Tuthill Porsche Twin Spare Wheel Bonnet

We’ve been playing with 911s for almost 40 years. Here’s a little bit of our history which recently revisited the workshops at Wardington.

When we first ran in marathon and endurance events, one big challenge was how to carry the regulation two spare wheels. Porsche tried a variety of solutions, including modified fuel tanks that stood the wheels at a more vertical angle, and the famous roof racks, as seen in all those old Safari pictures.

We soon decided that the exterior shape of the 911 was not to be tampered with, as the effects of a loaded roof rack on aerodynamic efficiency, fuel economy and centre of gravity were all undesirable. We began experimenting with different underbonnet layouts, which led to us trying this bonnet design on a number of our early cars.

The elevated ‘smile’ section gives a nice level platform for light pods and allows a pair of spare wheels to sit in the standard location. Preserving much of the lugggage space made this bonnet quite useful for cars running unsupported (with no backup crew), but did mean the fuel capacity was restricted to standard, unless additional tanks were fitted.

Nowadays, we run most events with mechanic support, so we have developed alternative fuel tank arrangements, with a pair of spares in the stock tank location under a standard bonnet, but it’s always interesting to look back at early innovations and consider what use they might be now. Everything comes back into fashion one day.