Calibrating speedo - Do it yourself?

[George Smathers]

I have a NOS stock 1504 speedometer that I need to calibrate for my 3.9 differential. In the States this costs $200. Is there some way I can just change the gear myself? Does anyone in the UK sell the gear? I'm not looking for GPS accuracy, I just want the speedometer to be close.

Thanks,

George

[chesney]

If it's just to be close, place the needle at the speed you want it to be most accurate at - for eg, 50, drive at a known 50mph and plonk the needle on.
Short answer is no, although I've experimented with adding magnets with mixed results.

[George Smathers]

Chesney,

That's an interesting solution. The truth is I only really look at the speedometer when I am in a 30 mph zone so that might work.

George

[daveyl]

It might be worth trying it first, as even NOS speedos can vary in accuracy.

[bmcecosse]

It may not be too far out -although a 1408 would be better. I can tell you that a 1248 is perfect for miles and speed with a 3.7 final drive (and 155 x 80 x 14 tyres). See this advert - and he has a 1248...... http://www.ebay.co.uk/itm/Smiths-Speedo ... 58a62d4553

[Nickol]

After digging through the archives I have come across this thread and as ever Roy, you supply the answer.....

Now, a year and more after the event a question. There are some second hand speedos available , (presumably from a Mini) which have the "1248" after the description. (i.e. "Code reads SN 6401/56 A 1248")

would this be suitable for my newly installed diff with 3,7 to 1 ratio on my Morris trav 1048cc?

[bmcecosse]

Well - as I said before - mine is 'perfect' with a 3.7 final drive so it won't be too far away with a 3.9.

[Nickol]

Many thanks...where would we be without you?

[bmcecosse]

happy to help -but there are plenty of others offering help and excellent advice too!