OK, so I have my 19/20" bling bling wheels for regular street driving, and finally decide to up the ante and get some drag radials. As you know, drag radials don't come in large sizes, and I'd want a set of bling bling wheels and track wheels that I can swap between whenever I want.

So I order a set of 18x9.5 and 18x10.5 Z06 reproduction wheels, asking before purchasing how much the wheels weigh. The answer I got was "within a pound or two of stock". I also asked if the wheels were made of aluminum, and they said yes.

I received the wheels today, and the suckers are heavy! I weighed my 18x9.5 stock C5 wheel (which I still had in the garage) and it shows up at about 15-16 lbs. I weigh the 18x9.5 reproduction wheel, and it's 25lbs!

My question are this... first, is it possible the reproductions are aluminum and still weigh 25lbs? They are certainly not within 1-2 pounds of the factory wheels. Second, are Z06 wheels generally in the same weight range (sub 20lbs each?) Third, BESIDE the fact that I appear to have gotten incorrect information I based my order on, should I send these back? Are they really going to kill my ETs or handling (if so, how much?) Are other more track friendly wheels like CCWs much lighter? FWIW I paid $600 for the set of wheels so they weren't exactly expensive.

I was really excited to see the wheels show up today, 2 days earlier than they were supposed to, since I am going to the track this Friday night. But now I am not sure I should keep them.

Advice?

 

I just weighed an umounted Z06 (factory) front wheel on a shipping scale I have in my garage. It barely breaks the 10 lb. mark. I would guess the rears are a few pounds heavier as they are bigger. I have scored some great deals on factory Z06 wheels on ebay. The repros don't compare in quality.

 

Your numbers don't sound right; they sound low. Here's what I have in the C5 General Sticky:
16 lbs, front; 20 lbs, rear --- 01 OEM standard high polish
19.6 lbs, front; 21.4 lbs, rear --- 01 Z06 forged
19.2 lbs, front; 21 lbs, rear --- 02-04 Z06 cast/spun
24 lbs, 18x10.5 --- 00+ repro high polish
28 lbs, front; 32 lbs, rear --- Z06 chrome repro
23 lbs, front; 26 lbs, rear --- Z06 chrome repro

I think your scale is off by maybe 5 lbs, but yeah, I'd say your were lied to. General sales BS I'm sure, but you still have every reason to be ticked. CCW's are lighter if you stick with stock sizes, and generally the same weight if you go bigger, which I'm sure you will if you're buying custom wheels. Jongbloed makes even lighter wheels. There are the new carbon-fiber/titanium wheels that are about to come out that will probably weight 7 lbs each, but I think they'll cost around $3k per wheel, and they only come in Z06 sizes.

 

OK... so how much of a difference does the extra 40lbs of unsprung weight around the entire car make in acceleration and handling?

 

I think I heard that you can multiply unsprung weight by 4 times to get the real number..

 

From an engineering stand point, reducing the weight of a car in key areas will certainly improve performance and handling. I would stay away from the repro wheels, as you can see they my be much heavier. There are alot of quality aftermarket wheels that fit your bill. I think the 18" fronts are inefficient for you needs. They are simply too big. Take a look at the NHRA dragsters. They have giant steamrollers on the back and hockey pucks on the front. I think you got the tire issue taken care of. Don't forget, you also need to be able to STOP!!!

 

There are a few programs out there that can fairly accurately predict the car's response to changes, but for it to make accurate predictions, a LOT of data must be entered....and thus the reason for the C5 General Sticky. If you ever weigh anything else, let me know, and we'll be that much closer to coming up with a good answer to the question you've posted here.

Eugene

 

Yeah I got the same run around when I got my z06 repos too, I almost sent them back. They were 5 lbs heavier and they are not all aluminum. I called the manufacture direct and found out there are a combination of aluminum and other metals. Only after I told them a magnet sticks to them they told me the truth. What I learned from this "Dont buy repos from coh off ebay". THey dont know what they sell and arnt willing to help with shipping if your not happy and want to return them.

 

Tires are also a big factor in unsprung weight savings. Just getting rid of the runflats and going with something like the GY GS-DS3's can save you about 6 lbs per wheel. That's 24 pounds right there. That's my next mod once the runflats go bald. For the moment, I think I will stick with my OEM Thin spokes since they seem to be one of the lightest wheels available and they look good. I'm sure in a few years, there will be even lighter wheels on the market as technology progresses.

 

That's the ROT I use.......1lb of unsprung = 4lbs body weight
And with my rear tire/rim combos of 57 @ 64 lbs each I could use a diet

 

It makes a HUGE difference in terms of unsprung weight. Especially with something as large as an 18 (more weight further out from center of wheel). I had repro 2K wheels and they were heavy as *****. Maybe 10 lbs each wheel, but believe me it makes a difference. You'll probably negate any benefits of using DR's if you use those heavy *** wheels. It was so bad on the street, I SOLD the repro 2K wheels in favor of my lighter stock wagon wheels.

