Calculating Wheel Size

[Andrew]

Thanks for the words of wisdom, Paul.

I have been an advocate that smaller is better in tires for the reasons you have listed (primarily efficiency). The question is not how large a tire can you choose but how small.

Limiting factors on minimum tire size include ground clearance and obstacle handling (bumps, etc). An additional factor in "smalling down" the tires is weight. If you use the minimum GR that you can get away with, you will have fewer gears.

Therefore, smaller, thinner tires give you less weight in the tire, less weight in the gears in the gear boxes, and less weight in the walls, spacers, and other gear box parts.

The issue of ground clearance can be solved with wheel diameter. But, it can also be solved by using a suspension. I'm surprised at how few teams have looked into suspensions. Although the suspension does add weight back into the equation, this can be traded off against the weight deleted in slimming down the gear boxes.

If you take 10 lbs out of your weight by going to a very small wheel and add back in 2 lbs in suspension parts, you are a net 8 lbs lighter for accomplishing the same task.