Ok gang, help educate me. This is the first time I have owned a good bike long enough to overhaul the drivetrain. I currently have a stock drivetrain on a 2005 Fuji Sagres: 52-42-30 cranks that need replacing, 8-speed cassette, which I just replaced last week along with the chain, Acera RD and whatever FD came with it.

I am interested in swapping out the cranks for an inexpensive compact double, as I am also converting this hybrid to a cross/commuter with drops and all. I also do not wish to upgrade to a 9 speed system as I have already spent money on 8 speed components.

That being said, I have found a compact double that is a 9 speed, as most seem to be. Assuming FD change to match this crankset, will I need to change anything else in the drivetrain to be sure of flawless operation? The only thing I can possibly see is the chain, to match the 9 speed crank. Is it important that the crank is rated at 9 speed with my 8 speed cassette, or is this crank '9 speed compatible'?

Thanks in advance.