[silverforumsurf]

Total newb related to how tires work.

How much less side wall does the 19'' wheels tires have relative to the 18'' wheel tires? The stagged performance tires (mixed performance 309s) if that makes a difference.

[fedinand]

245/45/19 fronts and 275/40/19 in the rears vs 245/50/18 all around or 245/50/18 front and 275/45/18 rear. You are basically giving up some ride quality with the 19s, but they still ride very well - not harsh by any means. There will be a difference in ride quality going from 50 series of the 18s to 45 and 40 series of the 19s, but as stated earlier - the ride is not harsh with the 19s.

[Harplayr]

By going to a lower profile tire, will you notice any improvement in lateral stiffness in cornering or high crosswinds?

[silverforumsurf]

is there some type of calculation or rough % math I should be thinking about?

[Beyu]

Originally Posted by silverforumsurf

is there some type of calculation or rough % math I should be thinking about?

Here's a very nice guide for explaining what the numbers on tires mean. I believe the 18" wheels aren't staggered and only the 19" are.

http://www.tirerack.com/tires/tirete....jsp?techid=46

19" wheels sidewall:
245/45/19 front: 4.34 inches
275/40/19 rear: 4.33 inches

18" wheels sidewall:
245/50/18 all around: 4.83 inches

So usually the lower the middle number is the less sidewall the tires have.