cool, thanks for the info.dB said:Try googling "mechanical speedometer calibration". There are gear reductions/overdrives you can buy from speedo shops, but you have to know the error first...and there are no adjustable ones that I know of. Or you can take it to one of said shops and have it calibrated. But again you'd have to have it re-calibrated if you changed tires sizes or gear ratios (in the case of gearbox driven speedos).