05-06-13, 06:08 PM
Steve, they don't NORMALLY do you for 71. Nothing to do with inaccuracy, just too much of an argument. As you say, they like a watertight case so tend to go with the 10%+2mph guideline. For most drivers this would mean a speedo reading of well over 80mph before actually getting a tug from the plod.
Most people don't realise that the speedo on a car or bike varies by about 3% over the life of the tyres due to slightly different rolling radius affecting the distance travelled per revolution.
Legally, a speedo can OVEREAD by up to 10% (though I did hear some EU bollox about it being 20% but don't believe it made UK law) but can NEVER under read. In other words, your speedo could read up to 77mph before you exceed 70mph in reality. It will never read less than 70mph when you are actually doing 70mph.
Most people don't realise that the speedo on a car or bike varies by about 3% over the life of the tyres due to slightly different rolling radius affecting the distance travelled per revolution.
Legally, a speedo can OVEREAD by up to 10% (though I did hear some EU bollox about it being 20% but don't believe it made UK law) but can NEVER under read. In other words, your speedo could read up to 77mph before you exceed 70mph in reality. It will never read less than 70mph when you are actually doing 70mph.
Another ex-Fazer rider that is a foccer again