With a wireless unit, I believe that moving the speed sensor and magnet to the rear wheel is not an option.The unit and sensor need to be in line and closer together. Even most wired units have a wire that is too short to mount on the rear wheel, unless it also has a cadence sensor that mounts on the crank. That kind of wiring is very susceptible to damage due to the length and locations of the wiring. For me, at this point, I have no need for a GPS unit. I do not want to track my routes, and I do not want to be tracked. I still have a flip phone that I carry with me, but usually have turned off when riding. A basic wireless computer is all I wish to have, and gives me the basic data that I use. Cateye Velo 9 wireless can be purchased for a bit more than $20, and it is very durable and gives accurate readings.