does anyone know if a 255 45 18 tire will fit on the stock Rays engineering rims that the track model comes with. the stock tires that are on there now are 245 45 18. thanks

 

Go to Tirerack.com and see what rim size is recommended for the tire want to install.

 

Yes they will, but they will be slightly larger in diameter than the 245s.

section width (in mm) * profile * 2 / 2540 (mm per inch * 100) + wheel diameter = tire diameter

245 * 45 * 2 / 2540 + 18 = 26.68
255 * 45 * 2 / 2540 + 18 = 27.03 (approximately 3/8 inch taller)
275 * 40 * 2 / 2540 + 18 = 26.66

You can also determine what the "ideal" profile for a tire size would be:

(tire diameter - wheel diameter) * 2540 / (2 * section width (in mm)) = profile

(26.68 - 18) * 2540 / (2 * 255) = 43.23
(26.68 - 18) * 2540 / (2 * 275) = 40.09

This calculation doesn't take into account cantilevering of the sidewall, but that calculation is a bit more complex, requiring knowing where the section width is measured and whether the bead is on the outside edge of the sidewall, or on the inside edge.

 

You can go as wide as 265's on the rear and 245's on the front. You should go with 40's for both though.

 

thanks for the info, I just bought a pair of michelin pilots for $40 with 75% life left on them.