Z06_BluByU

guys.. I'm having trouble deciding on a set of wheels for my car.. I've narrowed it down to the Motorsport C6Z06 wheels (black w/machined face - 26lbs each) or OEM speedlines C5 ZO6 (chrome - 21 lbs each)..

I like the way the motorsport wheels looks better (pretty mean) and was wondering how much they would affect the performance.. is this one of those situations where only a true race driver (9/10th-10/10th guys) would appreciate or notice the difference?

I've been to a few HPDE's and my goal is to do 5-10 more in the next 12 months..



I suppose I could run a PS2 tire (which saves 5lbs over the stock goodyears) to compensate..

I like the looks of these wheels.. (motorsports)


also, any comments on motorsport as a manufacturer or the difficultly of keeping the rivets clean (I already have a black car)..

thanks!

John Shiels

take a brick which most weight 4 lb. and yank it up and down fast as you can you will know the difference. Really comes down to performance or looks as a choice. Racers look to knock off an ounce.

AU N EGL

Clean wheels used on track just does not happen. They will get very very dirty.

I just spay with a hose, spay on Armor All Aluminum wheel cleaner. Take a damp rag and wipe the wheels down. Hose them Off and inspect for cracks.

Remember each pound removed from rotating wt( unsprung wt) is about equal too removing 6 1/2 pounds out of the car. ( sprung wt)

So 5 lbs extra per wheel = 32.50 x 4 = 130 EXTRA pounds. Can you fell an extra 130 pounds on acceleration? YES you can. Even more soo under braking loads.

That is assuming your going to 18" all around. 19" rear wheels loose about 10 hp over 18" wheels. the Wt is farther from the hub.

Now just for doing occasional DEs having fun, and good looking wheels Go for it.

0RAAMaudio

ALLOT!
The lower the weight, better braking, acceleration, suspension works better, easier on the brake temps, easier on axles and drivelines, joints, just does not end!

I can feel the difference in just a lb or two

Rick

tcmc5

I doubt very much you'd notice a difference in performance unless you're a skilled driver timing laps. What I'd be more concerned about is the strength of the wheels. They're likely Aisian made and, though heavier, probably not as strong as the OEMs.

Z06_BluByU

is there anything lighter than the OEM C5ZO6 wheels (19.5 lbs front, 21 lbs rear)?

mgarfias

CCW's track setup (classic) is like 18lb in an 18x13.

TedDBere

Yes. See sig for hint....

Z06Fix

what do the T1 spec CCW's weigh? 17x10 17x11

thehammer69

SSR comps...hard to find though.

rustyguns

Huge!!!!!! rotating mass= 4 times the weight! i run light rims on the track and heavy repos on the street and suspension is much different!

AU N EGL

Give you an idea

my CCW CLassic Tracks

18x13 = 18 lbs
18x12 = 17.5 lbs

Classic Street
18x12 = 18 lbs
18x10 = 16.5 lbs

The 17" my guess is under 17 lbs each.

Dont forget to add the tire wt in too.

CCW Classic street 18x12 with Mich PS 18x335/30 = 51 lbs



CCW Classic Track 18x13 with Good Year G19 = 39 lbs

davidfarmer

it is hard to beat the 10.5" Speedlines. I just pain mine black so I don't have to clean them.


btw, wheels weight is very imporatant, but the exactly calculations aren't easy. Rotating engine weight is the most important (that's why I run aluminum damper and 5.5" clutches), then wheels weight, then unsprung weight, then fixed weight. The faster an item rotates or moves, the more impact it has on performance.

The term you need to know is moment-of-inertia. It is an objects RESISTANCE to change of rotation . Since the mass of wheels is centered around the center of the wheel, the scales alone don't tell the entire story. If the hub is heavy and the rim light, the M-O-M might not be too bad, however if the hub light and the rim section is heavy, it could be a very high M-O-M.

You can build a hanging jig to measure approximate M-O-M, but unless you are really hardcore, I think you should just buy the wheels you like, especially for HPDE.

jwt1603

CCW's are very light and high quality but you pay for it. I couldn't afford them so I compromised and went with the Speedlines. It made a huge difference just in the way the steering felt. Car feels much easier to drive, the turn in response is great.

I was running cheap ZR-1 knockoffs and lost just shy of 10 pounds per corner going with the Speedlines so it was very noticeable.

As they say though...your results may vary.

95jersey

I use replicas on the street and OEM's at the track. I haven't weight the replica's, but they are noticeably heavier. I felt an IMMEDIATE difference in handling vs the lighter OEM wheels. I would stay away from replica's on the track based on strenght and weight.

RX7 KLR

In a test we did for SportsCar magazine we found that on a 2800lb car that puts 182hp to the wheels, going from a 44lb wheel/tire combo to a 39lb setup was worth 2 tenths of a second on a 45 sec course.

Taking 5lbs off a heavier setup on a car with WAY more power will likely make less of a difference.

However, if you NEED that tenth or so go for it.

0RAAMaudio

45 second course sounds like an autocross course, if that is the case there will be a pretty significant difference with the higher velocities, brake application, cornering speeds, etc..... on a road course.

As mentioned earlier the location of the weight, further out is far more dramatic in effect that closer to the hub.

I have no doubt in your test results but venture to say they may not cover the full spectrum of this discussion.

Just pointing out some observations, always a great deal of variables involved, other tests may show bigger differences.

(I just though of this, higher horsepower car, stickier tires, likely to be doing all things to a higher level even on the same course.)

Rick

RX7 KLR

For our test we were on an autox type course, top speeds in the 70's, both test were done on new Kumho V710s of the same size, and the wheels were the same size and offset (only the weight was different). We also had a data system in the car, but the .2 difference was so small we could not find it in the data even after 20+ runs.

We also did this same test back to back with the Bridgestone RE-01R, and could find no time difference at all. The fact that the we could spin the street tires on corner exit, and the ABS could overpower the tires under braking, meant we could not squeeze out that last few tenths.

No doubt higher speeds could change things... But imho there are a lot more gains to be had in other spots. Like in this case, rather than worrying about a few lbs of wheel weight buy some R compound tires, they are worth WAY more time.

0RAAMaudio

I have had one heck of a hectic week and must appologize as my post sounded allot more agresive than meant and certainly does not match my nature very well.

I am wondering if the skill of the driver being high enough can actually smooth the results instead of show them wider than what you found. Normally you would expect the opposite but a very intuitive driver can adapt very quickly and make adjustments, possibly without even realizing it at all.

You are or course absolutely right about the compound, I have quite a bit of time on RE-01 and V710s as well as many others. I have not ran on anything newer than the RE-01 on a "street tire" yet but up to them never liked a tire better. Fast, forgiving, good warning and feedback, great wear, etc......But, never going to be as fast as the 710's of course.

I read the test in Sportscar Mag, I get all the best mags and enjoy much of what is published in that one and GRM the most

Rick

RX7 KLR

I did not take it as harsh at all. I was just trying to fill in some of the gaps in my information.

Our unofficial-official SportsCar test driver is a bit of a hack, only a three time Solo National Champion ... But there is hope for him, he is off to try his first National RallyCross this weekend, and should have a Club Racing license by this time next month.

Bottom line for me, always spend the money on better tires before lighter wheels.

Come on Blu..... Just take a little taste of the R tire crack pipe, it wont hurt you, everyone is doing it.