Bicycle Mechanics - 9 speed cranks on 8 speed drivetrain

My wife has a 2004 Gary Fisher Marlin. She would like to change the crank lenght to a 170mm from the current 175mm lenght.

I have a new '04 RACEFACE DIABOLUS X-TYPE MOUNTAIN BIKE DH CRANKSET that is a 170mm in lenght. I am not using it and would like to put it on her bike to save some money.

My question is..... Would this crank set work on her 8 speed drivetrain? The front and rear der. are both Shimano deore.

Thanks :D ;)

The alignment may be slightly off...that's what I remember from the last time I attempted it. For the most part it'll work, but you may need a wider cage derailleur so the chain doesn't rub -- unless you don't mind rubbing.

Worked fine for me, and when I went to 9 spd in the back, it was ready.

Since you have it, myswell try it...

I recently needed to purchase an 8 speed crankset, which I found hard to find. I had read "The 9-speed chainring release teeth and pick-up teeth are re-profiled for the narrower chains. Therefore, you cannot use an 8-speed chain, and the pick-up teeth will make noise against the chain during minor cross chaining. " at http://www.worldcycleboise.com/techtips.htm and similar things at other places that suggested not to mix 8 speed and 9 speed parts, although my LBS said it would work fine to use 9 speed chainrings on an 8 speed drivetrain.

AFAIK, SHeldon says it should work. Worst case scenario is that you would get some minor noise. If that is so, there is one easy solution:

- Use a 9-speed chain.

The 9-speed chain will work equally well with an 8-speed drivetrain, and for the price differencial, you will be able to buy a lot of 9-speed chains before you pay for a mew 8-speed crankset.

Thanks for all the help. :D