As mentioned in my introduction, I picked this trike up in Oct, 20" tires on the rear, 17" on the front. The forks, which are no longer made, are 59mm 8 over inverted chrome front end. I am thinking I could get a 21" wheel and hopefully miss the radiator but I would love a 23". Don't want to cut the frame to rake, hoping to find some raked tree's that will work w/ 59 mm forks. Last resort I can hope for a 21" that might fit.