Tire sizes

[Nuocmam]

Hey i just got 18s for my 528i but i need new tires.
tirerack.com said to go with 245/40/18
but will 245/45/18 be ok? i found a great deal on these tires. would a +5 make that much of a difference.
any help is aprreciated.

[HBpredhunter]

45 is the percent of profile compared to the width.

basically, 45 series is taller than a 40, but not by too much.

it should work out on a big 5 series.

[shadowkaya]

The main thing to assure is that your overall diameter isn't too different from the current wheel size otherwise you may need to adjust your speedometer. The 245/45 have about a 1" greater diameter than the 245/40 (about a 3.5% increase), which will throw your speedometer off by about 2mph at 60mph. Probably not a big deal. I've read that a greater than 3% increase in diameter size can affect the braking system but I'm not sure of the validity of this claim. Maybe someone else know more on that aspect. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

[Jim@tirerack]

I would not do it. The 245/45R18 is a full inch taller. It will throw off the speedometer, odometer and the gear ratio.

[98M3_4]

+1, stick with 40 series. Also possible clearance probs in the rear, especially if car is aftermarket lowered