Is 1/2" leaf spring relocation worth the trouble?

DionR said

Nice! Your googlefu is much stronger than mine. :D

Years ago I read "The industry rule of thumb is that for every 1/2" change in rim width, the tire's section width will correspondingly change by approximately 2/10"(5mm)."

Based on that, his section width would be about 12.2". I assume the tread width doesn't change much though?

My benchmark for a tire that exceeds the expected specs is the RT660. A 295/30R18 in brand would be 12.1/10.8. So the section width of the 315 on that 10" tire wouldn't be really any larger, but the tread width would be almost an inch more, assuming tread width doesn't change when the tire is squeezed on a smaller rim.

Click to expand...

I don’t want to know how much of TireRacks bandwidth I use up! :rofl:

So with the section width it depends a lot on the tire geometry, obviously a tire with a short sidewall can’t vary as much from the rim width as a tire with a taller sidewall. Like when I went from 295/35/18’s on the back to 295/40/18’s the section width increased even though the wheels were the same exact 18x10’s.

The same goes for the tread width. If you squeeze a tire on a smaller rim it will bulge the tread, but you can get that back by running a lower tire air pressure. Of course that has limits too, and that will also be effected by the particular tires sidewall height etc.

So generally yeah, the tread width is less effected by the rim width than the section width, but the further you get from the measuring rim width the more the tread width will be effected.