New here and to Audis. I joined another form and have posted this question for about a week with no response. Form the threads I have read through I think this will work but wold like to verify before ordering tires.

I have a 08 A3. Just bought some 18x8 with 45offset. Will eventually be lowered 2" max. Would like to run 235/40/18. Looks like that is only about 1/2" wider the stock. Opinions if they will fit no problem?

Thanks in advance.

 

I put similar wheels and tires (though they were 225/45/18) and they fit fine but lowering changes a lot of things, so I can't really answer specifically how it'll work.

FWIW, the first number (i.e. 235) is the width of the tire tread in millimeters (1" equals 25.4mm).
The second number (i.e. 40) is the percentage of the sidewall height to tire width (in this case, 235mm x 0.40, or 94mm / 3.7")
The third number is the rim diameter. To calculate the tire's outside diameter just add the third number to two times the sidewall height (in this case, 18" + 3.7" +3.7", since there are two sidewalls in the total height).

If you have narrower tires on your rims, and want to see if wider ones will fit, just measure the clearance and then calculate if there's room for half of the increased width (and/or height, if that's changing as well). Again, this can be difficult because the arc of the travel of the tires in the wheelwells depends on the suspension geometry. You might want to try a jack under the end of the control arm near the ball joint to raise the tire as much as possible to get the tire up inside the fender lip, so you can get a good measurement.

 

Its not going to be slammed. Just enough take the fender gap out. Tires you listed are stock width. Ones Im looking at are 1/2 wider. By all the stuff I have searched I think they would fit no problem.

With all of these cars out their i'm sure someone has ran this or tried. Just trying to get someone to chime in.

Worse case I have the used tire store mount up a cheap tire and try out.

 

Or you can spend a couple minutes and measure / calculate to figure it out, too (sounds a lot easier to me, but YMMV). Keep in mind that half of the increase in tire width will be on the outside, and half on the inside, and it wouldn't hurt to do a full-lock on the steering both directions just to make sure you won't end up with interference between the tire and wheel well liner.

 

Thanks for the info, I will keep it in my mind.

 

See my threads Ground Control Coilover Conversion under Suspension and A3 Wheel/Tire Fitment under Wheels and Tires.

 

OK, thank you. I will check it.