The trike has one of those bicycle trip computer things, which amongst other things is supposed to tell you how fast you are going.
Only problem is that it was only good at reading zero.
They work on the basis of sticking a magnet to the wheel, and then a sensor monitors when it goes past.
I found a bit of magnet lying around, and then spaced out the sensor so the two parts passed very close.
Spinning the wheel, by hand, has proven that I can average 4 mph.
I did manage to peak at 7 mph, but nearly lost my hand into the monster brake calliper whilst avoiding it getting jammed in the mud guard.
As mentioned in my previous post it was raining, so no test ride.
Though, the plan is to strap the GPS on the trike somewhere so that I can check the accuracy of the permanent one.
The bicycle computer is set for the right wheel size, but tis better to safe than sorry.