Speedo rebuild suggestions

I am enquiring if anyone has done any rebuilding of Mk IV or V speedos. Specifically what I would like to do is swap the odometer wheels from a V speedo to a IV. I don’t know how the wheels are fitted onto the shaft. The reason I can’t just swap the complete head unit is that the zero setting knobs are at entirely different angles.


Here is what is inside an XK120 speedometer.

I would think all these Smith’s units of that era would be pretty much the same, except they are set up for different axle ratios and tire sizes. I remember swapping the little fiber gears that drive the number wheels because the ones in my 120 were stuck with old hard grease and the teeth were stripped just from turning the cable.

1 Like

The IV is the same configuration as this, ie the reset spindle is vertical/parallel to the dial. The V has the spindle angled back, probably because the facia is angled back a bit.

Dismantling the number wheels from the frame is a mystery for me so far and maybe they are not intended to be separated.

The pointer is only secured to its shaft by the friction of a taper. Be very careful when removing the pointer that you don’t break the shaft. You may find that a very small amount of twisting in addition to levering evenly from both sides will work. It’s very easy to break the shaft.