Having had similar experience to PJC with my S1's speedo I resorted to a hairdrier to get the LCD screen working again (typical Morgan in the winter experience). Afterwards found my speedo was overreading. I have today after reading posts from 10 years ago recalibrated my speedo which at 60 was reading 48 (now shows 58 when my Google Maps on my phone shows 60). Originally posted by Philippo "Basically I measured the car speedo indicated speed against a couple of satnav devices. Then I entered into the speedo calibration mode, done by holding done odometer reset button then turning ignition on. Basically I then increased the speedo pulse number by close to the percentage of the over read. After a bit of trial and error I arrived at a speedo that reads roughly 1% fast, as opposed to 10% before. The final number of pulses can be + or - a bit since you're looking at a high number."
I have set mine at 46000 pulses which seems to work fine now so great result and demonstrates some really good advice on here.

In order to avoid breaking speed limits, do we not require the speedo to read higher than actual speed? In the case mentioned above, when google maps show 60, you really need the speedo to be 60+. Having said that, you also go on to say you have set it up with speedo reading fast, so I am a bit confused!

Legally a speedo should read between 0% and 10% over, not under (so you’re never going faster than you think you are).

Got above wrong way round, for clarity when speedo says 60 google maps say 58 (wouldn't make sense to set it up the other way round