That 195 width is going to be too narrow for the rear rim on a Spyder & too wide for the OE front rims too! (I dunno about the Rykers, what rim widths do they run?) Some 205's might be a tad hard to get onto that rear rim as well, so you will need to check the actual physical dimensions before committing, but you can probably look at tires between 205 and 225 in 50 to 60-65 profiles; bearing in mind that the stock tires are 225/50's & if you go down one size in width you will usually be fairly safe to go up one size in profile & still remain fairly close to the same rolling diameter. :thumbup:
That means you could try 215/60's or 205/65's & they should be close; but once again, you'll need to check the ACTUAL dimensions not the nominal tire sizes to know for sure! For example, I think it's the General Altimax 205/55R15's that are almost identical in rolling diameter to the OE Kenda 225/50R15's.