Tried a quick search- no luck: Does weight of wheels really make much of a difference?

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burrpenick

burrpenick

'69 Barracuda
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Seems like it being unsprung weight that it would, but how? Does the car ride better over rough surfaces w/lighter wheels? Stop and start better? I once thought that most alloy wheels were not that much lighter than the stock steel or rallyes, so whats the experts say......and some hard numbers would be nice to see. And throw in aluminum and mag wheels too? And how about the drag wheels that are even lighter- and maybe not street legal if one were concerned........
 
Doubt fuel mileage will & increase. Or lower ET's But it's gotta help something?
 
1lb rotating = 4 lbs Sprung weight..
It makes a difference in both mpg and et. How much depends on many things...
 
ANY reduction in weight is a good thing. Don't over think this. just get some light wheels and know you did a good thing.
 
It's not just the difference in unsprung weight, but also that wheels must be accelerated and decelerated in two modes of kinetic energy, linear and rotational. So it takes a lot more energy to accelerate or decelerate a wheel than the rest of the car, which must be accelerated only in linear mode.
 
Actually, I think the REAL question is, "can you substantially improve" the situation? And I would guess "no." Not unless you are willing to spend lots of money on specialized lightweight wheels, and they might compromise strength.

But yeh, "lighter is better"
 
Here a good analogy
Grab the kid’s bike and spin the wheel as fast as you can. Now stick your fingers in the spokes.

Now try the same thing with a mountain bike.

This is purely hypothetical, i dont really expect you to do it.
But rotating mass is relevant, the heavier it is it would be harder to accellerate and to stop.
 
Consider this. Generally speaking, the rule of thumb is, for every 100 pounds, you knock off 1/10 of a second. At least.......I think that's right. My memory taint what it used to be. I tell you who can verify it...... @70aarcuda Hay Tony, is my formula about right?
 
RustyRatRod said:
Consider this. Generally speaking, the rule of thumb is, for every 100 pounds, you knock off 1/10 of a second. At least.......I think that's right. My memory taint what it used to be. I tell you who can verify it...... @70aarcuda Hay Tony, is my formula about right?
Click to expand...
All good info, and nothing surprising. Someone was talking about how Alum/Alloy wheels just 'felt' better while driving, not to mention being lighter, so I wondered if that was true. I guess most of us just put new wheels on and dont weigh them first. Just a little digging on the net shows that a 15x8" steel w/weight around 30+(without centers and trim rings- probably another 2.5lbs?) and the same in Alum/Alloy around 20- thats close to 50 lbs!
 
RustyRatRod said:
Consider this. Generally speaking, the rule of thumb is, for every 100 pounds, you knock off 1/10 of a second. At least.......I think that's right. My memory taint what it used to be. I tell you who can verify it...... @70aarcuda Hay Tony, is my formula about right?
Click to expand...

Wtf rusty! I don't think anyone can really answer this question with your new avatar staring at them. :thumbsup:
 
To keep it simple. Think of the tire/wheel assembly as a flywheel. How do you think the weight of a flywheel affects acceleration and deceleration. Think..for acceleration you would want a light flywheel, it will rev quicker using less power. Think..climbing a hill, a heavy flywheels momentum causes the car to want to keep going. One of the first things that someone who puts larger tires and wheels on his 4x4, suv etc...has to do for safety is to install bigger brakes to stop it. Why ??
 
An object in motion remains in motion until affected by an opposing force.
100 lbs. lost=.1 second decrease in ET is what I was taught.
Less unsprung weight allows the suspension components to function more to their ability.
 
burrpenick said:
All good info, and nothing surprising. Someone was talking about how Alum/Alloy wheels just 'felt' better while driving, not to mention being lighter, so I wondered if that was true. I guess most of us just put new wheels on and dont weigh them first. Just a little digging on the net shows that a 15x8" steel w/weight around 30+(without centers and trim rings- probably another 2.5lbs?) and the same in Alum/Alloy around 20- thats close to 50 lbs!
Click to expand...
Depends what your doing.
To get useful info on wheel weights, you need to look up the exact model and size.
I've posted what I've weighed about 2/3 of the way down this page.
67 Barracuda Autocross Tech.
Doesn't include the 235/50R15 R888R since I haven't updated the website in while, but will give you a feel for the range.

