are two incompatible tapers, ISO and JIS).

In the upvoted answer:

If you replace the cassette you must replace the chain, as a worn chain will very quickly wear out cassette sprockets. Chainrings wear slowest. It's worth inspecting all three as one or two may not need replacing.

...is false. A new chain might or might not work on a worn cassette, but a new cassette always works on a worn chain. Yes, it's true it wears slightly faster, but then that's life. If you change your chain at the 0.5% mark, you might have the possibility of wearing many chains per cassette, even if you sometimes use a new cassette with a worn chain.

However, if you replace the chainrings, chances are you must replace the chain too. An old chain might not work with a new chainring.