I was cruising on the motorway today, at an indicated 70 mph, sat nav was reading about 65mph.

The car has only done 50k, so I doubt it's similar to my seat, which had done 100k and was over reading by 10%, where I suspected the spinny things that make the needle move had worn a bit and spinny-ed faster than they should.

Are these cars designed to over read? Some safety feature maybe?

Or do I need to consider checking the speed sensor setup?

My Fabs speedo always over reads from new by 10% at low speed if comparison with various roadside radar speed displays are anything to go by.

Nick.

Edited 14 January, 201115 yr by Clunkclick

Most car speedo's over read by about 10%

Edited 14 January, 201115 yr by chrisw880

That's reassuring, certainly helpful for the average speed checks that seem to be spring up everywhere...

Mine was 10% out compared to the satnav and the average speed on the dash (reset and make sure the satnav stays on the same value).

By constrast, the Polo is about 10% out with the satnav, and the climate control unit is about 4mph below the dash. :S

Mine is out, once it said I was off the clock and that reads at 160mph :(

My Fabs speedo always over reads from new by 10% at low speed if comparison with various roadside radar speed displays are anything to go by.

Nick.

Me too.