Does anyone know if a normal clubman speedo will fit a 3 cluster unit?
My needle varies from 80 to 120 k.m. I fillet a new cable.
Any clues?

There are several different Clubman Speedos. The one used in the 2 cluster is interchangable with the 3 cluster. They all look similar and fit-wise are inter-changable, however they are calibrated different for the different diff ratios that were fitted.

There's also clip-on speedo cables in the latter cars, from about 77 on.

<EDIT> if the speedo cable has any tight bends in it it can cause the speedo to flick around like yours, however as you have replaced it, I'd say the speedo head is just knackered out. They have in built damping to stop them wavering about, which I think on these is done with a special lubricant. You may be able to get it serviced, but might not be worth it.

I thought the speedos were all the same and the drive ratio was changes by the little gears in the box?

Actually all the Oz minis and mokes were fitted with the same drive in the gearbox (6:17) and the speedo heads were different. Yes, what you say makes sense and that is how the rest of the motor world does it but......


<EDIT> some of the latter UK models had different speedo drive ratios.