[QUOTE=mans;276425]
Quote:
Originally Posted by Ryland
if there was a middle digit it would be like 125/150/R15 cuz the sidewalls are so tall while the width is so small!
see again here up close: Firestone F560 - 125R15 |
Remember... math is your friend.
125 tires have a 5" section width. 23 -15 is 8, so the section height is 4. Therefore the profile is .80.
http://www.wbdg.org/ccb/GREEN/REPORT...resistance.pdf
http://www.energy.ca.gov/2006publica...0-2006-001.PDF
Unfortunately the 560 is not listed in either of these, but the 560 is similar to the 680, and is probably about the same in Crr: .010. As you can see from the TRB report, most tires are pretty close to .010. The Bridgestone 381 is the only real standout.
Depending upon what you have done about aero on your car and how fast you drive, you might find that a a narrow tire has enough less aero drag to make up for average rolling resistance.
There is always tread shaving too. One characteristic of most Low rr tires is a thinner tread.