Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Re-calibrating Speedo

Found the thread re 4/4 Sport speedo calibration:
http://www.talkmorgan.com/ubbthreads.php..._4_4_#Post98086

"IF" it is a VDO speedo, the instructions are here:
http://www.nsifleet.com/pdf/ProgrammableSpeedometer.pdf

...but it may not be one. Mine (2004 4/4) looks very much like a VDO though I haven't tried checking it (turn on ignition while holding in button) yet. Most modern speedos are electronic and can be programmed, they get their signals from a gearbox sensor and they count pulses per mile.

The "Smiths" brand speedo are built by Caerbont Automotive Instruments. Which is a management buy off from VDO. On their Website CAIGAUGE.COM is also a instruction how to recalibrate the speedometers. My speedometer also showed a few km/h less and I recalibrate it myself. Some GPS receiver say that you drive with 1-2 km/h while standing in front of a traffic light.

Keep mooging,

Christian

One of my old colleagues got stopped by a motor cycle policeman a number of years ago on the A3 up to Petersfield, as he was travelling above the speed limit. It was obvious to the policeman that "Pongo" (ex RAF) was no speedster and it was suspected that the speedo was inaccurate. So with Pongo in the lead they set off and at 30, 40, 50, 60 and 70 MPH, the policeman flashed his lights so that Pongo could mark his speed to indicate those speeds. After
a short friendly exchange to confirm the findings, he was let off on his way with a friendly wave. I like to think that the vast majority of our police service are good folk.

on my 4/4 sport i have used the method above ,and put the correct code
Now the speed indicated is exacly the correct speed

Christian, that is a top link you have posted. This forum needs a sticky list of suppliers and parts sources and this should be on it!

The instructions for the speedos with a front face button are HERE
http://caigauge.com/page28.html

Much the same as for VDO instruments

Nigel

Until we moved to Switzerland a few years ago, I used to time speed events for the RAC MSA and ACU, whilst the GPS is an accurate system, a deviation of 1 or 2 mph against a speedo reading is quite normal, the accuracy of out timing equipment (Tag Heuer) was internationally recognised and calibrated and our measured distances were accurate to 6mm over a mile, an accuracy I don't think can be achieved with a GPS. Also the wear on tyres, even tyre sizes can make a difference to speedo readings, so if you are within a couple of mph I would be happy with that.

Yup,
Provided the speedo does not under-read...
Yes, there is a certain amount of dithering with GPS, accuracy deliberately reduced for non-military apps...

It's the same because CAI was formerly the VDO part which produced Morgan's VDO gauges. They still produce the same stuff but sometimes with other dials, bezels etc. and "Smiths" instead of VDO Branding. BTW according to Wikipedia Smiths was bought by VDO years ago. So the circle is closed now. They have also a repair department called "Speedy Cables". It has its own website.

BR

Christian

I wet out in Aldermog todat, for the first time with a working GPS (TomTom Rider 2). I know the TomTom is spot on at 30mph and was VERY surprised to find the Mog's "Smiths" instrument is exactly corect. It was also correct at 20, 40 and 50, I didn't have an opportunity to check at higher speed.

This is, in my experience, almost unknown. Our 2011 Mercedes reads under by 3mph at 30, the 2013 BMW is 2,mph under and my late Triumph Tiger also under read by 3mph at 30.

So, out in Aldermog I need to take more care.....!