rikhek

I've bought four 18" x 10.5" OEM Z06 wheels for road course use. Will be running R compound tires with 305's on the rear. Not sure if i'm better off running 275/285 fronts or 305's all the way around.

What are the advantages & disadvantages? Price is the same for the scrubs I'm buying.

Advice would be appreciated.

Rick

meldog21

I just put four 18x10.5's on with Nitto R2's, 285 fr, 305 rr. I haven't taken it to the track yet(Thunderhill 24 July), but my impressions from driving the back roads are that it added front end traction. I drove today for about an hour up and down Mt Hamiltion road. I only got a little push in one corner and I think that was due to my entry. The active handling was coming on a lot so although I wasn't fishtailing out of corners, the car thought I was tail happy. I'm going to change to the softer setting on my rear sway bars and see if that balances things out.

My guess is that 305's all around would give you even more front end grip, and you might have a problem with tire rub too.

Dog

AU N EGL

305s all around do give you better grip, and far better braking but limit your top end and are a big harder on very tight truns. Car may oversteer. 305s on front are good it your using 335 or 345 on the rear.

Oyishdog

I personally like a staggered setup and run a 275 front ~305ish (Hoosier rolex gt tire) rear...that setup gives me great feel for my car. unfortunately, the best way to decide is to try both and decide whats best for you.

Wicked Weasel

wouldn't 275 or 285 give you a quicker turn in, but less traction once in the turn?

Red Gump

I too have the 18x10.5 x4 track setup. in my last event (april viperdays here in sebring) I started with 265 front and 295 rears and had bad understeer and cooked the brakes.

a buddy let me borrow his 305x4 setup (THANK YOU WOOSCH!!!) and the car felt MUCH better and the brakes kept cool. I don't know if it was the added confidence of the setup but I dropped my time by :05.

if you wanted stagger I'd say 295 + 305 or 305 + 315 or 335 but I can't find 315's and 335's won't fit (to my knowledge anyway).

rikhek

Will 305's on the front rub my DRM ducts?

rikhek

At Hallett top end is not critical. There are two 2nd gear tight turns.

Is your advice to stagger or go 305's all around?

I don't have the option for larger than 305's based on wheel size.

Thanks.

Rick

Olitho

I like the way the car drives better with 305s all the way around than when I have 335s in the rear.

305s will likely rub your DRMs unless you put a collar on your steering rack to limit the turning radius slightly. Mine have holes in them from the 305s. They may also rub the top outer portion of your front fender slightly when you load up the suspension hard in turns. This has worn my fender slightly, but seemingly no harm to the many tires I have run as the rub is very slight in my case. My fender is rubbed away a bit in that area, but the look is not noticeable.

larryfs

I have a pair of RS04: 335 18" hoosiers . only used twice. $50 for the pair.

John Shiels

305's square would be my choice

AU N EGL

Rick

I would stager, 275 f and 305 r


275s will give you a tighter turn in.



yes the 305s will rub on the DRM ducts, but your not going to turn that tight on the track or at speed.

Red Gump

if they fit on 18x10.5's I'd take them. what were they on before?

larryfs

They were on the rear of a Z06 race car. You can still see the tread that Hoosiers come with. Hoosiers came with a very slight amount of tread, and after a few uses they look like slicks. So you'll see they have been used very very little. They are Hoosier RS03's, not 04 as I previously thought.

I have 17" AS04's for sale too. real cheap.

Olitho

10.5" rims are not big enough to properly accomodate 335s.