Marky82

I have Enkei Winns and my question is can i put 275/45/17 instead of 275/40/17? My car is low with the ground effects and I want to get rid of some of the wheel well gap, since this will raise my height by an inch i was planning on then lowering it an inch. How much would this affect my speedo? One more question I need to get the rear tires replaced ASAP can I put 275/45/17's on the rear and keep the fronts 275/40/17 until they need to be replaced. I don't know much about tires so any info is helpful, thanks.



Mark

White30th

A 45 series tire on 17's will do 2 things. One, it will make the sidewall taller, making your wheels look smaller, plus giving the tires more chance of rubbing. Two, the taller diameter of the tire will throw your speedo off, by how much I am not sure. You *can* keep the tires on the front while replacing the back, but it would look kinda funny. IMO if you want to get rid of the wheel gap, get coil-overs.

Injuneer

The first question would be "where do you plan to buy 275/45's?".... Tire Rack does not list that size. If you could find them:

275/40-17 = 25.66" diameter = "stock"

275/45-17 = 26.74" diameter

The increased diameter would only raise the body up by 1/2 of the increase, or a shade over 1/2" (0.54"). And the speedo error would be an indicated speed 4.3% slower than actual speed, or indicating 57.4mph at an actual 60mph. Correction is easy.

Of course, putting larger diameter tires on the car has the same affect as going to a numerically lower rear axle ratio, so if you had an A4 with 3.23's, it would be like swapping in 3.10 gears (if they existed). And, increasing the diameter of the tire also increases the polar moment of inertia of the wheel/tire combo, with robs a little more HP when you accelerate..... .