Bicycle Mechanics - quick crankset question

Can I use an 8 speed crankset for my 7 speed bike? I know can't use 9 speed because 9 speed chains are narrower, so the rings have to be different.

I just ordered this cranket, except it is silver. I sure hope it works it is 8 speed.

I believe it will work (could be wrong) but here is my reasoning... I have a six speed, that I know I could put 7 speed on. And I know that my 6 speed crank would work. I also know that my derailleur will work 6-7 speed. and that newer derailleurs work from 7-9. so, if the crank is specifically made for eight speed, it will work for 7 because there is as I understand it, no change in chain size from 7 to 8, as there is no change from 6-7.

now if I haven't totally confused you ;)

Thanks Vegas, I think it will work too. Can't wait till it gets here!

It's purty. If it doesn't work, you can always hang it up to decorate your room. :)

Originally posted by JonR
It's purty. If it doesn't work, you can always hang it up to decorate your room. :)


JonR, I was fixing up my little sisters bike the other day, and I had to swap out the chainring on her bike with a chainring off another single-speed kids bike we had sitting around because hers was bent. So I had this bent chainring so what did I do with it? I hung it on my coolio bike stand, plus I had a few chain links.

It will work Matt, 7 and 8 speed chains are the same , both use a 7.1 mm wide chain, 9 speed are 6.5 mm wide . :)

Thanks Buddy! For 25 bucks I couldn't pass it up, I needed some new rings anyway.

I put some Tru-Vativ's on my old Mongoose early last year Fubar. They are pretty good cranks. I think you'll like 'em.

Originally posted by Dirtgrinder
I put some Tru-Vativ's on my old Mongoose early last year Fubar. They are pretty good cranks. I think you'll like 'em.

Great!! I'm trying to get some new parts for my wierd BB too. Then my bike will be set, it will be completely rebuilt except for the derailieurs, which are fine.

Front ders/shifters seem a lot less finicky about cranksets than rears are. I am running a crank off of an old 12 speed that is working fine with new 9 sp STI shifters and der.

I can't wait to get it man!!! According to Truvativ that crankset is super stiff. It usually retails for 60 bucks, Pricepoint had it for 25.

No problems using my 9-spd XT crank with a 7-speed rear. The rear seems to take a 9-spd chain just fine.

I refuse to upgrade to any more speeds than are practical. The stumpjumper is now a singlespeed for that matter, so I guess I'm moving in reverse!