Sebring27

Hi,
I am considering running 18's all round on my C5 Z06. I am presently running 275/40/17 on the Front and 315/30/18 on the rear NT-01.

Any suggestions for the best set up for track days on square, 18's all round? Presents brakes, DBA4000 rotors, stock calipers, Pads, Carbotech XP10 front XP8 back. Track, Chuckwalla CA ( not too hard on barkes like Sebring)

I will be driving to the track so slicks out of the question.
Your comments would be appreciated.

Many thanks !

RaleighSS

While you can run larger ... I have been running 295 35 18 on all 4 corners without issues. I have not verified but did hear of front rubbing with other sizes and just decided to go with the 295 combo... + scrubs are easy to find.

Sebring27

Hi Thanks for your reply. Not sure if it is a dumb question or not but how does it differ in handling having the same tire sizes all round? I am presuming in your case you believe it superior to the 265 295 stock set up?
Thanks !

mountainbiker2

315/30/18 on all 4 corners, with stock rear C5 Z06 rims. Pick your tire of choice.

Steve A.

moespeeds

If you want you could run slicks. I drove my car home 400+ miles on slicks, and was driving it the 50 miles to the track until I got a trailer. I've also driven it in the rain and freezing cold on them, wasn't a problem. Continental takeoffs.

RDnomorecobra

General concensus is that running square takes out some of the inherent understeer by adding more front grip, therefore actually making it more neutral.

yakisoba

I am running 17" in front and rear. The reason is unsprung weight and stock brakes. If the car had big brakes, it would run on 18" wheels. 315 wide in back, 275-295 in front.

sleeperstyle

a 295/35/18 square setup would be ideal for me, but very few offer the 295-18 size... nto5 but i would rather something a little stickier.. 305/ 35/18 it is... everybody makes that size.. wonder how bad they will rub in the front.

ZedO6

I'm running a C5Z with OE 18" speedlines with Nitto 555RII's 285/35ZR18
s on all 4 corners without issue. Never rubs my Quantum brake ducts and with T1 bars and a track alignment, the car is balanced and very fast. Ideally you can run a larger section tire on all four corners, but I wanted to try the 555RII's and 305's were going to hit in front.

The ability to equalize tire wear by rotating tires from side to side (swapping tires on the rims when going side to side) for me is a huge advantage to a square setup. Unless you have gobs of TQ beyond stock, you really don't need to run bigger tires in the rear. The handling can easily be tuned with alignment, tire pressure and if you can adjust them, sway bars.

crimlwC6

I run 315 with NT01s square on 17 x11 c4 gs wheels. I even have a video of running at chuckwalla if you're interested. My car is a 99 FRC with Pfadt JOC sway bars and Pfadt old school inverted shocks. My car is track only and is 300 lbs or so lighter so it isn't apples to apples. Understeer is not an issue; oversteer can be
I've also ran 295/305 on c5 rears all around. The nt01s stick out well past the front fender.

crimlwC6

iirc nitto is now making 305 x 18. That might be your best option. You could order 4 and if you prefer having the 315 in the rear then you end up with 4 front tires.

charger21

I run 315/30-18 R888's all the way around with no issues.

RaleighSS

I have had no problems with with handling, been up to 160 and felt ok at speed ...

Sebring27

I would like to see your video, that would be great!

ktlocklear

315/30/18's squared here as well with no issues........

Sebring27

Hi ,
Great Pictures ! Thanks ! Question, you have no diffulties with rubbing when turning front at full lock? Sorry just wanted to make absolutely sure.

ktlocklear

Thanks!
Zero rub issues front/ rear. I do have a track alignment..so not sure if that would make a difference in not rubbing. It's got like -2.9 camber in the front

JeremyGSU

Interesting. With my 285's if I turn the wheel too much they rub my brake kit pretty bad. But I guess at the track you really aren't turning the wheel full lock so it shouldn't be an issue. I may go to 305's squared after reading this.

ktlocklear

yeah, not sure what to tell you....315/30 was the recommended tire size by MTI and Speed South....and seems to be the size of choice at the tracks around me by C5 owners. Again, zero rubbing issues....I've done 4 weekends with them now too. Stock brakes/ ducts, so maybe that's what the difference is if you're running aftermarket ducts?

Sebring27

Many thanks - Much appreciated - the grip must be phenomenal !