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Comment by LeifCarrotson | Hacker News Reader

Vehicle weight is not directly proportional to axle count - a 9 axle semi with trailer can weigh 80,000 lbs or 9000 lbs/axle, a 2-axle car weighs 3500 or 1750 lbs/axle. Alternatively, multiplying axle count by 4.5 increases vehicle weight by 25x - so the two can both be true at the same time, the power just changes whether you use vehicle weight or axle load.

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What effect does tire width have? Very narrow (<165mm) tires vs dual tires of trucks for example. Smaller area of friction versus lower pressure

>What effect does tire width have?

probably quite an effect, but reducing damage via width will also decrease vehicle efficiency and increase rolling resistance, so the gains at the road may be lost in an overall loss of efficiency at the vehicle, not to mention manufacturing and materials cost, when finagling the tire-width variable.

I don't have any numbers, though.

> will also decrease vehicle efficiency and increase rolling resistance

Not necessarily; one could formulate the tread rubber for such wider tires so they're less grippy per square cm of tread contact-surface, and so exactly as grippy as before per fully-loaded tire. Basically making every change in the opposite direction from what dragster tires do (other than the width.)

That's for peak power. Efficiency is lost in the deformation bending and returning of the walls of each tire as it rolls. i.e. A really highly loaded tire needs to be really well pressurized to prevent overheating and failure due to the losses.

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