just a note...ive run solid inner tubes on both tires on a bicycle but on my motorised bikes i only run them on the front...they do have a tendency to shift a little...and remember you must have a wheel size of 26 x 1.75....2.125 are to big for the tubes...other than that they are great...i just run good liniers and tape upthe spokes with gray tape and run torn proof inner tubes on the back..never had a flat yet...cross my fingers...good luck...Dennis