Subject: Re: Crankset vs Cassette Posted by: Christopher Krenz on August 09, 2006 at 15:35:56: In Reply to: Re: Crankset vs Cassette posted by Al on August 08, 2006 at 07:07:44:

Message: >>>>I own a 2001 Trek 4500 mountain bike. I have been making minor upgrades to better my ride, and just for the fun of it. I'm in the process of making a major change with my crankset. Most cranksets indicate they work with 9 speed cassettes. I have an 8 speed cassette and am not planning on making the upgrade to a 9 speed for a while. Will the 8 speed cassette cause problems with a new crankset? >>>You should experience NO PROBLEMS using a crankset with 9-speed chainrings with your 8-speed drivetrain. >> >>Thanks. >>Why then is this mentioned with so many cranksets? >>-Chris >MY OBSERVATION, and others may choose to disagree, the significant difference is in the chainrings ... >An 8-speed chainring has a slightly raised band on its inside face ... >Generally, a 9-speed chainring is ramped-and-pinned -- the ramps-and-pins facilitate shifting the chain from a smaller chainring onto the larger one next to it. >And, a 10-speed chainring has thicker ramps-and-pins than a 9-speed chainring because the chain is narrower, but the plane of the respective chainring's teeth appears to remain a constant to one another. >You CAN use 8-speed chainrings with a 9-speed chain + EITHER a 9-speed Shimano (okay) OR Campagnolo (better) shifter ... but, the shifting will be slightly better if the chainring matches the chain. >The shifting might get too dodgy if you try to use an 8-speed chainring with a 10-speed chain, but maybe not. You should be able to use a 9-speed chainring with a 10-speed drivetrani, but the shiftig may be fractionally slower. >You should be able to use EITHER a 9-speed OR a 10-speed ring with an 8-speed drivetrain; and similarly, a 10-speed chainring with a 9-speed drivetrain. >MY OBSERVATION is that the chain should match the front derailleur (or, vice-versa) when using a Shimano drivetrain for efficient shifting ... and, the chain MUST match the front derailleur with a Shimano triple. There ARE some exceptions ... > Another question I have is...what is the importance of the crank length? I've seen 170mm to 175mm. What's the difference? Thanks again, CK