 

Of course then we look at the power to weight ratio.......... I have no problem these weights on the 97'
And why you should tub and get the right offset to bring the extra size/weight closer to center line

 

Right but even still that extra 10 lbs of unsprung weight per wheel makes a huge difference on other factors no matter how much or little power you have. May not apply here for running just drag radials at the strip, but the extra unsprung weight also taxes your suspension especially on bumps degrading the ride, and the brakes on decel.

As for the weight in the center, I was referring to the fact an 18" rim has most of its weight out further from the center of the wheel, then something smaller, say a 15", so the further out that weight is, the extra unsprung weight could be the same but the 18" would have more of an effect then the 15" would.

 

Repro wheels are very heavy, I know cause I bought some Chrome C6 replicas. Like you I was excited. They looked great but they ruined the ride and the car bumped steered very badly. C5 stock shocks are valved for rebound with a specific unsprung wieght in mind. Adding wieght causes problems.
I went the other way, I put my magnesiums back on and got some light wieght pirelli rosso tyres. I also put ZO6 shocks on all round to compensate for the wieght loss. During a recent track day the car performed alot better than cars with repro wheels, noticably when on the brakes and on a particularly uneven corner

 

leaftye Can you point me to some of those pgms? Might find it interesting (unless they're for drag racing, if so ignore my request)

For drag racing where it's all straight line, no bumps etc. a reduction in rotating mass will aid in acceleration because there's less inertia to be overcome. That's about it for straight line...

For road track/street like conditions, a heavier, higher diameter wheel requires more effort to resist rotation, as a result more braking force.

The further away the weight is from the centerline the greater the gyroscopic effect of the rotating weight, so there'll be a greater resistance to turn in (for a fixed width/traction scenario). Although if this is truely noticable or not I can't say (it certainly is on a motorcycle...)

As mentioned above, other handling aspects can be affected. Both from lower profile tires (stiffer) and added weight (dampening affect of shocks). The suspension suspends the car, not the tires/wheels, but with bumps etc. the extra weight can change the damping effect of the shocks.

DISCLAIMER - I'm no expert, and didn't sleep in a Holiday Inn last night either.

 

I don't get all you guys saying there is a "huge" difference..
40-50 lbs, on a 3500lb car with 350 HP, you will NEVER feel the difference..

At the track it "might be" .02+/- in ET..

I don't get what all the hubbub is about wheel weight..
Especially with our cars..

 

Rotational mass makes a huge difference in both accelerating and decelerating. Think about this example. Take a bucket half filled with water and swing it around in a circle and then stop it. Then take the same bucket filled all the way and try swinging and stopping it. Big difference between the two. While weight on the car itself doesn't make a big difference, if you have to get that same additional weight rolling and stopping every time you accelerate/decelerate, it does matter.

FYI, I believe Lou Gigliotti said that 100 lbs (non-rotational/sprung) is worth 16hp.

 

This is one of the main reasons I stick w/ factory parts (in certain areas). I chose a set of used Z06 wheels over aftermarket solutions not only based on cost, but performance of the vehicle as well.

Even though I went up an inch in width on both ends of the car, with the associated increase in tire size, I still lost a few pounds per wheel over the stock setup. Sounds like a bargain to me!

 

Here is my experience. I had a set of 18" chrome repros all around in Z06 widths. I had Pilot Sports mounted. I weighed my combo and got 60.5 lbs ea for the rears, and 56.5 lbs ea. for the fronts. I recently bought a set of 04 Z16 Speedlines from Bob @ House Of Wheels, mounted my old rears (still in great shape) and put new 17" Pilots up front. Then I weighed those. 47.5lbs ea. for the rears, and 43.5lbs ea. for the fronts. That's 56lbs. Then I sold my Corsa Indy's 29lbs ea. (I weighed them on the UPS shipping scale) and put on Borla 2-tip stingers at 19lbs ea. That's 72lbs static less and 56lbs unsprung. There really is a huge difference in the way the car handles now.

 

For what its worth here is my experience.

I switched from thin spokes w/ run flats to Z06 Motorsports ( 18 inch all around: 9.5 F and 10.5 rear ) w/ non run flat Kumos 265F and 295 rear).

I was told that the C5R ran this size wheel and tire...thats why I chose this setup. Supposedly the bigger front aids in cornering and braking.

I did notice a heavier feel in the front. I also thought I could feel the bigger sized wheels in front. It all seems normal now.

My car handles great. This is evidenced in my much better performance on familiar highspeed turns and canyon carving. I have however also done suspension mods (see below).

At the strip (12.6 @ 111) I did well with this setup. This was my first time ever at a strip. I have been told these are good results for my mods.

Could my ET's be better and my cornering faster with lighter wheels? I don't know but I have a hard time as it is keeping traction....

(again....I stay at the Ritz Hotel )