It appears all new Rykers have ONLY 16 inch wheels ....... So I checked what the Tire Rack has and was surprised to find quite a few in 205/45-16 ...... Vredestein Q-5 has a 205/50-15 for Rallye model ..... only one front tire ( @ 175/45-16 that's 30mm or 1.25 inches wider than stock ) that probably won't fit without mods to the fender and or bracket ........... Did I imagine that the 600 Ryker had 15 inch wheels ???? ............... thanks .... Mike