Quicky Q; Correct speedo mech. is 1306; 1536; 1376 or 1408?

[NoBeardNoTopKnot]

A keyboard and a search engine usually reveals all you'd need to know on questions asked a numerous times - only here, that's the problem. Across several forums, this question has been asked too many times and now there's several answers.

I suspect I have the wrong speedo. What is the correct speedo for 7.50 tyres, stock box, stock diff?
Can someone nail this down?

[GHOBHW]

1408 for 7.50 tyres with stock everything

[NoBeardNoTopKnot]

Thanks for that. I think my speedo is S3. The trip makes me say this. With mine being a hot-potch of S2/S3 stock parts, is it possible this changes things? eg; it's a 109 with a Salisbury.

[Alan Drover]

When I bought a new Series 3 speedometer from Blanchard's they supplied a 1376 which apparently supercedes the 1408. The 1376 is for the Stage 1 V8.
I thought my 1408 was causing the speedometer cable breaks but it turned out to be the gearbox drive.
I don't suppose 32 tpm less makes a great deal of difference.

[Wittsend]

The speedo TPI with wheel size is given in our Service Information HERE
Scroll down to the bottom ....

[Birdsnest55]

You can work it out. Try my XL calculator.

Paul

[VOD80]

You can work it out. Try my XL calculator.

Paul

Nice little spreadsheet - thanks! 

Cheers, Tony

[NoBeardNoTopKnot]

When I bought a new Series 3 speedometer from Blanchard's they supplied a 1376 which apparently supercedes the 1408. The 1376 is for the Stage 1 V8.
I thought my 1408 was causing the speedometer cable breaks but it turned out to be the gearbox drive.
I don't suppose 32 tpm less makes a great deal of difference.

And mine a 57 varieties mongrel, later numbers is where the confusion across the forums would come from. To confirm you're running 7.50s?

I'll play with that XLS file. Thank you.

[NoBeardNoTopKnot]

With info from you all I've been able to do some digging. Seems 1376 is the S3 number, and it's common across Minis/ Spridgets / Morry Minors / MGBs and more.

[Alan Drover]

7.50's it is.

[NoBeardNoTopKnot]

Thank you AD. As my witterings in other threads, I've a mod in mind. It's simpler than I thought.