View Single Post
Old 06-10-2008, 02:16 PM   #107 (permalink)
Master EcoModder
tasdrouille's Avatar
Join Date: Jan 2008
Location: Mirabel, QC
Posts: 1,672

The Guzzler - '08 Hyundai Elantra GL
90 day: 33.12 mpg (US)

Got Soul? - '11 Kia Soul 2U
Thanks: 35
Thanked 86 Times in 57 Posts
RR is mostly about hysteresis. Reduce hysteresis and you reduce RR. Since roughly 80% of the hysteresis in tires happens in the sidewalls, make the sidewalls stiffer and RR will go down. The easiest way to do so is to increase the pressure. Btw, if you're adding material to make the sidewalls stiffer (same material, just ticker sidewalls), that won't work nearly a well as added pressure. Even though it'll flex less, more material will be flexing so overall hysteresis will pretty much stay unchanged.

Re tread width. It's not about skinny or wide, it's about finding the right contact patch size. Long contact patches from skinny tires increase RR due to increased hysteresis. Make the tread wider and RR goes down, up to a point where RR goes up again.

You can validate that in the graph posted earlier.
__________________ - Quand chaque goutte compte...
  Reply With Quote