Wheel rotational weight impact on performance

jmimac351 · #1 03-05-2009, 01:24 PM

Does anyone know how to figure the impact of wheel weight on performance? I know that the weight of wheels makes a big difference but I'm not sure how much difference a few pounds makes. When you decide whether paying a big premium for lighter wheels is worth it knowing this info can help make a better decision. For instance, is going from 25lbs to 18lbs in wheel weight worth another $1,600 in expense for a custom, 3 piece wheel? That's what I'm trying to figure out.

Thanks.

panozracing · #2 03-05-2009, 06:19 PM

Quote:

Originally Posted by jmimac351

Does anyone know how to figure the impact of wheel weight on performance? I know that the weight of wheels makes a big difference but I'm not sure how much difference a few pounds makes. When you decide whether paying a big premium for lighter wheels is worth it knowing this info can help make a better decision. For instance, is going from 25lbs to 18lbs in wheel weight worth another $1,600 in expense for a custom, 3 piece wheel? That's what I'm trying to figure out.

Thanks.

CCW 3 peice wheels are $450 ea. and $150 a section to replace. I checked their site and 18x12 = 21.6lbs not bad. www.ccwheel.com I have been racing with them for years and they are great to work with and very helpful group.

jmimac351 · #3 03-05-2009, 06:27 PM

Thanks Brian. I had CCW wheels on my cobra and they are great. Just wondering whether they are worth the money performance wise over something else. I'm looking at going to wide wheels all around and the "cheap" mustang knockoff wheel don't weigh a lot more. The maker claims the 17x10.5 wheel I'm looking at is a little over 24lbs. Not sure what a 17x10.5 from CCW would be. I may call him and check. I was wondering more about what taking a few pounds out of the wheel makes for performance. I thought there was some equation like taking X amount of weight out of the wheel is like taking an exponential amount of weight out of the car.

panozracing · #4 03-05-2009, 06:50 PM

http://forums.corvetteforum.com/c6-t...s-more-hp.html

NICE FFR!!!! I drove one once and my feet are tooooo big for the footwelll....tooo bad I really wanted one! I am not going to buy a street car that I have to wear driving shoes around town. Did you build yours or have it built?

David Eastman · #5 03-05-2009, 08:03 PM

With 225 hp every oz you save will help.

David

jmimac351 · #6 03-05-2009, 08:36 PM

Due to a confluence of events I am making some hp modifications sooner than expected.

jmimac351 · #7 03-05-2009, 08:39 PM

Thanks Brian. I built mine. That's why the hp change is coming. I'm pulling my good motor out of the cobra and swapping in the 302 with a carb from the panoz and selling the cobra.

Gatorac · #8 03-05-2009, 08:59 PM

With your current schedule of track events per year it will take you at least 7 years to notice the difference in wheel mass on the performance of your car.

From what I have heard, rotational weight is worth about 4 times as much. Unsprung weight is the worst. You can imagine more mass that is unsprung when you hit a small bump in the track. The momentum will carry the tire off of the racing surface. I'm pretty sure you don't get any traction from a tire that is not on the racing surface. This will be more pronounced on tracks that are rougher. You don't live near any tracks with a lot of bumps, do you?

I say do it. I will very much enjoy passing you with your higher horsepower wider tired car.

jmimac351 · #9 03-05-2009, 09:11 PM

The reason for the change is because I decided to sell my cobra and I don't want that motor to get away. A man axes a question and he's subjected to insults and unprovoked taunting. I'm like Winn Dixie - getting better all the time.

Gatorac · #10 03-05-2009, 09:27 PM

Quote:

Originally Posted by jmimac351

The reason for the change is because I decided to sell my cobra and I don't want that motor to get away. A man axes a question and he's subjected to insults and unprovoked taunting.

You didn't expect anything less, did you?

So let's say the new wheels are 5lbs heavier each. That's 20 lbs of extra unsprung weight per corner. Hardly even noticeable.

Take every dollar you are thinking of spending on mods or upgrades and spend it on seat time and instruction. You will get faster,faster. Just ask David. He doesn't suck near as much now. He doesn't even have to point by Miatas anymore. I've seen it with my own eyes.

jmimac351 · #11 03-05-2009, 09:38 PM

Why should I pay for instruction when I have you?

How much do the BBS 17" wheels weigh? It could be that any performance advantage one might think they are getting from wider tires on "cheap" mustang replica wheels will be offset by the additional weight. And I'm wondering whether to do the wider wheel thing requires an expensive, light 3 piece wheel to make it work, ie. CCW.

jmimac351 · #12 03-05-2009, 09:47 PM

Jmmy, like I said I am only making the motor change because I want to make the cobra a running car to sell it. I need to get the price point down and not give away a good motor in doing so. I'm actually thinking of running some kind of restrictor plate. Believe it or not, I don't want to go "too fast".

Squerly · #13 03-06-2009, 06:45 AM

Damn, it's getting rough around here...

jmimac351 · #14 03-06-2009, 06:52 AM

I'm serious about following Pomroy around. That dude can drive.

panozracing · #15 03-06-2009, 07:36 AM

Quote:

Originally Posted by jmimac351

I'm serious about following Pomroy around. That dude can drive.

Lets plan a Florida event with all these Panoz's. It sounds like there is at least 5 including my 2. The only issue is that none of you can follow my brother and I around Sebring at 2:13 and down.....you will see us ever 5 laps as we pass by

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