Weight of wheels and DD's
 

Been looking at various wheels and like the replica ZR1's because they look factory. Wheels are a matter of personal taste, and I don't care for all the fancy alternatives available.

Got to thinking about the weight of the wheel (and don't forget bigger tires) and how it would affect a street car, especially one that is a daily driver.

So I did some checking and found the following:

OEM 16" 5 spoke weighs 19.5 lbs.
235 55 16 tire weighs about 25 lbs.
OEM 17" SW6/ZR1 chrome rim weighs 20.5 lbs.
275 40 17 tire weighs about 30 lbs.
Replica ZR1 painted 17x9.5 rim weighs aprox 25 lbs. (as per manufacture phone call)

The lightest wheel tire combo is the OE 16" 5 spoke w/235 50 16 totaling aprox. 44.5 lbs per wheel/tire.

Upgrade to an OE SW6 17" rim and the wheel/tire combo weight jumps to aprox 50.5 lbs per wheel/tire.

Upgrade to an replica zr1 17" rim and the wheel/tire combo weight jumps to aprox 55 lbs per wheel/tire.

So the heaviest wheel/tire is about 10.5 lbs heavier than the lightest OE wheel/tire.

I have upgraded wheels/tires on almost every car I owned, and never noticed an impact to performance due to the added weight. I have noticed the increased weight just from changing/installing the old/new tires. Yep, most after market wheels are heavier, and fatter tires weigh more than skinny tires. Gee, who would have thought.....:mrgreen:

But now knowing that buying replica/aftermarket wheels and tires will add about 10 lbs per wheel/tire, it makes me wonder if there is an impact I might actually feel. Especially in light of changing the steel drive shaft to aluminum made a noticeable difference under very specific conditions. That was about a 10 lbs savings in rotating mass. Now heavier wheels/tires could add as much as 42 lbs to the rotating mass of the wheels.

Any one done a wheel/tire upgrade and notice a loss of performance or change in performance due to the extra weight?

How about shock/spring performance with the bigger weight hanging outboard?

Yup, ask any guy who threw 315s on replica ZR1s how the acceleration and braking felt after running stockers. You can def feel a change.

Well, that is a bit extreme, but it is well worth asking.

So, as per LTSlow, who with 315's noticed a difference in handling after installing them?

:lol:

kirkevil went from stockers to replicas and he mentioned he noticed a difference.

i did. i bet salad shooters are the lightest oem wheels. you also have to look at the diameter of the wheel compared to the ds. the larger the rotating mass, the more of an effect. look at drag and road race wheel weights.

If your going to get zr-1's try to get an oem set the replicas don't seem to hold up as well. My chrome zr-1's look great and there 9 yrs old now I've seen replicas with the chrome peeling off and they weren't even half as old as the ones on my car.

I avoid chrome wheels on a DD just for practicality. Even the best chrome gets crappy when exposed to road salt, and curb rash is forever.


I'll do a search on kirkevil and see if I can find his thread discussing the weight issue.

BTW, when I went from 235 to 255's on my 96 Camaro, that was just a tire weight increase of about 4 lbs a tire, and I couldn't notice anything.

Thanks.

i noticed a big difference when i went from chrome 16's with 245 tires to draglites wit 275's, and as far as curb rash goes it doesnt just happen to chrome wheels

I noticed a significant difference going from stock 16s to 17x9.5x11.5 ZR1 replicas. Feels sluggish from a dead stop trying to overcome the added inertia force, and same from a roll. Braking was only slightly worse. If I were to do it all again I would have gone with some factory vette rims.

I never actually weighed the rims, but the rear 17x11.5 w/315s have to be close to 50lbs each, and the front 17x9.5 w/275s feel like 35ish.

Just out of curiosity, what do you think happens when chrome wheels rub a curb?

According to OEWheelsllc.com, when I spoke to them on the phone they said the 17x9.5 and 17x11 weigh just about the same, 25 lbs each. I asked how that is possible when one is 1.5" wider, and he said thats just the way it is. Okey Doky....

Anyway, OEWheels sells the rims with sumitomo tires, and according to sumitomo literature (regardless of whether or not you like them) their tires weigh 30.8 lbs for the 275, and 33 lbs for the 315. So even the heaviest wheel tire combo is 58 lbs, vs 51.3 for the factory 17 setup. Thats 6.7 lbs more than factory for 315's.

Doesn't sound like a lot, does it? I wonder if OEwheels is giving accurate info....

