Speedo accuracy

[craig_tvr]

I have a '94 4.0 Chimaera and question the accurancy of the speedo.

Whilst travelling at 70 my GPS shows that i am only doing 63, and to make the GPS read 70 the cars speedo shows almost 80.

Does anyone else suffer from this degree of error?

[ribol]

I did the same test, although my Chim has the later Griff 16" rims front and back with brand new 225/45ZR16 front and 245/45ZR16 rear.

Mine showed the following:

Speedo 60, True 56
Speedo 70, True 63
Speedo 80, True 73

Ivan

[general_lee]

I'm the same - had me girlfriend drive along at 70 in her Renault and I followed behind - the speedo was just short of 80mph. Figure it's about 10% out and I now drive accordingly except through speed cameras when I adhere to my speedo!

[greenv8s]

I have a '94 4.0 Chimaera and question the accurancy of the speedo.

Whilst travelling at 70 my GPS shows that i am only doing 63, and to make the GPS read 70 the cars speedo shows almost 80.

Does anyone else suffer from this degree of error?

My V8S used to read roughly 10% too. Fortunately there's an easy fix - with the diff changed to 10% taller gearing it's now spot on!

Peter Humphries (and a green V8S)

[manek]

About 10-15% over seems to be about standard. It's the same as my (now ex) Chimeara used to show when I checked it against a GPS.

[the dodger]

We've been here a few times before.......
All speedometers may read up to 10% high but must not read low. Tachometers tend to be more accurate so check using 28mph / 1000rpm in 5th (standard set-up).
3000rpm should read between 84-92mph.