Subject: Re: Crankset vs Cassette Posted by: Al on August 10, 2006 at 04:41:18: In Reply to: Re: Crankset vs Cassette posted by Christopher Krenz on August 09, 2006 at 15:27:41:

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 ... >> >Thanks for all your help. >When I'm looking at new cranksets for cross-county riding, what are the most important features I should be looking for? What does ISIS mean in the description of a crankset? Do I need three chain rings or will two be sufficient? I usually only use one anyway. >Thanks again, CK ISIS is a type of "interface" between the BB spindle & the crankarms -- it has 10 robust flutes/splines. The ISIS design was a license-free (i.e., no royalties) response to the Shimano Octalink (8 splines) BB interface. The FIRST "batch" of ISIS bottom brackets were iffy because many did not have bearings adequate to handle the stress; hopefully, all of the BAD bottom brackets have been taken out of the retail stream ... The Octalink was Shimano's alternate to the square taper which was first introduced, AFAIK, by Campagnolo way-back-when (in the 60s ... maybe, in the late 50s!?!). Both Octalink & ISIS have been universally superseded by bottom bracket systems where the bearings are mounted OUTBOARD of the bottom bracket shell. There is ONE ISIS bottom bracket which has outboard bearings ... Campagnolo's 2007 cranks will also use outboard bearings. The advantage of outboard bearings for "normal" people is probably non-existent OTHER THAN for bragging rights. ONLY YOU know what gearing you need ... if you only want to run with two chainrings, then simply remove the granny. There were SOME 104BCD (the MTB crank standard) cranks which only have two chainrings (and, are NOT drilled to accept a granny). If the price was the same, then I would rather get a triple and then simply remove the granny. So, I wouldn't beat the bushes looking for a 104BCD double. A double IS easier to set up & maintain than a triple.