Club G40 Forum

Technical => Engine and Transmission => Topic started by: Jezza-7 on August 13, 2013, 03:02:10 PM

Title: Adjusting speedo
Post by: Jezza-7 on August 13, 2013, 03:02:10 PM
Is it possible to adjust the speedo so its more accurate?

When at santa pod i crossed the line at just over 105mph but on the printout, which im sure is more accurate than my car, said 99mph.

Just something i wondered about and if its possible?
Title: Re: Adjusting speedo
Post by: scotsjohn on August 13, 2013, 04:04:38 PM
Shouldn't think so James, but at least it's erring on the safe side. Adjust your odometer for you though.
Title: Re: Adjusting speedo
Post by: hayesey on August 14, 2013, 09:33:21 AM
that's fairly standard on any car, they always over-read, even brand new ones.  The faster you're going the more obvious it is.  You can tell this by looking at the GPS speed on a sat-nav on the motorway.
Title: Re: Adjusting speedo
Post by: Andy on August 14, 2013, 05:25:59 PM
Current EC regs state no under-reading allowed, but speedos are allowed to over-read by up to 10% + 2.5mph (or something very similar - it's a while since I had to check it!) Ergo many will be designed to over-read by a fair bit to ensure that over the range of component tolerances that you never get one under-reading.
Title: Re: Adjusting speedo
Post by: Jezza-7 on August 14, 2013, 06:05:48 PM
oh right, just something i wondered about.

My audi says 30mph but the satellite says 28mph.

Might look at a small digital speedo that works off satellites. Prob a waste of time though.