pwwatkins

I read somewhere on here that wheel weight is something like 1 pound of wheel weight = 10 pounds of car weight or 1 hp? I would assume this is at a certain mph? Is there some chart or something, what speed does this start to matter.

I just called about my wheels and found out they weigh 28lbs (9.5*18 a.z.a. Z-1's)
I was thinkin about switchin over to maybe a ssr competition 17*10.5 which is like 16 lbs.

That would be a 48 pound decrease in wheel weight. If that first statement I wrote above is true, then it's time for some new wheels.

fastcarfreak

actually i think its every 1 pound of unsprung weight is the equivalent of like 17 pounds of sprung weight.... this is why people stress to others not to buy cheap wheels because they tend to have ridiculous weights and they tend to trash our car's performance...

aznpoopy

going from 28lbs to 16lbs a wheel will be probably result in a huge huge huge change in how the car feels.

money

iTrader: (2)

28lbs is just for the wheel with out tire? damn that is alot.

pwwatkins

Yeah, that is what I was thinking, but that is what they said when I called today.

Here is another thread I was looking at, someone just chimed in saying there was a magazine that did a test with wheels that were 10 lbs lighter than stock and picked up .1 in the 1/4 mile. I'll link it in a second.

pwwatkins

https://www.rx7club.com/single-turbo-rx-7s-23/lightweight-wheels-how-much-difference-do-they-really-make-652075/

Mahjik

iTrader: (1)

My suggestion about the issue:

https://www.rx7club.com/showpost.php...4&postcount=10

habu2

Lighter wheels/tires result in lower linear moments of inertia (a good thing)

Lighter wheels/tires usually result in lower rotational moments of inertia, depending on how the mass is distributed (a good thing)

Lighter wheels/tires result in lower unsprung weight (potentially a good thing). Too much of a difference and you will need different spring rates and damper settings or your handling will be off.

My point is lighter wheels affect more than one aspect of your car's performance. You need to understand the whole picture.

Mahjik

iTrader: (1)

Lighter wheels, in most cases, also damage more easily. When I say in most cases, I mean the ones most "normal" people can afford. Even such respected magazines like Grassroots have said to pick the right rim for the right application, not necessarily for the weight.

i.e. if you are going to run the rims on some public roads where you know you'll have potholes and other issues; don't pick a lightweight "track" rim.

poor college student

1 lb unsprung to 10lbs sprung?? wtf...? that's a TON. I heard it was more like 1lb unsprung to 4lb sprung. therefore a wheel that's 8lbs lighter (26-18) you're looking at 32lbs/corner which translates to roughly 128lbs sprung weight, and i thought it was 100lbs --> .1 second in the 1/4 mi, so 128lbs shaves .128 seconds in the quarter?

not to mention the improved FEEL of the car.

Don't forget the weight of the tires too. Some tires are significantly heavier than others.

JConn2299

That's the most sophisticated observation in this thread. Generally though people are heading in the wrong direction, adding weight and making it more difficult for the suspension to control. Bigger isn't always better. The worst trend I see is that people spend a lot for aftermarket rims (and let's be honest, the main motivation is for style) and then they cheap out on tires buying a mediocre or poor brand on price or because they think the tread pattern looks "radical."

jgrewe

iTrader: (1)

There are all kinds of 'ratios' for taking weight off of rotating stuff. The ones I've heard say 1 lb off crank speed stuff is like about 15 off the car, 1 lb off wheel speed stuff is like about 4 lbs off the car. This was on a TransAm type race car so you results may vary! The lighter wheels are great for many different performance issues as stated above. The easiest way to keep them light is to keep them small, I know its not the style now but those 17's and 18's are a waste if you don't have the brakes to fill the rim or the suspension geometry to need them.