For my new build I am going to use a 26" front wheel, and a 20" rear wheel to archieve a "Chopper-Like" effect. Now, the part that really bothers me is; the frame is steel, and I am wondering if I use a 26" wheel in front and 20" in the back will it crack the frame while riding because the front is more elevated than the back? Originally it was this junk bike that I found and on rode, striped it and saved and refurbished the frame. Steel frames are strong so I dont know if putting a 20" wheel on the back would be much of a bad idea. Here are some pictures of the Primed Frame. What do you think?