Wheel weight effect on acceleration and handling?

[THE WLF]

I'm shopping around for a set of wheels under $1,000. I'd like a 9 or 10 spoke wheel like the XXR 527's or the TSW Interlagos. My question is, will I actually notice a difference in handling and acceleration if I was using 18lb. rims rather than 21lb.? Would it be worth it to spend another $1,000. to save 3 pounds per wheel? I know that it'll make a difference, but I'm wondering if a loss of 12 pounds of unsprung weight will "transform" the way the car drives. Thanks.

 

[dquarasr2]

I'm shopping around for a set of wheels under $1,000. I'd like a 9 or 10 spoke wheel like the XXR 527's or the TSW Interlagos. My question is, will I actually notice a difference in handling and acceleration if I was using 18lb. rims rather than 21lb.? Would it be worth it to spend another $1,000. to save 3 pounds per wheel? I know that it'll make a difference, but I'm wondering if a loss of 12 pounds of unsprung weight will "transform" the way the car drives. Thanks.

See if you can find a copy of May 2012 Grassroots Motorsports issue (I'm pretty sure that was the issue.)

They did an objective test of varying wheel weights. Did it make a difference? Yes. Would it be noticeable by a butt dyno? Highly unlikely.

If you are going for the last 1/10 of a second I'd say it might be worth the extra $$, but you'll have to evaluate that extra $1,000. For street driving, my own personal opinion is no, not worth it. Again, you may feel differently.

I'm assuming we're comparing two wheels with the same diameter, resulting in the same overall tire circumference thereby not changing the final drive ratio.

 

[Hapa88]

Here's what Car & Driver found:

http://www.caranddriver.com/features/effects-of-upsized-wheels-and-tires-tested

I'm actually considering the TSW Interlaggos because of the lightweight and relatively low price. I used to have the XXR 522 which were around 20lbs F/24lbs R and noticed a butt dyno difference from my Works which were 25lbs/27lbs.

 

[Sumeronthechain]

So if I am reading that correct, obviously the lighter the wheel the better the acceleration, but you can't really draw any conclusions on the handling because the tire width has changed as well.

 

[TURBO2GO]

You'll notice weight the most on ride quality... Shocks that were designed to handle a stock 15/16 wheel don't do well with heavier wheels. So all motion control is now worse.

The second place you'll notice it is in responsiveness and during transients. Changes of motion and direction, steering feel, etc.

The third place is in acceleration, and the 4th and last is in braking. The effects are most noticeable IN THAT ORDER.

Other factors come into play. The more torque you have, the less it matters on acceleration. The more capable your dampers, springs, and sway bars, the less the effect on ride and handling.

Where the rotating mass is at also matters. If its more towards the center, like lugnuts, it matters less. If its towards the outer, like the tire, it matters more. The tire weighs as much as the wheel. If you stay small, and the tire stays small, the effect is less because only wheel weight has increased. If the wheel weight has increased because it's a bigger wheel, requiring a larger tire, you've doubled the effect or more.

So this is not a black and white question. The worst part generally is what few talk about. It is the "lightness of feet" that is lost. It won't translate to big numbers unless you are on a track, but the car simply feels more sluggish.

 

[TURBO2GO]

Another thing I should have said is that don't forget that in GENERAL, the extra $1000 also gets you better built wheels, not just lighter ones. So things like their resistance to bending, their uniformity of shape, and the longevity of the finish usually also improve. I think $1000 for a set of NSX wheels is too cheap. There are exceptions, and some will disagree, but as a general rule to me, decent NSX wheels start at 2K and up.