a Mississippi steamboat. It was a modification

that Guinness were perfectly happy with, but

we would still have to run some tests to see

whether the sand tyre would produce more

thrust than a more conventional off-road knobbly.

On a concrete slipway on the banks of the River

Tamar, Graham and Charlie set up a rig to test

the thrust we could expect from the Suzuki’s

rear wheel. We took off the front wheel and

attached the bike’s front forks to the rear of

the test rig, which was set up on a boat trailer.

Then we rolled the whole lot down to the

water’s edge so that the Suzuki’s rear wheel

was in the river. When I gunned the engine, the

wheel would spin in the water and the thrust it

produced would push the bike forwards against

the test rig where a sophisticated electronic

strain gauge would register how many

kilograms of forward thrust we were getting.

Obviously, we had set it up so that the front

suspension wasn’t cushioning the thrust from

the wheel. What could possibly go wrong?

Actually, the fancy strain gauge could. And

when a replacement was tried, that wouldn’t

work either. Then some bright spark said,

‘Hang on. If we’re measuring the thrust in

kilograms, why not just use an ordinary set of

bathroom scales?’

Below: The scooped ridges on the sand tyre were

what made it such a good paddle wheel.

156  hydroplaning motorbike