Either of the speedos for the four speed box will work, but they are smaller diameter (about 3"). There are small differences in the gearing to suit wheel/tyre size and back axle ratio. I use a MkII Ruby type (needle indicator) in my Ulsteroid, with a 5.25 back axle and 15" wheels with fat tyres. It's not too far out in relation to satnav. The earlier speedo has a moving disc showing through a window in the dial, and was fitted from late RN types to the end of the MkI Ruby.

Robert

Location: just north of Cambridge

But they won't look anything like as nice on the dash of the Ulsteroid. The little reversing gearbox previously described looks like a good idea. It's a shame no one has started to make and market them. I'm guessing this has been a problem for a good number of years. Anyone know where to get the little gears?

Robbie,Nick,
Google frizinghall meccano. They do gears both brass and nylon by mail order. I made gearboxes for my pretend Ulster tacho and speedo using these gears. Been working faultlessly for 23 years. The boxes are simple to make : just aluminium 3mm sheet with pressed in brass bushes and bolted together with spacers and bolts as clock mechanisms. The boxes are screwed to the speedo casings.
Dave.

Location: Sheffield

Hi Dave

Any chance you have any photos of your box?? A picture saves hours of doing it wrong lol

Thanks
R

Location: Horsham

Location: Horsham

Robbie,
the thread is 3/4" x 26t.p.i. brass. You should be able to pick up a die a die at Beaulieu.

Best wishes,
Robert.

Location: Deepest darkest Kent

Robbie,
Top photo is tacho drive,bottom one is speedo drive. Speedo and tacho are Ford 10 circa 1950 or so. A Smiths one like yours could be modified similarly.The Ford ones were very cheap to buy from a scrap yard in 1970.Tacho drive is taken from the underside of the distributor using a Ford 10 speedo cable.
The speedo input gear is mounted on the remains of a 1936 A7 speedo so that an A7 cable end screws directly onto it. The 4 speed box has the housing for the speedo drive rotated so that it comes out a few degrees off vertical.
Dave.

Location: Sheffield