Road and Track Tire Size Article

[BBausser]

Read a short article at the library in the current Road & Track, maybe Car & Driver about rim and tire sizes. They used a VW Golf and ran the tests with different size rims and tires. They used Goodyear Eagle GT's in all the tests and the tires were sized to match the rims anywhere from 19 X 9's to 15 X 6's. I was surprized by the results. The smallest rims and tires (15 x 6's, with 195/65's) were notably the quickest (0-60, 0-100, qtr mile), had a average 3 mpg advantage and had the highest lateral force. The only negative was in braking - a 3 foot disadvantage from 100 mph. They attributed it all to - weight, something all racers know about unsprung weight. The lateral force figures surprized me.

[Soterik]

Can you dig that back out and confirm the magazine and issue? Like to read that, and I no longer subscribe to either one (wayyy too much to read around here these days...).

tks Bill

rgds,
E

[BBausser]

I read it at the library. Current issue. Next time I visit I'll make a copy and post it here.

Bill

[Scott Clarke]

It was Car and Driver, not Road & Track.

[karlusmagnus]

see here
e.c.n.t.m.m.l.e.t.p.
(extra characters needed to make message long enough to post)

[naparsei]

and had the highest lateral force.

I read that differently. It looks like the lowest grip. Also, in the 15" and 16", the text claims there was much more understeer. The biggest takeaway is that you can too large in diameter (performance degrades from 18 to 19), and that there is likely an optimal size for your car. It would be interested if they held the width constant (sidewall impact vs. width impact).

[BBausser]

Yep, I read the lateral wrong, pretty noticeable from the smallest to the biggest, but the speed and mileage figures are interesting.