tyre sizes

[smurf]

i have a new pair of front tyres ( p zeros ) but they are 255/35/19 not original size of 235/35/19 will these be ok to fit. thanks smurf

[SDR8]

According to an older post:
R8 Fitment info
"R8 Fitment info
5-112, 57.1 centerbore.

Front: 19x8.5 42et w/ 235/35-19 91Y. 8.5 Width can use 32-51 offsets. 9.0 Width could use 38-45 offsets. 255 would be max rec'd front width.

Rear 19x11.0 50et w/ 295/30-19 100Y. 10.5 Width can use 34-65 offsets. 11.0 --> 40-64 offset, and 11.5 --> 46-57 offset. 325 would be max tire width.

***Brakes are the hardest we have ever measured. The front caliper sticks out 44mm, and the rear sticks out 53mm."

It sounds like they would fit, but I am not sure how it will effect the diameter, which effects the revs compared to the rear. This is an all wheel drive car. Will things still work fine? Will it cause some form of binding or extra friction? Where does the speedometer get its reading from, transmission that mainly feeds the rear wheels? Perhaps going to a bit larger rear tire at the same time would help. I know the car comes with two different rear tire sizes stock (295 or 305), so some change seems ok.

[harrison]

Since you remained the same profile/diameter wheel/tire,: you are perfect. How do you like them??? It's ALL about the MIDDLE number on tire sizes.Stay with Audis recommended profiles untill you get approval for other sizes !!! Maybe you could dynamite the front differential with uneven profiles.MAYBE,

[911/Q45]

When the first # changes, so does the diameter. The profile is a % of the width.

[SDR8]

Just some quick stats on the size differences.
..................................235/35 R-19..........255/35 R-19...........Difference
Totals are in inches
Sidewall Height.................3.24......................3 .51.....................0.27
Section Width..................9.25.....................10 .04.....................0.79
Overall Dia.....................25.48..................... 26.03.....................0.55
Circumference................80.04................ .....81.77.....................1.73
Revs per Mile................791.64...................774.8 8..................-16.76

Miles/Hour (just pretending speed is based off front tires, if the gauge reads 65, your actual speed would be the following)
Speed ..........................65.0.................... ..66.41



As I posted above, I am not sure how this affects the Quarto system. You might want to ask someone at the service department of your dealership about it.