tire sizing question

[07audi4]

Im looking to purchase some new tires for my staggered setup. The wheels I have are 19" x 8.5" in the front and 19" x 9.5" in the rear. Up front I am going to run a 225/35/19 and in the rear I was wondering if I could run a 245/35/19? Previously there was a 255/30/19 on the rear...but there isn't much of a selection in that size. Can anyone help me out?

Chris


also...would the size of the sidewall look the same? (255/30 compared to 245/35?) basically I am going a little narrower but want the sidewall to look about the same.

[JD3]

best thing to do here is learn how to measure tire sizes yourself, believe me, it will make your life easier. Also, if you've got Quattro you better be careful, you don't want to run two different heights or circumfrances on your front and back. Think about it, they're rolling together. One wheel/tire setup can't be bigger than the other.
Here's how to determine sidewall height.
Let's use a tire sized 255/30/19. 255 is the width, in mm, of the tire. The 30 is what's called the aspect ratio. It's a percentage of the tire width and it determines the sidewall height. So you would take 255x.30 to determine the width of the sidewall in mm. In this case it's 76.5mm thick. 245/35 would be 245x.35 or 85.75mm thick. So 255/30 woudl be closer to your front tire height.
Also remember that it's only one sidewall, so to figure out the overall height of your wheels and tires you would take the 19" for the wheel, and multiply the sidewall height by 2.
Also, fyi, 25.4mm equals 1 inch.

[ADG05]

This should answer your question:

http://www.1010tires.com/tiresizecalculator.asp

[audimeister]

If you have quattro, and must have the staggered look, use the same size tire front and rear. Different circumference tires on different axles will cause problems with your center differential sooner or later.

Also, wider tires on the rear will cause the car to understeer even worse than stock.

[nramsey]

If you have quattro, and must have the staggered look, use the same size tire front and rear. Different circumference tires on different axles will cause problems with your center differential sooner or later.

Also, wider tires on the rear will cause the car to understeer even worse than stock.

^ this