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Thread: Speedo recalibration
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Old 04-10-2013
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Quote:
Originally Posted by SeaComms View Post
Picked up the Procal today and went about reprogramming the speedo. It says to measure the tyres to the nearest quarter inch and program that in.

Tyres are Duratracs 285/70 17's. Measure tyre diameter at 33 in exactly and program that in and speedo was reading abot 7k's fast at 80 on the speedo! Dropped it back 1/4 inch at a time and retested and am now back down to 32in and its reading about 2 - 3 km's fast still. Looks like it will need to be about 31.75 in to read accurately.

Is this normal?

Sent from my GT-I9300T using Tapatalk 4
Did you measure and take the average height of the front tyres or measure the spare?
I believe measurements need to be done with weight on the tyres and inflated to around 35psi.