Re: Speedo is miles out
Posted: Sun Nov 01, 2015 10:39 pm
Since Jack is comparing two radial tyres - I doubt any of that is significant - neither is a 0.8% difference ! 
The starting point is not a standard Minor size, so the speedo will be a bit out to begin with.
Ultimately the speedos listed from eBay will give you an accuracy that is at least as good as most modern cars have!