Blow out! Need recommendation.

[GoFastKindaGuy]

From the world of "better lucky than good," I experienced a right front tire blow out today. Thankfully, it occured during a low speed turn at a traffic light, a mile from my office and a half mile from my tire/wheel service provider -- so I had the stock 18x8.5 wheels and snow tires mounted.

Looking at my Kinesis 19x9s with SP9000s, the inside of both fronts were worn through from intermittent rubbing against the upper control arms. One can see the polished spots. Each of these tires had several separations between one and three inches long! Rears are perfect. Rubbing is not something I heard or felt in close to 18,000 miles (the balance of 9,000 miles are on the winter wheels and tires), but it has obviously been going on for some time. I did not notice damage last Fall when I swapped them out for Winter. Maybe it happened on my one track day this October. Damn, I feel lucky. Now I need a solution, if anyone can help.

The Kinesis are +35 mm offset vs +25 on the stock wheels. Therefore, the wheels stick out 5/8ths on the outside, but 1/8th less on the inside. My Dunlop S9000s are 255/35-19s, so the diameters are supposed to be identical to stock 255/40-18 tires and I have had no rubbing on the fender flairs. Will a 1/8 or 1/4 spacer on the front wheels solve the rubbing, or just move it from inside to the wheel flairs? Anybody else had experience with 19 Kinesis on an RS6? Help. I don't want to die.
:MTM:

[JAXRS6]

Originally posted by GoFastKindaGuy

The Kinesis are +35 mm offset vs +25 on the stock wheels.

Champion Motorsport told me the stock RS6 offset is 30.

[gjg]

I think stock 19" offset is 20, but I will pull the manual out to confirm.

gg

[gjg]

I'd use a spacer

[GoFastKindaGuy]

The US specification stock wheels are 9 spoke, 18" dia.
I was told these have +25mm offset back when I did this.

[Benman]

Originally posted by GoFastKindaGuy
From the world of "better lucky than good," I experienced a right front tire blow out today. Thankfully, it occured during a low speed turn at a traffic light, a mile from my office and a half mile from my tire/wheel service provider
That is lucky! Sorry to hear about that, blowouts suck.

I'd go with gjg's spacer suggestion.

Ben:addict:

[aussie rs6]

Hi GoFastKindaGuy,

sorry to hear about blowout. Very bad news, but very fortunate that happened at low speed.

the problem and result you experienced is exactly the reason as per earlier post that I decided not to run the michelin ps2 tyres on the front on the stock oem 19" euro spec rims as the kerb protector strip on the michelin ps2's was rubbing on both uprights on sharp turns. I had to go back to the oem continentals.

your experience justs shows how tight the clearance for stock oem 19 "wheels is on the beast.

All owners contemplating changing to aftermarket 19" wheels and even tyres, need to keep this in mind.

regards,
john

[GoFastKindaGuy]

Well, I've done a bunch of measuring -- no theory, horses mouth to count teeth. Here is what I have found:

Kinesis with Dunlop SP9000 255/35-19 vs 255/40-18 (unmounted):
1) maximum tire width... 10.25 in vs 10.00
2) tread width... 9.0 and 9.0
3) sidewall width (about 1/2 inch from OD)...9.5 and 9.5
4) Kinesis 19x9" offset is 22mm and backspacing is 151 mm.
5) Stock nine spoke 18x8.5" RS6 wheel offset is 35mm and back spacing is 155mm.
6) Minimum clearance between sidewall and suspension....0.38 in. vs 0.75 (this compared to 225/45-18 Dunlop Winter Sport M3).
With 0.13 spacer and 255/35-19s, 0.50 in. clearance.

So, it doesn't appear that the tire difference caused the rub -- the extra width is near the wheel, not where the rub is (about 1/2 from the OD).

It does not appear to be the wheel offset -- the back spacing is 4mm better than the stock wheels.

I cannot believe it is tire deflection under cornering -- it should be less with a 3.5 sidewall vs 4.0. Is my logic flawed somewhere? This is driving me nuts.:cry: