Gearing for 4x/DS racing

Hey, Lee.
First-Thank you and thank Brian for writing that book! It’s really made me a much better rider and racer.

Second: I’m getting ready for the 2007 4X racing season, and I’m thinking of changing my rear cassette from a MTB (11-32) to the road cassette (11-25), but I’m not sure why I’d do this, other than your book suggests this. I just want to make a good decision before I throw down the cash!

Thank you, Lee!
Bob

Hey Bob,

I have indeed recommended a road cassette in the book and on this site, but I’ve rethought my position.

A 34t ring with a 12-25 Ultegra cassette yields the same useful gears as a 40t ring with an 11-32 XTR cassette. Jon Watt here in Colorado runs the latter, and that’s what got me thinking. Each setup seems to have its advantages:

34t x 12-25

– More ground clearance. Great for urban/skate park.

– Closer ratios. Easier to pull the next gear.

– Lighter. ~10% less material.

Who it’s for: The clearance is nice for urban/skate. Closer ratios help riders who aren’t super powerful. If you don’t break chains, this will work fine. I currently run this setup on my P3 and SX.

40t x 11-32

– Less chain tension. The bigger ring reduces chain tension by about 15 percent. This is a real advantage for strong 4X racers. I’ve snapped chains out of the gate, and it sucks!

– Fewer shifts. You access the same range with one fewer shift.

– A little less chain friction. Less tension plus less bend to get around the bigger gears.

Who it’s for: Strong racers. The reduced chain tension is a real advantage. The wider shifts are fine if you have the power.

The “useful” gears are based on my experience. Weaker riders will need easier gears; stronger riders will want taller gears.

Lee Likes Bikes — Nerding out since ’03.