Wheel weight.. does it Matter?
 

Im looking into getting some 17x9 wheels. Been noticing all these beautiful wheels that weight 21-22lbs! Then there r some other, eh, alright looking wheels that r way expensive or alright priced that weight about 17-18lbs...

I'm curious to know, for knows of u that have both, or have had, does it really matter? Do u feel the weight of the wheels actually make it feel a lot different? Faster? Smoother? Grippier? Slipperyer? Or anything at all?

Plz be as detailed as possible w ur replies. I'd really like to make a decision on wheels & I cant afford to buy both. Thank u everyone

By the laws of physics? yes. By a lot? no. It may reduce fractions of a second during drag races. But for auto cross and actual track driving, it will definitely help out on your time.

Lots of people exaggerate the impact of unsprung weight on performance (wheel weight snobs).

That said, yes heavier wheels will decrease your acceleration, road handling, and increase your braking distance.

The general inaccurate rule of thumb is 1lb of unsprung weight is equivalent to adding 10lbs of sprung weight. So if you put 30lb wheels on your 86 (not including tires), then its like you just added 400lbs of weight to your car. To put this in perspective, imagine how many people it would take to equal the number and how your car would drive with them in the car.

So yes the unsprung weight snobs are right, just wish they didn't rub it in everyone's face all the time. :)

It affects overall suspension performance, handling, and braking.

The best weight reduction for overall performance of your car that you can do is a light weight clutch and flywheel.

My last car had a 8lbs Flywheel and smaller diameter 7.25" clutch, the entire assembly weighed 16lbs while the stock flywheel and clutch weighed over 45lbs made a huge huge difference in the overall performance.

Daily driving, to and from work, groceries, school... Put what ever you want on it, it is your car do what you like :)

All other considerations aside, yes it matters. But overall you need to ask yourself a few questions. Are you competing for tenths of a second? Do you have enough driving prowess to even notice the difference? Is the cost of a true lightweight wheel worth it? Could you make up those tenths in other ways first?

Sure if you put some 40lb chrome wheels you are going to notice but if you're just an average joe looking at some 18" wheels compared to 17" don't stress, get what you like.

RPF1s may be lighter but I couldn't stand to walk to my car and see them everyday.

That figure is incredibly exaggerated. It's more like 1.7x for wheel/tire, nothing like 10X! I.e., Increased wheel/tire weight by 10 lb. is like increasing overall weight by 17 lb, not 100 lb.

Sounds a little exaggerated...

BUT...

Go check out the ENKEI RPF1 on www.enkei.com/rpf1.shtml

This is the exact quote off the enkei website:

"EVERY POUND OF UNSPRUNG WEIGHT SAVINGS HAS THE EFFECT OF REDUCING OVERALL VEHICLE WEIGHT BY 20lbs."

20 pounds!!!

This is a claim from a company who builds wheels for F1 teams.

Are they exaggerating? Maybe a little... but they seem to know a thing or two.

And don't forget about tire weight which is even MORE noticable when reducing than even wheels because that spinning weight is the farthest out from center.

Ultimately it depends on what you intend to use your ride for... track or street and how much you are willing to spend.

Cheers

I guarantee that claim is from the marketing team and not the engineering team!
The only thing they can be talking about is the ratio of sprung to unsprung masses being about 20:1, but the claim is untrue. Saving 10 lb unsprung mass will not make the car behave like it's lost 200 lb.

Since they refer to "unsprung mass" and not rotational, I don't think they're talking about acceleration. In any case, the statement is simply not true.

Regarding the effect of reduced rotational mass being greater at the tire because its mass is further out, that is true, but it's still not anything like even 10:1, let alone 20:1. I think the 1.7 I came up with was for the tire only, might have been for wheel/tire. It would be less than that for the wheel, either way.

edit: 1.7 was for the wheel/tire. Tire by itself ~1.9x, wheel ~1.5x.

Any seasoned engineers on here care to chime in?

I *am* a "seasoned engineer". I've done performance models for road vehicles including rotational inertial effects.

Ok... wasn't expecting that one.

Maybe we should start looking for an aggressive law group to represent tuners vs. enkei?

:popcorn:

Every time I see the sprung vs unsprung weight comparison, the number is different. :D

In the end this is how I see it. If I find a wheel that I like that is lightweight as well, that's just a bonus. Otherwise, if I want some heavy wheels for the road, so be it. I can always buy a second set for the track if I wanted to.

Lighter wheels and tires do make a difference.. Whether its cost effective or not is up to you and how you use your car.. For everyday street use.. You most likely will not see much benefit and the money spent can be used elsewhere for bigger gains in performance. Some lightweight wheels are also compromised when it comes to durability, so make sure you don't cheap out on a set that can fail on you at the worst time. Since these cars do not have "fat" heavy wheels/tires to begin with, there are other areas that you can eek out more performance gains first with less money. IMO.
I'm loving the wheel and tire size on these cars! Coming from a corvette with its wide fat ass heavy wheels and tires makes this car feel so much more nimble and responsive.

You will feel a significant difference in acceleration the farther from stock you go (~21lbs). I went from 23lbs to 29lbs (both oem) wheels on my TDI and it accelerated much worse and lost 3mpg. Just food for thought. Stay under 23lbs with this car.