View Single Post
Old 04-27-2008, 11:09 PM   #17 (permalink)
LostCause
Liberti
 
LostCause's Avatar
 
Join Date: Feb 2008
Location: California
Posts: 504

Thunderbird - '96 Ford Thunderbird
90 day: 27.75 mpg (US)
Thanks: 0
Thanked 7 Times in 7 Posts
Quote:
Originally Posted by CorollaMaster View Post
LostCause - I think the sidewall flex would be another reason to pick a larger diameter rim and slimmer tires. There is less sidewall to flex, and as a result probably a lower contact surface as well. The main benefit though is the displacement of all the weight to the outside of the wheel.

I also wanted to respond to your comment about the contact patch. The contact patch is relevant because its the amount of area that the car is putting energy into to make it move...
Larger diameter rim = more weight. A slimmer tire also doesn't necessarily mean less sidewall flex, as it could just be concentrated into a smaller area.

The contact patch is irrelevant in an ideal world. If nothing ever deformed/slipped, it wouldn't make a difference if you were pushing a car with a tennis shoe or the head of a pin. Therefore, in the real world, it is not the contact patch that is the issue, it is something else. The contact patch just manifests an issue concentrated somewhere else.

I'm not saying to disregard the contact patch, but to understand that rolling resistance does not lie solely in its geometric shape.

- LostCause
  Reply With Quote