The bicycle extending sub-frame is produced using standard 22mm steel tube. An adjustable ‘v’ frame is bolted to the front top bar.

The box can be made from a number of possible materials. This example is made of polyethylene and has a capacity of 120 litres

Or it could be made of canvas, wickerwork, aluminium or plastic etc.

First: Take off the back wheel, chain and rear brake. These will be used again.

Second: The sub-frame is bolted onto the rear wheel dropouts without having to cut or weld the cycle frame. This extends the bike to keep the weight between the wheels. Longer chain and cables are standard equipment for a tandem.

The bike now looks like this…

When the Bicycle and sub frame have been bolted together, the rear brake, extended cables and chains can be fitted. The Cargocycle is complete in ‘rolling chassis’ form and able to be ridden immediately.

Third: Putting in the body shell is a simple drop in...

Having built my prototype machine I began to use it as my everyday transport.

My new Cargocycle rode so well, and it was so useful, it made my car redundant. In one step, parking and congestion, petrol prices and road tax, insurance and pollution were just not my problem anymore.

And if that was true for me, it could work for millions of other people as well.

This is a product that could be sold to a world-wide market.

The frame structure, steering and rider position is not altered, so any average cyclist can ride it without any further training. Changes to handling are small and quickly mastered. Gear changing and ratios are unaffected. The cycle has a longer wheelbase which smoothes out the bumps and increases the turning circle. But it is no wider than a standard bike, so it can still use cycle paths and parking spaces.

I developed a light weight version for use by courier companies in London. I used top quality aluminium mountain bikes, attached the sub-frames and fitted an aluminium box…

and they started to sell! (see Development)