In terms of performance, is there an optimum size of wheel?...
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In terms of performance, is there an optimum size of wheel?...
When it comes to wheels, many seem to think that bigger is better. 18s are better than 17s which in turn are preferred over 16s. 19s would be great, if only they'd fit!
I was just reading a review on the R32, and the author was wishing for a wheel 1" *less* in diameter.
So that begs the question, is there an optimum wheel size for our purposes, viewing the question solely from a performance standpoint?
I was just reading a review on the R32, and the author was wishing for a wheel 1" *less* in diameter.
So that begs the question, is there an optimum wheel size for our purposes, viewing the question solely from a performance standpoint?
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Interesting write up in C&D(?) this month on just this topic.
It's the issue with the Mercedes -vs- GTO (2 for the price of one) issue. They were mainly talking about increasing the rolling diameter, too, though.
Just increasing the rim, keeping the outer wheel diameter the same (plus one sizing) probably doesn't impact performance -- unless you're adding more unsprung weight (which of course, you are, by adding heavier rims).
Their analysis was (and I believe the physics holds) is that adding weight in the rims has twice the impact to acceleration, and moreso to braking than just adding sprung weight.
With that said, they though plus one sizing was the _most_ they'd recommend, it wouldn't hit performance too badly.
Just increasing the rim, keeping the outer wheel diameter the same (plus one sizing) probably doesn't impact performance -- unless you're adding more unsprung weight (which of course, you are, by adding heavier rims).
Their analysis was (and I believe the physics holds) is that adding weight in the rims has twice the impact to acceleration, and moreso to braking than just adding sprung weight.
With that said, they though plus one sizing was the _most_ they'd recommend, it wouldn't hit performance too badly.
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Don't forget the weight of the tire.
A much earlier post reminded us that the operative variable is the combined weight of wheel and tire. 18" wheels are heavier, but 18" tires are lighter.
I suspect that the difference between 18" and 17" is minimal, in both weight and in sidewall stiffness. You're going from a 45 profile to a 40 profile (e.g. 225/45-17 vs 225/40-18) with a Y or W rating. I recall the days when VR50 was considered extreme.
I suspect that the difference between 18" and 17" is minimal, in both weight and in sidewall stiffness. You're going from a 45 profile to a 40 profile (e.g. 225/45-17 vs 225/40-18) with a Y or W rating. I recall the days when VR50 was considered extreme.
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larger diameter rims aren't necessarily heavier....
...e.g. stock 17" alloys are ~21.5lbs each, but OZ Supperleggera 18" are ~17.6lbs each.
And keeping the same rolling diameter effectively means the tires will have a shorter sidewall, thus less tire flex and better handling.
And keeping the same rolling diameter effectively means the tires will have a shorter sidewall, thus less tire flex and better handling.
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Size doesn't matter - weight matters.........
and not just wheels but tires AND wheels combined. Forged wheels are lighter and stronger than cast wheels. The type of tires matter as well. If you car comparing the SAME wheel and tire combo in 17 vs. 18 then the 17 will always be lighter and hence perform better.
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Maybe they are, but I thought the article was well written,
some good lab / real world results -- I think they did testing at Michelin, and did some cool things like lap times with the same car but under / over inflated tires, also some hydroplaning / blowout handling tests. Quite interesting.
The biggest thing I learned is that the car will handle _much_ better with tires overinflated by 5 psi, than underinflated by 5 psi...
later
The biggest thing I learned is that the car will handle _much_ better with tires overinflated by 5 psi, than underinflated by 5 psi...
later