In article , Ed Huntress says...

But you still have the same load, distributed now across the area of three
bearings instead of four. Specific friction (friction per square mm of
bearing area) goes up...but how much? How linear is the load/friction curve
for mild steel against acrylic, or whatever it is?

Consider the limiting endpoints where you have some *huge* number
of wheels, as many as would fit inside the bounding box. You
just know that car's gonna be a dog.

I think the simple answer is easy - you just run a car and time it.
Then take one wheel off and run it again. Just have the weight
rigged so it will run ok with three. If it really makes a difference
then it should be easily visible in the times.

Jim


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