Most mods do,but cheaper bikes have 20" rear wheels,my da bomb school had one so i had to get a 20" sticky fingers tyre,after trying to fit a creepy crawler 19" and finding out it didn't fit...DOH! Also onza t-vee's have 20" rear wheels,you can tell if a bike has a 19" rear wheel or not because the tyre will look really big and fat/beefy. zoo baby!