speedo accurate

Had these tyres fitted to my patrol The speedo according to the GPS read 100KPH when the actual speed was 98KPH
Ray

I've checked my 3.0 GU against a GPS unit and it showed only 92kmh against the speedo's 100kmh - same tyres with 5000km on them.

I would not rely on the GPS as I have just recieved a speeding ticket. GPS reading 102kph.Speed camera 111kph,so I will using the speedometer in future.

I may be wrong but my experience would suggest that a GPS will only give you an accurate speed reading if it is giving you an accurate altitude reading. In order for it to do this it must be able to see some satelites very near the horizon, driving in you vehicle along most roads (other than deserts or beaches) does not provide this view of the horizon. DAve

Presuming you allow for some wear of the tread. BFG's are a fairly deep tread and blocks and will almost certainly make your wheel taller when new. I changed up to BFG Mud terrain 285/75 16 and then had the speedo re-calibrated. This proved relatively easy and inexpensive because being electronic in the GU and not mechanical they didnt need to use a ratio box. I also got certification. The bonus in running taller tyres for the 3ltr is the revs are 2000 at 100 k/hr and better clearance.