Lightweight rims flex more. At some point the trade off isn't worth it, even for road racing. The flex effects the tire and in some materials eventually can cause cracks to develop in the rim
Steel rims can also fail. Scott Harvey recommended doubling up the centers for rally prep. The Hemicuda raced by Chrysler France broke one of the rally rims during an event. The car was run in a class that required stock equipment. They had been racing it at least a year at time of failure. The point is that under the repeated stresses of racing even a steel rim can break.
 
Mattax said:
Depends what your doing.
To get useful info on wheel weights, you need to look up the exact model and size.
I've posted what I've weighed about 2/3 of the way down this page.
67 Barracuda Autocross Tech.
Doesn't include the 235/50R15 R888R since I haven't updated the website in while, but will give you a feel for the range.

Lightweight rims flex more. At some point the trade off isn't worth it, even for road racing. The flex effects the tire and in some materials eventually can cause cracks to develop in the rim
Steel rims can also fail. Scott Harvey recommended doubling up the centers for rally prep. The Hemicuda raced by Chrysler France broke one of the rally rims during an event. The car was run in a class that required stock equipment. They had been racing it at least a year at time of failure. The point is that under the repeated stresses of racing even a steel rim can break.
Click to expand...
Thanks for the chart. NO racing here! Very little road miles either, so I'm OK w/light! Surprised that your chart shows the weights so close- that quick search I did claimed 30lb to 20 for the alloys.
 
burrpenick said:
Thanks for the chart. NO racing here! Very little road miles either, so I'm OK w/light! Surprised that your chart shows the weights so close- that quick search I did claimed 30lb to 20 for the alloys.
Click to expand...
Thats why I said its very specific to both size and wheel. I suspect if ARE makes a 17x7 'Ansen' slot it will weigh a bit over 20 lbs. Cast aluminum tends to be heavier than forged, but a lot depends on design and manufacturing.
Few people ask about wheel and tire weight outside of racing, but I think you're right to factor it in when making decisions about wheels.
 
There used to be a website called wheelweights.net with a large list I beleive was crowd sourced. Just looked and its gone now. :(
 
If you are running a moderately powered car on the street you probably wont notice . But if you are racing a high horse car and counting 100ths of a second it really does make a difference.
BTW...alloy wheels are not always lighter than steelies... pick up an old Keystone classic sometime. Ufda!!!! thats a heavy wheel!
 
That’s because there is a lot of steel on the Cragar Key stones. They list the wheels construction.
 
rumblefish360 said:
That’s because there is a lot of steel on the Cragar Key stones. They list the wheels construction.
Click to expand...

Pretty much all of the above^^ .
I have even thot of using heavier wheels to add some resistance to help spinning at the starting line. Would not be drastic, but still there.
 
rumblefish360 said:
That’s because there is a lot of steel on the Cragar Key stones. They list the wheels construction.
Click to expand...
As were many such as the KH 'recall' wheels and the Crager SS. They use Al centers, steel rim.
An Al/steel Crager SS in 14x6 weighs in about 21 lbs.
 
If lightweight didn't matter then why do serious race cars have lightweight components?
 
The average driver wouldn't notice the difference. I race motorcycles so another factor to consider is how the suspension reacts to the weight as it moves through its travel. So, yes, weight makes a difference but only in more extreme situations. Remember, some stock factory wheels on Cordoba and Imperials weigh a ton.
 
A ton? I had no idea they weighed that much, no wonder the overall car was so heavy. Is that each, or all four?
 
Tooljunkie said:
Here a good analogy
Grab the kid’s bike and spin the wheel as fast as you can. Now stick your fingers in the spokes.

Now try the same thing with a mountain bike.

This is purely hypothetical, i dont really expect you to do it.
But rotating mass is relevant, the heavier it is it would be harder to accellerate and to stop.
Click to expand...


Actually, rotational inertia is an exponential factor of the radius, so the change in diameter does far more than any change in mass.

A heavy wheel versus a light one of the same diameter is a better comparison.

If I remember correctly, anyway.
 
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