Tires for my 2006 E90 325i

My car had 225/40/18's on it all around. I replaced them with 235/40/18's all around and kept them all the same in order to rotate. If I go with a 255/35/18 on the rear would it be best to stay with a 235 or go back to the 225 up front?
By the way I also use spacers 20mm on the rear to add a staggered look even though they are not.

Is there any reason why I could not do 255/35/18 all around to rotate or will that negatively effect steering or braking etc.? It does not appear it would effect clearance just looking at the following. What do you think?

our Results:Start Over

Stock Tire - 225/40R18
Tire 1 - 235/40R18
Tire 2 - 255/35R18

Section Width: 8.85 in 225 mm
Section Width: 9.25 in 235 mm
Section Width: 10.03 in 255 mm

Overall Diameter: 25.08 in 637.03 mm
Overall Diameter: 25.40 in 645.16 mm
Overall Diameter: 25.02 in 635.50 mm

Sidewall Height: 3.54 in 89.916 mm
Sidewall Height: 3.70 in 93.98 mm
Sidewall Height: 3.51 in 89.154 mm

Radius: 12.54 in 318.51 mm
Radius: 12.70 in 322.58 mm
Radius: 12.51 in 317.75 mm

Circumference: 78.79 in 2001.2 mm
Circumference: 79.79 in 2026.6 mm
Circumference: 78.60 in 1996.4 mm

Revs per Mile: 829.3
Revs per Mile: 818.8
Revs per Mile: 831.3

Actual Speed: 60 mph 100 km/h
Speedometer1: 59.2 mph 98.7 km/h
Speedometer1: 60.1 mph 100. km/h

Either 225/4018 or 235/40R18 will go fine with 255/35R18 even though technically the 225/40R18 is a bit closer in overall diameter.

255/35R18 would require at least an 8.5" wide wheel (the factory front wheel is just 8" wide) and we have had some reports of rubbing up front with 255/35R18 on this car.


Tires http://www.tirerack.com/a.jsp?a=AB2&...ires/index.jsp