How much effect is four pounds per wheel

[Mid_Life_Crisis]

Performance experts please tell me, how much of a difference in handling and/or acceleration do you expect to see by losing 4 pounds of wheel weight.
I know the suspension should become more responsive due to reduced unsprung weight, and theoretically the reduced rotating mass should improve acceleration. The question is, will anyone but the most die-hard racers notice the difference?

 

[tsunami]

yes you will notice 4-5lbs at each corner in regular driving. at least thats what i have been told by other sites and this site as well. i lost about 6-7 lbs at each corner and even my gf says she notices the difference from my winter to summer wheel/tire set up.

 

[njaremka]

on the three, you might not notice so much. on my protege, 4-lbs per wheel made a subtle difference in acceleration - made it a little smoother. your fuel economy will increase slightly too from it.

 

[tandman]

I took off 6lbs per corner and I noticed a huge difference.....well you can feel the difference. Taking off I noticed it right away. Gas mileage went from 26 to 30mpg average...seriously.

 

[SwampAss]

My wheels are almost 6lbs lighter per wheel than stock. Gas mileage up, performance up, wheel bend down

 

[ForceFed]

You will notice.
That is all.

 

[MS3077]

It's hard for me to comprehend how about 16lbs of total wheel weight would really make that much of a difference. What is it from a 1/4mile standpoint? .2tenths? Does anyone have proof backed by #'s or creditable / realiable sources? I hear a lot of "You will notice, It makes a difference, etc" But no hard proof.

So if someone went from the 24lb stock wheels to say 18-19lbs wheels the improvement in performance would be?? Examples....??

 

[MS3077]

The weight of the car is still bearing down on the wheels

 

[SwampAss]

you need to learn the affect of "rotational mass".


See also: Sprung weight and unsprung weight

 

[MS3077]

Sure but this "rotational mass" is still being bared down on my weight of the car. Not only that we are only talking but about 16lbs here. I just don't see how there would be massive gains from this. I believe gains from -16lbs of unsprung weight (Talking about the wheels ) would result in "minimal" performance gains at best.

Again, who can answer post #7?

 

[NCZ13]

its not 16 lbs from the overall weight of the car.

its 4 lbs less of the rotating mass.

similar to getting light weight pulleys.

lighter rotational mass means less load on the engine which leads to less energy wasted, which makes the engine more efficient.

 

[ericrapp]

I have read the theory on this many times and can barely understand it. But it always seems to end the same. This amount of weight loss in the wheels should make a performance difference. in theory. To the drive wheels

 

[MS3077]

its not 16 lbs from the overall weight of the car.

its 4 lbs less of the rotating mass.

similar to getting light weight pulleys.

lighter rotational mass means less load on the engine which leads to less energy wasted, which makes the engine more efficient.

Yes I understand the theory. My question is how much of a difference from real world experience. Not just "It feels better" or "It seems to pull harder now" Any backed by #'s? I'm just trying to figure out if it's really worth spending about 1200+ bucks on a new set of wheels.

 

[MS3077]

Sadly I don't think anyone will back this theory up

 

[turbolife]

Sadly I don't think anyone will back this theory up

Think about it from a pure physics point.

Brakes work less to stop less weight, the motor works less to accelerate less weight to the same speed, springs and struts work less to keep the tires planted.

 

[MS3077]

Think about it from a pure physics point.

Brakes work less to stop less weight, the motor works less to accelerate less weight to the same speed, springs and struts work less to keep the tires planted.

Sure but they aren't working much less at all.

Can someone show a time slip / track times, anything showing the added performance benefits of wheels weighing in @ a whopping 4-6 lbs less?

 

[dtp03]

I've done weight reduction on my last vehicle. I went from a stock weight of ~2800 to 2650 track weight. Which included interior weight loss as well as lightweight wheels AND TIRES and upgraded the suspension to new springs and struts. Track times went from 15.2 to 14.7 that also was adding a CAI.
From a quarter mile point of view it probably won't help too much considering every 100lb of unsprung weight nets you about -.1 seconds since you're only talking about 16lb sprung weight

 

[SNike05]

Very good info
http://www.mazda6tech.com/index.php?option=content&task=view&id=16&Itemid=32

 

[MS3077]

Very good info
http://www.mazda6tech.com/index.php?option=content&task=view&id=16&Itemid=32

+1

That's assuming the larger wheels weigh the same, which is often impossible. With a larger diameter wheel comes exponentially more surface area needed to create the outer edge of the rim, which is the worst possible place to add weight. Increasing wheel diameter AND increasing weight (even if only a modest amount) will produce rather noticable drawbacks- you can loose 1-2 car lengths (or more) in a 1/4 mile race. Going with wider wheels raises the amount of metal required too, although it does so only linearly.

This is the kind of info I was looking for! Time to start putting away the pennies...

A set of light weight 17's would def be the way to go.

 

[Vord]

another forum I use gives an excellent explanation on this. It also provides a spread sheet that will tell you exactly how much torque it will take to get the same times (0-60, 1/4) with a heavier wheel.

PM if you would still like it.

As a matter of the fact, the file it self is the same one as the mazda6tech site. none the less, they have a discussion you maybe interisted in. I don't think anyone has real world times or numbers, but they will provide you with a nice hypothetical one!