Thread: Defer Speedo Too Hi

As said above, all speedos are allowed a margin of error and the manufacturers set them normally about 3-4% higher than road speed.

I could be wrong here, but from memory the current rules are road speed must equal indicated speed minus 3km/hr +/- 5%. It used to be road speed +/- 10% but they reckon speedos are more accurate now.

My Stage 1 read 20% out (said 120km/hr at 100 by the GPS). I swapped the speedo for a NOS one, and it now reads precisely correct. In older ones the magnets wear out and need to be re-magnetised. In electronic ones, there are adjustments (as mentioned) that you can add to correct.

I had an old motorbike that read 10km/hr low at all speeds. I guess it would have met the standards provided I was travelling fast enough

Have this problem with the S1 (Leon) as well. Although it's worse. At indicated 55Mph it is actually doing 70Kph

bloody amazing things the S1...

built purely imperial and they know to belt along in metric!

gotta love em :P

Originally Posted by scrambler

.. It used to be road speed +/- 10% but they reckon speedos are more accurate now.

Another contentious policing issue as far I am concerned, I don't think the ADRs have changed

According to those courtesy speed check signs they put a roadworks mine is travelling 5k's slower than indicated as well. I don't care, looking at traffic I think all cars must be similar because I always seem to keep up when I'm showing 100k's

The speedo in my 1994 Disco indicates 100km/h with an actual of 95km/h with 225/75 16 tyres. With 255/70 16 it read 100km/h at 100km/h.

I had the Jaycar speedo corrector on my last car (Rodeo) and it worked well. I also put a switch in so I could go from my 31in tyres to my 225/75 16 tyres.
I have noticed there is a new version of the kit available. I don't know what they changed.

Originally Posted by Mykeeta

Speedo reads at least five Klms high, according to the GPS. My wife’s Disco does the same but I thought it was the smaller tyres, but no the Defer does the same and it has larger than normal tyres.

The difference in the tyre size between the Disco and Defender won't change anything. The speedos will be calibrated to suit. Assuming you have standard tyre sizes on both.

I can live with my 5-6% speedo error but the odometer error is annoying. Still, it makes me think I get around 10.5 litres to 100km rather than the actual 11 I'm getting.

It has done 9000 less kms than the odometer says but of course try convincing a buyer of that! I guess I'll have to keep it.