SVT CONTOUR LOVE
CEG'er
i got 17s and the 45 profile gives a bit of a rough ride can i go to a 50?
Use either of the two frequently used tire sizing calculators - Tacoma site or Miata site. SoundQ is correct - dropping 10mm in cross section when increasing profile by a ration of 5.215/45/17 is the correct size for a 17" wheel. If you want a 50 series tire, you will need to go down to a 205 width to keep the same sidewall height and not make your speedometer totally useless. What is the point in that?
If your sidewalls are too stiff (like you have run flats or something) then just get different tires that are a little more luxury than performance oriented.