It's unsprung weight the hardest to lose and the most benificial. The car should stop accelerate and handle better, what that looks like on a spreadsheet is individual to the particular car. I'm unaware of a formula to calculate what gains to expect but with your car as a baseline back to back test will net you the results. Can your backside tell? I have no idea. But 36lbs of unsprung is significant

The guy want new wheels, so let him get new wheels. He is not building a race car. Yes it makes a difference in performance.

A magazine did a test on this in the 80's, a 15 second small block streetcar picked up .25 and 3 mph in 1/4 mile on the time slip going from 15" rallies to weld wheel draglites. Same tires and traction.

Its unsprung AND rotating weight... win and win. Thats weight at the very end ov the powertrain that your engine has to spin. A heavier axle costs performance, a heavier driveshaft costs performance, you dont think 8 extra pounds a wheel... spinning at a far greater diameter (thus speed), demanding far greater torsional strength is not going to cost performance? And a reason why so many teams dont go nuts on re-sciencing the rollers is because its largely been done already. Light wheels and tires are readily available, and more reasonable in price than years back. To get beyond what you see out there requires an investment far beyond return. Also, some stock car stuff is as light as its allowed to be, or as light as it CAN be. Far more stress on that NASCAR wheel than a local roundy-round wheel, or the street. You can buy 19lb circle track wheels, but the actual NASCAR ones are far heavier i believe.

If strength did not matter, we'd all be running those ugly ol' Weld Drag Stars...

fire trucks have aluminum wheels because firemen like them shiny [not that there is anything wrong with that]. city buses have steel wheels because they run into, and over, all kinds of stuff that would trash aluminum wheels in quick order. plus, i believe steel wheels are cheaper than aluminum and don't require constant polishing that will save the city big bucks in their yearly budget. garbage trucks are steel wheels for the same reason and i would hazard to guess they start and stop way more frequently than city buses.

Fire trucks have aluminum wheels because the departments have ridiculous budgets that they have to spend.

and that too, although it seems the departments out in the sticks are always having fund raisers. but if i had need of their services, i don't think the budget money would be my first concern.

1. Any CDL driver that has any record of running over stuff on any regular basis would promptly be dismissed/transferred, and if indeed that was the case, a $400? tire plus labor would be the first casualty, and I don't think the record would support that thesis.
2. Class 8 OTR and others have a long history with billions? of miles and alum wheels have no greater known failure rate then steel ( they are forged 2024 aircraft alum).
3. Alum wheels don't require any polishing, don't require any rust protection, and are fine with only the normal wash cycle maintenance.
4. The taxpayer who subsidizes the city buses on their fuel guzzling, every block starting and stopping, would be very rewarded in the 200?lb rotating weight reduction, both in fuel and brake tire wear costs on each vehicle, if the city buses swapped their steel wheels with the over budgeted first responder fire departments, and let the fire depart when not fighting fires, visit the bus depot and polish their new alum wheels.


Edit, went to check my sources, looks like Alcoa, a leader in alum truck wheels has changed over Aircraft 2024 to 6061 forged wheels, likely for cost and better corrosion resistance, not sure it matters much, as the track record is still solid.

In theory, yes. However I have yet to hear real-world results from one person who claimed to see gains in the 1/4 mile that were anything more than the result of losing the equivalent amount of weight from anywhere else in the car.

it's kinda obvious you haven't watched too many buses in cities like pittsburgh with the narrow, twisty streets, and have not been to the land fill and watch garbage trucks in action. and i'm certainly not debating your other points which are valid in every aspect. just stating what i have personally observed over the many years i have been on this planet. and it is really no comparison to argue paid fire companies vs volunteer fire companies, which i have first hand knowledge. carry on.

No I have long term daily experience seeing what you mentioned, my main point on wheel abuse, you would see and pay for tire repairs/replacement way before, and in much higher frequency then you would wheel damage driving caused abuse. The tires would be the Canary in the coal mine.

It's funny to hear the debate that it doesn't matter.

1) Put a 10lb weight belt around your waist and go for a run.
2) Add 2.5lbs to each wrist and both ankles.

Now which case do you think you'd be able to run faster?

i really didn't think i stated that it didn't matter. just "sometimes", for what ever reason, "somebody" decides that steel wheels are better to use than aluminum. take the post office for example. [please?] how many aluminum wheels you see on mail jeeps ? none here. fedX and UPS. all steel here at this hub and that includes the OTR rigs. no need to waste time and materials [paint and stripes on the outer rim edges] on alloy wheels, plus the savings on fuel. police and sheriff vehicles ? none around here, including the state police. lots of miles and fuel used, could use the extra money someplace else for sure. and as others have said, the time slips and "butt meters" show the same results with either in some instances. i'm not disputing or arguing for or against either. just observations. and to think i am accusing city bus drivers of running over everything and anybody is ludicrous. just not too many open man holes, tall curbs, street drains, curbs with street drains, etc. on the open roads. tires are certainly the "canary in the coal mine". and i can't run any more, plus i walk with a cane, so i'm not gonna put weights on and do a marathon.

sorry if i ruffled any feathers. that was not my intent.

You couldn't be more wrong.

Rotating weight is literally a flywheel. It has to be accelerated and decelerated in order for the car to perform.
Totally different than static weight.

Race teams may be ruled constrained in what wheel composition they may or may not use.

Really?

The 4" skinnies they run for front tires ring a bell?

Back tires are optimized for traction, maybe at the expense of possible weight savings.

Of course your examples are straight line guys anyway, the only handling they care about is making the turn back to pit row. Anyone interested in handling and considering new rims would be smart to look at weights as well.

Weights on the wrists and ankles examples should end this.

Anyone ever run a spin tire balancer and see how hard it works to start and stop a heavy wheel/tire? Even larger diameter alone will change this, it is further out from center, more centrifical force.

I hope the underlying point I was trying to make, wheel inertia matters little with constant speed, but anything that starts, and stops, especially frequently, consumes power accelerating (fuel/hp) and has to give the stored energy back up under braking (heat/brakes/tires). Thinking any municipalities can see the benefits of large Alum maintenance free wheels on high use vehicles, is obviously never going to happen in my lifetime, unless looking "shiney" becomes the in thing outside the fire dept. Our understanding of why is likely where we most differ.

[ Moparts Family Site - Keep it Friendly ] does garbage and fire trucks have to do with this? So many outside variables.

The answer is lighter wheels have such a minor gain that most gains will go unnoticed but here is a fact, they will not hamper the performance. It brake better, turn better and for sure accelerate better.

I like the ankle weight example and here is another one for those who are not convinced. Jack your rear wheels off the ground. Remove the rear wheels and drums. Punch the throttle in neutral, punch it in gear and repeat with the drums and wheels on. The throttle response should be a great lesson for you.

Maybe to help those with limited imagination envision a problem and/or a like solution?

Care to share some of those "outside variables" that negate the correlation, if you can?