I know all speedos are out generally, but on my 3 door Cossy i have 205 - 55 - 15 tyres on the rear just as i got em at a good price, but even at 20mph my speedo shows nil, then from 20 upwards it kinda lags behind a bit lol, i just wondered if it was as simple as the tyres, and yes im on standard 205 - 50 - 15 fronts, cheers.