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
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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.
Thanks, Lee! This was just the sort of information I was looking for to make an educated decision about the gears I’ll be running this year. This is exactly why I dig this web site!
Hey-you should get out here to the UK and check out the national races!
Once again, thanks, Lee.
I’d love to get out there. It’s a big world with lots of cool people and fun riding!
Kind of busy here for now …
I would analyze what gears/ratios you use and then search for a cassette with narrow ratios in this area. Before I set up my current bike I recognized that I always use 38/19 or 38/17. So my new bike has just 4 gears: 36t Chainring with 16/17/18/19t cogs give me all ratios I can use for 4X and dirtjump, close ratios and save some weight. Youth cassettes seem to be perfect, because they have very close ratios in the range used in 4X (I don’t know anybody using a 11 or 12t cog).
I, uh, apparently suck at math and entered the wrong number. What I wrote was insightful, humble, and so impactful it very well could have changed the world. Instead, I’m left with:
Bob found good combo. Go fast. Smash track.
Also, if you ever find yourself with the time and the money for a worth while trip to England, I’d be more than happy to show you the hot spots to ride, Lee!
Thanks for the input, Jonas! I’d never thought about youth cassettes. You’re right, I, like most people, don’t use the 11 or 12 cog-I just set my derailer to block those out.
A friend of mine just set up his bike similar to what Jonas described.
He used a single-speed Hadley hub (cassette style) and dissasembled a cheaper cassette to use the 5 or 6 cogs he wanted.
The result is a stronger zero-dish wheel, better chainline, less chain, less weight, and all the gears you really need.
Go with the close ratio set up. Also durability is more important than weight savings, so I run 105 rear cogs, they are cheap and last longer. Manage your chain line – inspect your front chain ring and rear cog often, and replace your chain often.
Remember 4x racing is about aggression, savage power, and leg speed. The fastest rider doesn’t always win the race, but the rider fastest to the first turn has the best chance of winning the race. Find the gear ratio that gets you to the first turn fastest, a friend and stop watches are useful for determining this.
“… aggression, savage power, and leg speed …”
Keith is an expert on these. I know first hand!
OK-the final testing has been done-the bike has been tested, refitted, then tested again. The final set up has me powering through the gates and tracks like a funny car and the shifts are super smooth!
Thank you, Lee, Jonas, and Keith for your input!
Saint shifter, 38 front ring, 12-25 rear cassette. As tested at the 4x track at Chicksands, UK.