Going from a 45 to 55 series tire?

[Philly215]

I have a 2011 A4 Premium plus with no sports package so it has 17" wheels. I had H&R sport springs on the car but I had to put the stock springs back on because the roads where I live were just destroying the car. The gap is driving me crazy though and it makes the wheels and tires look really tiny compared to the car. I believe the car has 45 series tires on it but not positive, so I was thinking of going to a 55. Is this doable? Will it cause any issues like clearance problems, speedometer issues, rubbing, etc? I was also thinking of getting 18's with a 45 series tire and that would effectively accomplish the same thing.

[Skyler@Achtuning]

I don't think you'll be able to go over 1/2" larger in overall diameter without rubbing or speedo/abs issues. If you're trying to raise it up may be to use stock non-S-Line springs for the most ground clearance.

[TCHUN003]

What size are your tires right now?

[sdy101]

This website should be able to help answer most of your questions regarding the difference between tire sizes (overall diameter, sidewall height, speedometer changes, etc): http://www.1010tires.com/tiresizecalculator.asp

Rubbing/clearance will depend on wheel offset and other things that I am certainly no expert on.... but I'm sure others will jump in and can help with that!

[Philly215]

The tires are currently 245/45/17. I have some wheel spacers on as well. 15mm in the front and 20mm in the rear. Tire Rack has a few tires in a 245/50/17.

[Philly215]

I don't think you'll be able to go over 1/2" larger in overall diameter without rubbing or speedo/abs issues. If you're trying to raise it up may be to use stock non-S-Line springs for the most ground clearance.

Yea, I just had my OEM springs put back on today. It's a non sport or S-line model so it's the highest ride height you can get with an A4. I just want to get rid of some of the wheel gap and make the tires look more proportional to the car.

[Philly215]

This website should be able to help answer most of your questions regarding the difference between tire sizes (overall diameter, sidewall height, speedometer changes, etc): http://www.1010tires.com/tiresizecalculator.asp

Rubbing/clearance will depend on wheel offset and other things that I am certainly no expert on.... but I'm sure others will jump in and can help with that!

Great site, thanks. The speedometer doesn't look like it will be affected much so that wouldn't be a problem.

[equ]

Why do people think they can just change tire sizes? Will your spare work should you need it? Just stick to what the manufacturer says. Period.

245/45-17 has plenty of sidewall by modern standards. Avoid the potholes you can avoid. Lower the pressures, no more than 33psi all around when tires are cold but at room temperature. So if the car is parked outside, at 30F, you should have them at 31psi all around first thing in the morning.

[VMRWheels]

Great site, thanks. The speedometer doesn't look like it will be affected much so that wouldn't be a problem.

I'm not sure what you were reading, but going to a 245/55 is greater than 7% diameter difference from manufacturer's spec, which will throw your speedometer way off as well as possibly cause other problems. Stick with OEM tire sizing.

[Philly215]

I clearly don't think I can just change tire sizes, hence why I'm on here finding out.

[Philly215]

I'm not sure what you were reading, but going to a 245/55 is greater than 7% diameter difference from manufacturer's spec, which will throw your speedometer way off as well as possibly cause other problems. Stick with OEM tire sizing.

I posted earlier that I was looking at 50 series tires instead, and it's not too much different.

[dame drizzo]

I know you can fit 255/40 on the b8 without having any rubbing issues. As to change the tire to rim ratio to 50%, it doesn't seem like it's worth it. 45 is more than enough for the b8

[equ]

The only allowed higher profile is 225/50-17.