Dumb Question, why 6" rims instead of 5" rims?

[paulkish]

Dumb Question, why 6" rims instead of 5" rims?

Is it because forced tires on racers are 6"?

Would 5" not work as well?
Couldn't 5" cheap slicks be treated to work?

I see $40 tire and rim on the net.

 

[Colt sr]

Spring rate of tire and clearance of chassis are the first things that come to mind

 

[sundog]

Less sidewall flex so you can run less air pressure.

 

[95 shaw]

In the quest for roll speed, Chassis were built around 6 inch diameter rims with widths greater than the tire tread width.
Both effectively shorten, and stiffen the tire sidewall for less rolling resistance.

Racers aren't "forced" to do anything. However, some things are necessary to be competitive with the chassis and classes available.