Quote:
Originally Posted by CapriRacer
You have to be really careful here. "Skinny" can mean different things.
If you start with a 185/65R15 and go to a 175/65R15 (which is your question), you are not only getting a smaller diameter, you are also getting a lower load carrying capacity, which has safety implications (that is, a more intense loading is directionally towards more frequent tire failures.)
PLUS, that is the wrong direction for RR. Tires don't like being more intensely loaded and one of the ways they exhibit that is in the amount energy they consume - ie, Rolling Resistance.
But "skinny" could also mean "narrower, but taller" - like going from 185/65R15 to 175/70R15. The problem here is that load carrying capacity plays more of a role in RR than width.
If you want to improve RR by changing tire size, get the largest tire that will fit under the fenders - without rubbing, of course. There is a couple of percentage points to be gained here.
Barry's Tire Tech |
You have stated several issues and now am lost and concern
Your terms quoted "skinny, tall, and large" just confuse and jade my perspective and not my understanding
Clearly going from 15 inch to a large rim 17 inch only reduce mpg and there is a thread already that is active to that accounts for that very experience