Speedo Correction

[slobbo]

I am running bigger tyres on my Syncro and as a result my speedo is reading 8% under what it should. I believe you can re-gear the speedo. Any ideas where I can get what I need?

[Aidan]

Rob you have to change the speedo drive output in the front diff, there's a lmit to what can be achieved as the drive cog which is fitted to the front pinionshaft is the limiting factor, you probably have an 8, so can only run 8/18, 8/19,8/20 or 8/21
what is the letter (if present) stamped under your code on the bottom of the diff (eg A) - that will tell us what you should have in there originally
factory set up is overreads speed by 10% and odo is correct, putting on bigger tyres normally brings speedo towards correct but then odo underreads, (eg I have 185R14C speedo drive fitted but run 205s so it's only 6% over on the speedo and with my weekend rubber on it's almost bang on, but obviously my mileage readings are always under) you have a big tyre size hike and probably the wrong speedo drive fitted already (not uncommon)
They aren't all available anymore and are £100 each now and no I don't have any good spare used ones for sale

[slobbo]

Looks like it is plan b which is make my own dash up with a gps speedo. Probably a better option anyway because the original clocks are impossible to see with a smaller steering wheel.