How much does wheel weight affect performance?

[Will BRZ]

I think people run heavier wheels because they tend to be the most cost effective and “best looking” which is fine to a certain extent. There are wheels on the market that weigh up to 27 pounds and people still buy them. On the other hand, you can get super light wheels that will be more expensive, obviously. I never understood buying 25lbs+ 9.5 wide on 255s with stock power, but that’s just me.

There are a few wheels that hit the sweet spot in terms of price, weight, and looks. Then it comes to manufacturing process, BBK clearance, wheel/tire sizing, suspension type etc. Do your research and buy whatever you like and what fits your needs.

[why?]

Originally Posted by churchx

Hmm. I find few reasons to justify a bit bigger sized wheels even for daily driving. - Steering feel (better performance tire choice & brake clearance probably matters less for DD).
On smaller wheels higher sidewall profile with a bit more slop will still provide good grip, one can still go fast on smaller tires and tires will be cheaper and ride a bit more comfortable/compliant.. but feel, that sharpness of turn-in will be a bit compromised. I love handling and feel of it in twins, thus among my wishes/preferences is to keep a bit more "feel"/enjoyment. This is driver car, for driver enjoyment. I want to retain that enjoyment.
Yes, 18" might be even more in "feel" direction, but imho 17" is good all-rounder compromise, good enough clearance for multiple BBKs, better performance tire selection, while more expensive and less compliant then 16", cheaper & more compliant then 18".
With one exception (and again with that "feel" involved) - winter tires/use. Winter tires will be sloppy no matter what due softer rubber compound, winter tires on 17" on 18" still won't net better handling feel, so this lacking "feel" won't justify some cons of bigger wheels as result pros of smaller wheels & tires going ahead, eg. on worse roads in winter extra compliance & rim protection of higher profile may matter more, cheaper tire cost always is good, and on bigger wheels -winter-tire- selection is worse, with harder to find narrower tires for wheel size, for optimum grip on ice & snow.
So as result i use light 17" set for summer, and have 16" set for winter use.

The feel you are speaking about is mostly due to the stiffness of the sidewall and the weight of the wheels and tires. Softer compounds grip better, funny how you think softer compounds on winter tires are worse, yet softer compounds on summer tires are better. It is about the actual compound, not how soft it is.

[Spuds]

Originally Posted by why?

The feel you are speaking about is mostly due to the stiffness of the sidewall and the weight of the wheels and tires. Softer compounds grip better, funny how you think softer compounds on winter tires are worse, yet softer compounds on summer tires are better. It is about the actual compound, not how soft it is.

I think the point is that the tread pattern on winter tires makes for squishy tread blocks, and that along with soft compound allows the tread to deform too much under load. Excellent for driving on ice and snow, not so great for dry pavement.

[churchx]

Well, i guess combination of all real winter tire construction bits. Soft compound, many thread mini sipes and mini thread blocks that move around alot, soft sidewalls that flex a lot, later two, moving around thread blocks & sidewall flex generating lot of heat, overheating soft compound (which i guess is not exactly "low threadwear track slick" soft, but soft because of different chemistry (recall mentioned used more silica in compound in PR materials), that works bad grip wise when overheated.

Well .. whatever the reasons, even on bigger wheels and with low profile, even with higher pressure, all winter tires feel like crap in summer. There might be some slightly better, eg. some "european winter tires" or all-season tires (but they still have softer compound, still more thread sipes, still softer then average summer tires, even if not as much as bad as "nordic/scandinavian" winter tires), but not without sacrifices in main functions of ice/snow grip.

So while i want that steering feel, i'm giving up on that for winter tires as unavoidable evil .. but for reasons described in previous post of mine want that feel on 17" wheels/tires where i don't have to do sacrifices, in summer. Even if for DD-only (though i also track, but relatively little). Side bonus - for most, as R17 wheels are stock on twins, they got set of it for free as OE.

Yes, real sport recipe is "use smallest wheels that clear brakes on car" for the very best performance and have used tire sizes available (if not regulated by class / race or sponsorship rules), but i use my car for self-driving-enjoyment-fun. And while not willing to move even further up in sizes, imho 17" wheels/tires hit "sweet spot" for summer use, more so then 16".

[Yoniyama]

I find it hard to believe anyone who has driven the Toybaru with a super-light 16-inch wheel (eg Vols Racing TE37) and 205/55-16 tyre, for any application (street, track, or rally), can still go back to an over-weight 18-inch wheel/tyre combo.

The change in unsprung weight, at more than 15lb per wheel, makes a vast difference in handling and ride quality.

As for the looks, I doubt if any non-automotive oriented chick could tell the difference.

[churchx]

My current summer wheel set is of forged 17x7.5 wheels of 6.2kg each. that's 1/3rd less weight then OE wheels of 20.1lbs. I guess, good forged 16" would be another half kg less.
From my experience for DD or track, while there was difference i could felt (not so much in acceleration, but more how suspension worked/felt), it was far from "vast" difference. Let's say .. different people have different sensitivity "butt dynos", and also sometimes there comes positive affirmation placebo bias of expensive purchases.
So yes, it's nice bit to have lightest wheels if one can afford it, but it's not THAT important as eg. right tire choice or right suspension setup/alignment. Or if OEM wheels are way more on heavy side like for some other cars (20.1lbs of twins OE cast Enkei wheels imho is below average OE wheel weight). In my opinion hunt for lightest wheel setup shouldn't be prioritized that high, rather treated as some secondary objective .. eg. if one buys second wheel set anyway (for eg. winter use, or for looks), then it's worth to choose wheels that will be lighter too. Or if money is no object and every split second counts (like in competitive motorsports).