Speedo calibration

[Peter Laidler]

Trawled the tech pages and parts lists without success so far. Am calibrating a Mk2 mini speedo, marked:

4421/01-AS. 800 (revs per mile). Marked in Km/h. Cllearly a European instrument but can't find any info re internal gearing. Any of you clever blokes tell me what vehicle this instrument relates to? That way I can do the maths and gearing.

And what about the AS suffix?

Thanks

[Spider]

I haven't looked up the serial number Pete, but our Aussie built Big Wheel Mokes used a 800 TPK (Turns per Km) Metric Smith Speedo, those from 75 on were supplied ex-UK. I'm sure I have the internal gear tooth counts for these, just bare with me, unless someone else can stump up sooner.

<Edit: I've just looked up the S/N and these were also a 4421/11. >

[timmy201]

There’s a calculator here to tell you the most appropriate speedo drive gears

Or if it’s easier 800TPK is the equivalent of 1280TPM

http://www.guess-works.com/Tech/ratioKM.htm

[1071 S]

Just to be pedantic.... You are trying to calibrate the odometer not the speedo??

The odo is gear driven, the speedo is calibrated by changing the distance between the drive and driven plates inside the instrument.

A local shop (since closed) adjusted my speedo after a change from a 3.76 diff to a 3.44 and later to a 3.1. No gear changes involved...

Cheers, Ian

[timmy201]

It makes more sense to me to change the drive gears. Sure you can calibrate the speed independently, but then the odometer won’t read correctly

[1071 S]

Of course it makes sense .... but also costs time and $$$ ...

While an incorrect speedo has the potential to cost a few $$ no one is going to fine you for travelling a few extra KMs.

And the maths aren't difficult

Cheers, Ian

[Peter Laidler]

Thanks for the info chaps and especially Spider Chris.

Tim and Ian, thanks for yours too. I've sent you a pm.