If you say you felt a difference, I believe you.

And yeah, salad shooters are probably the lightest, but they are also the least desirable appearance wise. :mrgreen:

i have had my hands on a number of different wheel sets and i can tell you they feel significantly heavier. i think its going to be more than 10lbs but can't say its a fact.

sumitomo's are garbage IMO. many better tires out there.

he meant it doesnt JUST happen to chrome, as in it can happen to all wheels

I used sumitomos as a weight reference because they list them down to the tenth of a pound. Some manufacturers don't even list weights!

Yea, I was thinking the same thing, my OEM rims weigh next to nothing compared to aftermarket ZR1s.

The 17x11 do weigh more than the 17x9.5, especially with tires. Theres definitely way more than a 10 lb difference between my stockers and my zr1 replicas.

i feel like my 17x11 or 10.5'sTTM's with the 315 are very light. I was pleasently suprised the first time i took em off.

This weekend I'll weigh one of my oe 5 spoke 16" w/235 and post the weight.

Kirkevil, can you weigh one of your 17x11 w/tire? Just use a bathroom scale if you don't have anything more accurate. I would appreciate it.

Anyone else want to weigh a wheel/tire and post the weight, it would be a great way to start a tire/wheel weight database here.

:nod:

Mark, I will get a rough weight for ya tmmr of a OEM ZR1 with MT ET street tire on it.

Going to a lighter wheel, I did notice a nice difference in the ride when I took off my stock 5-Blade Formula wheels and put on the black 16" Trans Am Diamond Spoke wheels (which I have been told were the lightest wheels ever for the 3rd Gens) that they weighed 16 lbs each.

I'll see if I can find a scale some where here but it may take a few days Haha

Just to show some #s on weight change, since #s are better than buttdynos:

New Super Chevy has an article on a new SS they have been modifying. This month they dropped the wheels and brake size. They wanted 17s on it to use tires with more sidewall. As with most mods, there is more than 1 change happening so it is not exact apple for apples. Here is a summary.

Front:
Removed
OE cast front wheels: 20x8, 245/45/20 PZero - 64 lbs each!
OE front 14" brakes
Added
4th gen front brakes
New 17x4 Bogarts with 4.5/26-17 tires:
front wt savings - 100 lbs
(the skinny tire alone should help some with less resistance)

Rear
Removed:
OE cast rear wheels: 20x9, 275/40/20 PZero - 68 lbs each!
OE SS 2010 SS rear brakes
Added:
2010 V6 rear brakes
17x9 SLP 4th gen 5-spokes and 274-40-17 hoosier d/rs - 34 lbs each
rear wt savings - 82 lbs

Total wt savings - 182 lbs - all unsprung

Running at atco they dropped:
60' time by .06 (1.86-1.8)
1/4 ET by .19 (11.81-11.62)
MPH up by 2.06 (199.27-121.33)
(last test used nitto 274/40/20 d/rs, so the trap gain was not all tire)

Those OE sizes are ridiculous. But I digress.

It appears no one makes 'skinny' 18s to clear the OE 14" rotors, thus the reason they killed the braking on this boat. De-braking is not for me! Especially in a 4000 pound car driven on the street.

I think the technical term is MOI - moment of inertia. Can any of you engineering students maybe expand on this? My humble knowledge is it takes more energy to get a heavier wheel moving and more energy to stop a heavier wheel. So there is zero question lighter is better.

So the practical question is saving a few lbs on a street only car really worth it? Probably not. Unless you are shedding a big pile of weight. Is it worth it on a car that is regularly raced - drag or auto-x? Sure.

Not to disrail Mark's thread, but at basic, its like a engine flywheel. If you can get it going, it makes the engines job less and allows it to tackle load shocks easier as well, however it does take a lot to stop it... a heavier object requires more force/power to get it moving/rotating.

For wheels/tires, a lighter combo would be much better for stop and go because your engine does not have to work hard to get them moving, but if you were strictly highway driving there may be a slight benefit to having a heavier wheel as it will naturally want to keep rotating, so you may coast more etc.

yep, I agree that heavier is worse. Especially when its an unsprung rotating piece. But even GM was able to put aside a nominal weight increase (even in light of the potential law suits from any unsafe/increased braking distance) in order to get fatter tires on the car. AKA 16" vs 17" factory rims.

Keep in mind there were no changes to the brakes when wheel and tire weight increased.