MTBSully

My 08 z06 currently has a 20" 360 forged wheel setup on it with 345 nittos. Not super happy with the nittos and the tires have to be super warm to have a chance of hooking in second. Won't even bother going to the track with them. Looking to pick up a drag setup and I think i've decided on 17x10" rears and 17x4.5 dark stars. I will likely run a M&H front runner, but am lost on the rears. Car makes ~600rwhp. 26" slick? 28" slick? Drag radial? Need some advice here boys!

Thanks

MTBSully

Anyone?

SoSlow1

Put a 325/45/17 M&H drag radial on and call it a day. Proven over and over one of the best DR's available. Going to run the Quick 30 this Saturday night at Royal Purple with that same tire.

rpmextra

i say 315-35R17 hoosier dr2, i have been a low as 1.40 on my 60ft with them and a good friend of mine runs low 1.3x all day long same tire

BIGMAC

I would like to run this tire but there are many reports that it's diameter (listed as 28" but I am told the actual measure when mounted is less) is out of the front/rear diameter difference tolerance allowed by the TC/AH system. The reports say this could cause unwanted application of AH and/or putting the car in limp mode. I have been unsuccessful in determining exactly what the tolerance is. Some say the magic ratio is 1.04 rear/front but the Nitto NT05 345/30/19 on the car now are 1.06 with no problems. I have a heavily modded 2012 GS ready for track testing. I know the Nittos on the car now are useless at the track with 750 RWHP but I don't want to invest in a 17" wheel/tire combo that has a 50/50 chance of causing big TC/AH issues.

I would appreciate feedback from the Fourm,

Thanks in advance.

BIGMAC

rpmextra

The issue with using a 28" with your Z06 gears 2.66 1st gear and 3.42 rear end mean you need all the gear you can get. 28" will hurt that a bit.

BIGMAC

Actually I have an A6 built by Century of Houston. I wanted to go with 3:10 rear gears due to the steep 1-2 gears in the A6 but my builder talked me into a C6 Z06 3.42 rear assembly. I am looking for less gear so the taller tire is what I want!

BIGMAC

rpmextra

Then there you have it lol.

SoSlow1

Hey BIGMAC there is 3 C6's in our area running the M&H 185/55/17 front 325/45/17 rear combo and none of us have TC/AH problems. My car has only gone into limp home 1 time and that was because of a shift issue with the 2-3 shift on my stock A6. The 2005 has 3.42 gears and mine (2009) and the other(2009) has 2.56 gears. Like I said earlier we are going to the Quick 30 track rental tonight in Houston with the other A6 car running the 325/45/17 tire and I can post up tomorrow how the car runs. I'm going to bring my car but don't know at this point if I'm going to mount my drag pac or just have some fun with my street tires.

CI GS

Like BIGMAC I have a GS with an A6 and the 3.42 Z06 diff, so I need all the tire diameter I can get on the rear.
I'm running M&H Racemasters: 185/55/17 fronts and 325/45/17s on 17x5" and 17x11" Weld RT-S wheels and have had no problems whatsoever with AH activation, which I was very concerned about as well.
FYI: The 185/55s have a measured dia. of ~25.5" and the 325/45s are ~27.5" mounted and inflated to 35psi and 18psi respectively (which my car handles decently with on the street). I'm not sure what the front/rear tolerance ratio is, but these tires work for me.
BTW: I always run my car in "Comp" mode, but I'm not sure if that makes any difference with the AH system?

SoSlow1

Good point I forgot to mention we do turn the traction control and the active handling nannies off before each pass..

GARY2004Z06

For a manual trans, you would better be served by bias ply tire rather than a radial. If you can locate a set of MT 26x11.50x17 ET Streets, they would be a great tire. They are no longer made but can produce consistent 1.4s with practice on a decently prepped track.

CI GS

A bias-ply tire will absorb the initial shock of a manual setup better and so will probably ET better, depending on power output. The only caveat would be, of course, that you will need to run bias-ply front runners with them, otherwise it will get very squirrelly on the top end. Ask me how I know...

MTBSully

Are all bias ply tires tubed? Can a 28" tire fit under our fenders?

GARY2004Z06

Not all are tubed.
Here are Hoosier 28x11.50-16LT QUICK TIME PRO D.O.T.s than we ran at an event and rental at MIR.

MTBSully

Damn that is moving out! What is done to your car? Stock trans and gearing? What'd you have to do to get the 16" wheels to clear the z06 brakes?

GARY2004Z06

Thanks.
Just bolt-ons.
RPS Clutch, 4.10s, CAI, Headers, Ported TB, Ported FAST 102
TR 6060 with stock ratios
Brakes were swapped over to C5Z brakes and knuckles modified slightly to accommodate the 16" Bogarts.

MTBSully

Think im gonna go with the 315/35/17 hoosiers. Can I run a bias ply front runner or am I better off with a radial? Seems the only skinny radial available is the M&H

rpmextra

Yeah you can run a bias ply up front with a radial in back I do myself.
M&H has either. The radial might be better if you drive further distances with them on.

HOXXOH

Assuming you only intend to run these tires at the track and not on the street, the first thing to check is what your RPM will be at the finish line. Here's a calculator to help.
http://www.wallaceracing.com/Calculators.htm
IIRC a stock geared Z06 with 315's will run out of RPM in 3rd shortly after the 1000' mark. You want to be just short of the rev-limiter at the stripe, so it takes a taller tire in 3rd or a different rear gear to use 4th.

If you're not too far from the track or you change wheels at the track, the M&H bias skinny is the lighter tire to use. Since the main reason to run skinnys is to reduce weight, you should consider swapping brakes from the J56 to J9L base brakes and save several more pounds.