MGB Register Forum

On the rear of the Smiths speedo in an MGB is a threaded sleeve that the collar on the outer of the speedo cable screws onto. Can anyone tell
me what the diameter is? Even better if you can identify the thread as well.

Brantz have an adapter which they say is for Smiths and Jaeger with an M12 x 1mm thread. My speedo is in the car at the moment so its not easy to check.

Thanks,
David

Hello David
I doubt it will be a metric thread. I measured a spare speedo cable collar with my vernier caliper. it measured 11.11mm which in old money is o.4375" which is 7/16".
Hope this helps.
Mike