Chainset for 7sp Drive

The spacing of the cogs is different with the 7 speed vs the 9 speed cassettes, your 7 speed shifter will not work. This is assuming I understood your question correctly.

All the chains are different. 7 speed chains are wider than 8 speed, and 8 speed is wider than 9 speed, and 9 speed is wider than 10 speed. See a pattern here 🙂 So no they are not interchangeable at all. If you wanted to go 8 or 9 speed you would literally need to replace everything. The crankset, cassette, and derraelleurs need to be able to match the chain and the shifters the number of gears. Even the rear hub would probably need to chainge. Basically get the 7 speed chain or buy a new bike if you want more speeds.

Quoted post said:

Originally posted by Hecubus
All the chains are different. 7 speed chains are wider than 8 speed, and 8 speed is wider than 9 speed, and 9 speed is wider than 10 speed. See a pattern here 🙂 So no they are not interchangeable at all. If you wanted to go 8 or 9 speed you would literally need to replace everything. The crankset, cassette, and derraelleurs need to be able to match the chain and the shifters the number of gears. Even the rear hub would probably need to chainge. Basically get the 7 speed chain or buy a new bike if you want more speeds.

Well,yeah they are different. That does not mean you have to change everything when changing speeds. A 9 speed chain works with 7 or 8 speed. Sram 8 speeds dwork with 7 and 6 also. You are just tossing alot of hooey.

Quoted post said:

Originally posted by sayerr
Are Shimano Chain rings chain specific? I have a 7 speed
drive on my mtn bike and need to replace all the worn cogs. It might be a good time to upgrade to a 9sp drive but I but don't want the expense/bother of changing my RH shifter so I thought I'd source parts that all work with a 7sp drive. I need a new freewheel, cartridge, chain (HG50), crankset (to replace an Exage 300) and Rear Derailleur cogs.
All the Chainsets on the web, if they mention speed at all, say that they're 9sp compatible. None of them mention 7sp but I'm guessing this is because nobody uses 7sp now.

Is there any reason why a 7sp wouldn't be effective on a (so called) 9sp Chainset?

The short answer is you can use an HG 9 speed crankset with your current setup. Get a sram 8 speed chain and make sure the replacement cassette is also HG.

Quoted post said:

Originally posted by boudreaux
Well,yeah they are different. That does not mean you have to change everything when changing speeds.

Sorry but yes he would. If he changed the cassette to 9 speed he would have to change the chain and shifters. You won't be able to run a 7 speed crankset with a 9 speed chain, at least not if he intends to shift, so the crank would need to change too. A 7 speed front derrailleur will be too wide to shift 9 speed chains most likely and I'm not sure the front shifters throw is the same on a 9 and 7 speed but my guess is not. The rear hub will most likely not accept a 8/9 speed cassette unless he's lucky and running an 8/9 speed hub with a spacer and a 7 speed cassette. But you're right, the rear derraelleur can probably handle 9 speed as the range is roughly the same. So yeah, he might be able to keep the rear derraelleur, but everything else would have to had been replaced by now so why bother, just get a new one too.
And yes, you can get some 8 speed chains to run on lower speed setups but a 9 speed will be extremely dificult. 9 speed chains will barely even work right on 8 speed drivetrains.

Quoted post said:

Originally posted by Hecubus
Sorry but yes he would. If he changed the cassette to 9 speed he would have to change the chain and shifters. You won't be able to run a 7 speed crankset with a 9 speed chain, at least not if he intends to shift, so the crank would need to change too. A 7 speed front derrailleur will be too wide to shift 9 speed chains most likely and I'm not sure the front shifters throw is the same on a 9 and 7 speed but my guess is not. The rear hub will most likely not accept a 8/9 speed cassette unless he's lucky and running an 8/9 speed hub with a spacer and a 7 speed cassette. But you're right, the rear derraelleur can probably handle 9 speed as the range is roughly the same. So yeah, he might be able to keep the rear derraelleur, but everything else would have to had been replaced by now so why bother, just get a new one too.
And yes, you can get some 8 speed chains to run on lower speed setups but a 9 speed will be extremely dificult. 9 speed chains will barely even work right on 8 speed drivetrains.

That was not his original question. This if far from your original answer. But if he want's to do 9 speed he may as well do the whole thing. He can however use the crank he was asking about, an 8 speed chain and an otherwise 7 speed setup.

It would be cheapest (and easiest) to keep your 7-spd set up as long as your shifters are working. Not sure where you are, but you can get 7-spd specific chains, cassettes, and new chain rings at www.nashbar.com (a US company). As long as the BB spindle holes on the crankset aren't rounded, you should be able to use your old crankset w/ new chain rings.

Otherwise, to go all the way, you would basically need a new rear wheel (hub width and spoke length would change). Pretty sure spacing is the same (135mm) for 7-spd vs. 8/9-spd hubs, so it should work in your frame. You'd also need new crankset, cassette, chain, shifters, and possibly brakes (this depends on whether you have separate brake levers or a shifter/brake lever combo). The new V-brake levers aren't compatible with cantilevers.

Of course by the time you spend all that money on upgrades, you may just want to get a spankin' new or new/used bike. Just my US$0.02.