24hr Z06

Im going to start participating in HDPE events and have two sets of wheels I can use.. The tires on both sets of wheels need to be replaced so the question is which wheel should I get tires for and run on the track..

I have stock C5 Z06 wheels front - 17 x 8.5, rear - 18 x 10.5 and CCW Classics fronts are 18 x 10 and rears are 18 x 12...

I have never tracked a car, but did about 10 or so events on a motorcycle..

Ill be driving the car to and from events and I dont want to be changing tires... What do you guys think I should go with??

Thanks,

GettReal

When I was running Stock C5Z sizes I ran with Nitto 555RII's in

275/40/17 (and the front is 9.5 not 8.5)
305/35/18

GREAT dual use tire that is sticky but you can drive to the track on them and they last long.

Wait till you build up track experience then throw some hoosiers on the CCWs.

24hr Z06

i was thinking about running the R2's, good to hear....

hamdog

RA1's, R888's. Both sets of are great for racing. Strong and light. With the CCW's you more room for wider rubber though.

L98Terror

That's what I did, then went to NT01s. I would choose either RII are better in the rain if you get caught on your way home

24hr Z06

So..

With stock wheels go with the nitto R2s..
front - 275/40/17
rear - 305/35/18

CCWs, go with Nitto NT-01s
front - 275/35ZR-18
rear - 315/30ZR-18 98W BLK

Ive heard great things about the Toyos but they're pretty pricey mounted on the CCWs..
R888s - $560fronts, $670rears
RA1s - $638fronts, $770rears

gkmccready

Note that 315/30r18 is 25.4in tall and the 275/35r18 is 25.6in tall, so don't expect your Active Handling to be happy if you use those sizes. This is one of the reasons I'm on R888s 275/35r18+305/35r18 ... since I drive them daily and want something that works with the nannies in case the wife grabs the car...

24hr Z06

R2s are 25.67-front, 26.3-rear

at what point does it become an issue with AH?

zcobra1

I second that- this is what I run- excellent compromise- tire is still forgiving for the not real experienced...
Also the 17/18 RII's are alot cheaper than the 18's all around- like under $900 a set last time....

gkmccready

Um, according to the Nitto website 26.3 is for the 305/35r18 -- you mentioned using a 315/30r18? I agree the 305/35r18 combined with a 275/40r17 or 275/35r18 works well.

I'm not sure anybody knows the official cut-off for what affects AH, but everybody seems to agree you need a bigger rear and the closer you get to the stock difference the better if you're going to use AH.

Bill Dearborn

TC and AH activation are two separate things and the tire diameters have a different effect on them.

As long as the rear tire is larger you shouldn't have any problems with TC other than earlier activation if the wheels spin. Active Handling is happy with equal diameters front and rear. Some cars don't have any TC issues with equal diameters either. However, you never know whether your TC will have an issue until you try it.

AH may not have any issues if the rear wheels are smaller in diameter as it doesn't use wheel speeds to determine whether or not the car is yawing sufficiently to go in the direction the driver is turning the steering wheel. When AH applies the brake to an individual front or rear wheel it uses the wheel speed sensor at that wheel to determine how close to lock up the wheel is.

Bill

24hr Z06

youre right the 315s wouldnt be a good idea..

I did a quick look at whats available and setup a spreadsheet.. Toyo proxes are definitely the closest matched for the CCWs, RA1s would also work well on the stock wheels..

darguy

Hey Gang,

I was going to post a nearly identical thread with similar questions, mind if I toss some queries in?

I've got a '99 FRC DD that I'm also setting up for Track Days (maybe 6 a year), plus a bit of auto-x. Our local track is not super fast, but has plenty of corners. I'm looking at a set of C5 Z06 wheels to replace the street worn thinspokes, which have Toyo Proxes T1R's on them - which are great in the rain for a DD, which is particularly important around here.

For std Z sizes I've found the T1R's at 1010tires, Bridgestone Potenza RE760 Sports and Firestone Firehawk Wide-Ovals at Tire Rack (F1 Supercars too, but the wet numbers don't look very good by comparison), and Michelin Pilot Sport PS2s at Discount Tire. I'll need to take a trip into Wash to source the tires, so have been looking at the major vendors there.

By the numbers the Potenzas come out at a pretty good bargain ($766 plus taxes, etc). And, the PS2s are highly reccommended but are pretty pricey ($1454 plus taxes, etc). Should I also be looking at the Nitto 555RIIs for a DD and Track Day car on stock Z rims? Any suggested vendors?

Don't mean to hijack the thread, but didn't think it warranted a duplicate.

24hr Z06

I got some responses from a few more people and they also recommended the nitto R2s..

sticky, close to stock tire diameters and decently priced... i have my answer..

thanks for all the help guys, very helpful.. looking forward to getting on the track..

geerookie

My understanding is that no codes will be set as long as the EBTCM doesn't see a wheel speed variation of more than 14 Km/h (9 mph) for 2.5 seconds. You would have to have a very large wheel size difference to create this situation.
Obviously you need to be careful and not get to close to the 9mph limit as when you have normal wheel speed differences in a corner you would set the code falsely.
When the codes are set it disables ABS/TCS/AH.
They will automatically clear after 50 ignition cycles with no more codes set. ABS/TCS/AH will re-enable after the condition clears.

Just as an FYI, ABS/TCS?AH are all handled by the EBTCM. There are many codes from the wheel sensors, steering sensor, yaw sensor, lateral acceleration sensor that will disable TCS/AH but not effect ABS. If your wheel speed sensors are working properly I think there are only 4 codes that will disable everything. C1225, C1226, C1227, C1228. These are more than a 9mph difference for 2.5 secs from any sensor.

24hr Z06

mph difference with the Nitto 275/40-17 R2's in front..
at 160 - 1.96mph, 1.22%

Nitto 305/35-18 R2s in the rear at 160.. 1.67mph, 1.04%

geerookie

Hope to see you at the track. I run with NASA/PDA NorthEast.
Limerock 3/27...might need snow tires
NJMP 4/16 - 4/18

stevensa

Im currently looking for fresh tires myself. A set of 555RII's is about 100 more than a set of NT-05's. This is probably a simple answer, but are the R2's significantly better performing than the NT-05's for the extra cost?

geerookie

The R2's are a little stickier and may make a 1/10 or 2 difference in lap times depending on the driver. The NT-05's last much longer! If it is for track day fun and driving there and back then the NT-05's will be a much better choice IMO.

I run NT-05's 285/35-18 all around and ran 1.02's and 03's at Limerock all day long. C5 coupe, 3400# w/driver, stock LS1 with 111k miles, not even headers.

AlwaysInBoost

I would use the oem z06 wheels first with a decent street tire so you can get a feel for the car on track. something like the nitto nt05 would be a good choice or anything with around a 200 utqg rating.
after you wear them out if you want something faster I'd go with the RII. they're an excellent dual purpose tire.

if thats still not fast enough your only other option is to get a tire trailer and slap some r-comps on those ccw's. but then you would be swapping tires at an event, which you didn't want to do.
in order to keep you from having to swap tires how about I take those ccw's off your hand.