In Reply to: Tire size Question posted by James on December 09, 1999 at 12:31:43:
The 225/55/16 definitely will allow for better handling than the 225/606/15 because there is less tire wall flex. And the 235/45/17 is absolutely better than the 16" for the same reason. I have actually driven my E39 528 with all three tire sizes so I can tell you this from my own personal experience. Of course with the 17" wheel you ideally want the sport suspension package as that is tuned to that size tire.
The tire make and model also make a real difference too.
If you are sensitive to road noise you will hear some more with the 17" wheel. However with the Dunlop SP2000 or the Continental ContiSportContact the noise level is not bad. But with the higher performance tires like the Toyo T1+ the E39 is quite amazing in terms of handling. However with a higher performance tire with a more rigid side wall like the Toyo T1+ the entire E39 will act like a big bass drum over bumps which I don't like at all. I haven't tried the new T1S but it probably has the same drawback.
: Whats the difference between running 225/60/15 and 225/55/16? except for less tire sidewall and more allow rim, does it actually improve handling? and if so how? because they are all 225's and I would think that sidewall of the tire does not matter in handling. how about 17 inch rims? 235? it's only 10mm wider, how much handling could that REALLY improve? I hear that the smallerthe sidewall is the better handling you get, but i don't believe it, I think that it has to do with the width of the tire.