Is my milage correct?

[Dom]

Hi,
My speedo (not the trunks) is not accurate. it runs about 10mph low at 30-40mph. This doesn't worry me too much, may sort it one day.
But, I was thinking today, if thats showing 30mph when i'm actually doing 40mph, does that mean that the milage on the dial is inaccurate? Have i actually clocked up an extra 10 miles for every hour I have driven at that sort of speed?
Just wondering.
Dom

[Stagdad]

Can you check it against a satnav,when you put in a destination it tells you the mileage to it.
cheers Steve

[jleyton]

I reckon it all depends on where the error lies.

If there's the wrong drive in the gearbox then yes, the speedo and odometer are both reading wrong. But if, for example, the needle is just fitted wrongly then probably not.

Cheers

Julian

[DJT]

Could be the speedometer part has gone 'lazy'. If you haven't got satnav then nip out to the M1 and take note of the distance markers. These are every 100 metres.