Quote:
Originally Posted by spiderz17
I have not. I've read a lot of people extolling on the theory that smaller rims should be better, but I haven't seen any actual comparisons.
|
Here are some published road test observations.
Automobile Magazine, 2009 V6 Camaro:
"Steering feel is still under development - at the time of our drive, the 18-inch wheel and tire package offered much better feedback and feel than the 19-inch setup"
http://www.automobilemag.com/reviews...equipment.html
edmunds, Z4 35is:
"And with this lower-profile rubber, the Z4 35is should grip better and handle better than the 2009 Z4 35i with 18s (225/40R18 front, 255/35R18 rear), and all will be forgiven, right? Sorry, no.
Apart from the tires, the suspensions on these two cars are pretty much identical. Our 2011 Z4 35is comes standard with the M suspension, which specifies adaptive dampers (and driver-selectable Normal, Sport and Sport+ modes) and a 0.4-inch-lower ride height. Our 2009 Z4 tester had this setup as an option.
Yet the Z4 sDrive35is is much slower than the 2009 Z4 through the slalom. Its 66.7-mph performance — versus the 2009 Z4's 68.9 mph — is closer to what we'd expect from a front-wheel-drive family sedan than a rear-drive sports car.
Blame goes to those very short, very stiff sidewalls, which don't have enough compliance to stay glued over bumps and ripples. There's a small dip at the third cone in our slalom that sends the car skittering sideways and makes our test-driver late for the next cone. The more aggressive damper maps in Sport and Sport+ modes only make the car more nervous, something we also notice when picking up the pace on local back roads."
http://www.insideline.com/bmw/z4/201...full-test.html
There are other tests on the web indicating that lower-spec cars feel better over real-world roads. Eg. Seat Ibiza FR vs Cupra, CTS 2.8 vs 3.6, Mustang GT vs V6, Z4 23i vs 35i, E250 CDI vs E500 etc. While it's not always down to wheel sizes or aspect ratios (though those do affect the ride), a softer setup is sometimes preferred, and that's what a taller sidewall can help to acheive. It should be noted that some of these models have more power and heavier engines, so need stiffer setups to maintain body control.
BTW, in an old article of Evo Magazine, they answer a reader's technical comments about why F1 uses such tall sidewalls. While the sizes of the wheels are limited by the rules, the benefit of the sidewall is that the tires are doing some of the work of the suspension, which would otherwise deflect more were it not the very high spring rates they need to run in order to keep the cars from bottoming out under high downforce. Additionally, the extra squirm helps keep more rubber in contact with the road in bumpier corners, and it can help to increase the contact patch under high cornering loads. Which is also partially why dragsters run wrinkle-wall tires (not in corners obviously, but with added benefit of weight transfer).