Optimistic speedos

[Automental]

No, nothing to do with my trunks but relating to the Chim 400 that I'm picking up tomorrow- v. excited!
I think there was a thread about this recently so apologies.
Was wondering though whether if the speedo is over-reading does that also mean the odometer over-reads, thus prematurely ageing the car?
Anyone know?
Thanks

[occasionaluse]

In my experience the readings are on the high side - and yes this means the mileage reading is higher - in fact mine is 10% higher (measured on long trips i know the distance of).

[Mike Hawthorn]

For what it's worth I check mine against my TOM TOM from time to time and it's bang on! So I can only guess they differ from car to car or the same people who make TOM TOM sat nav also fit speedo's into TVR's ........ Now that's a worring thought!!!!! Good excuss to the girlfriend as to why I take so long on short jouneys though.

[Podie]

My S read over...
The Chim was spot on...
The Griff over reads...

[over_the_hill]

I recently did a rough test on a good stretch of DC. Held car at 50mph on the speedo and timed (stopwatch) how long it took to cover two miles by the odo. Repeated on the way back. Both times within a second or so, gave a value of 7% under !!!
(Did the same in the shopping car and that worked out about right).

However, couple this with the fact that at about 85mph in top gear the rev counter is showing just above 3k so that gives me a theoretical top speed of 170mph.

Clearly something is wrong somewhere.

[Automental]

Yes, I have a feeling the one I'm buying is over-reading at high speeds, probably not much at 50mph.
Either that or it's super-refined and doesn't give a sensation of speed? Not likely!

[Zippee]

My Chim is spot on at 90 (GPS verified by 2 different sat-navs) and only 3mph out at 155 (RAF Marham track day).

My girlfriends MGTF on the other hand is 6mph out at 50, ie/ 50 is only 44 real speed

[mouseymousey]

My Chim is also spot on as verified by GPS. There was a thread a while back about the sense of speed... My car doesn't feel that quick, until you accelerate away from lights and look in your mirror and see how far away everyone else is So it could just feel slower than it actually is.

[WazzaL]

My TomTom indicated I'm going slower than the speedo reads. Speedo 85, TomTom 80.

Not sure at 50. don't spend enough time at that speed to get a fair reading.

[Altrezia]

Mine's 10mph faster accross the whole range!
mad.

[Podie]

Altrezia said:

Mine's 10mph faster accross the whole range!
mad.

If it's consistent, would that suggest that something is calibrated incorrectly..?

Just a TVR quirk really...

[CLN1]

According to the Roadangel my Griff indicates about +5% on average across the range.

Colin.

[nicktowe]

Road Angel shows my G33 to be spot on, but my Audi A6 speedo over reads by 6mph at 85 and by 2 mph at 55.

[buzzsaw]

Spot on at 70 as verified by GPS

[kslett]

Mine is a consistent 10% over according to my tomtom. Although I think my original tyres should have been 205/60s and ever since I've had it they've been 205/55s. 95 Chim.

[That Daddy]

74 Mph is a true 70 Mph according to my sat nav,seems to run out the faster i go