Bugger. If only I'd seen that two days ago! The "calibration" trick of reading tacho readings before and after was a good one. I just basically winged it, after I realised how easily the pin spins around messing you up - I went around the block then turned ignition off, to try to get a zero position. Placed the needle on speedo, did another block, "feeling" where gear changes were and what 40, 60 felt and sounded like. Re adjusted, did the block again, etc til I was pretty happy with it. Just went on a long run today, checking my speedo against traffic at diff speed limits, and I seem to be pretty spot on. Now I'm just on the lookout for one of those portable speed check signs they park on suburban streets to tell you you're going too fast. Then I'll have a great time going round and round at diff speeds! Thanks for your post though, good step by step.