Hello everyone
Whilst looking for an appropriate Speedo for my Heerey project (till I get my workshop sorted I can only collect bits!) I found that a Reliant Robin/Rialto 1992 to 1997 has a 100mph 100mm speedo, this is still is a 10" wheel car, they are easy to pick up on Fleabay too!
If you have a 13" wheel car then you can use the later LX cars ('96 on I think) that had 12" wheels, these go up to 140mph! Why on earth you would want to do that in a Robin I have no idea...
Here is one with all its other dials too
http://www.ebay.co.uk/itm/Reliant-robin ... 1555753224?

It's not just the wheel size that determined whether the speedo will be suitable though.

It also depends on speedo drive ratios, final drive ratios, where the speedo drive is taken and a few other factors too.

it's not really that critical though as Speedy Cables can recalibrate most speedos to suit most applications.

All they need to know is

1. How far the car travels with one revolution of a road wheel.

2. How many turns the speedo cable makes during one revolution of the same wheel.

As you say it does depend on many factors, I was more pointing them out a as good and cheap source of a speedo.

hey, did you ever consider an electronic speedo?
I picked up a speedo/gearbox sensor, and with the speedo you'd be able to adjust or calibrate yourself.

That's what I'll do with mine as it's newer, lighter and it doesn't have that clicking sound as the wire revolves inside the cable.
http://www.digital-speedos.co.uk/classi ... -158-p.asp

It's certainly more expensive I think. Compared to a new cable second hand speedo and calibration, but the other advantages are clear.