Speedo threads

[Alan]

I used original in the sense that I wanted the speedo that’s fitted to read correctly not to replace it with a bike speedo. The problem is it’s a belt driven system- that outputs 3360 turns per mile. The rather nice speedo head I have takes 2240tpm so it over reads somewhat. Options as I see it are new pulleys, a corrector box or just get better at mental arithmetic.