BMW R 100GS Bumble Bee

The R100GS is one of the world's biggest and fastest off-road bikes. It is very good on the road but not so good on the dirt. The GS stands for Gelandestrasse or street scrambler. BMW call it 'a hobby bike, a two-wheeled Range Rover' and the comparison is appropriate. It is not a serious dirt bike but it is one of the best all-purpose bikes ever built. Suitably beefed-up factory versions have won the gruelling Paris to Dakar rally on three occasions. In stock production form, the 100GS has proved a popular choice for riders exploring the world on long distance trips across continents with all types of terrain. It is a 115mph road bike that can cope with the rough stuff. The machine is an imaginative mix of parts that were already available on other BMW bikes, spiced with some adventurous engineering. An example is BMW's patented Paralever rear suspension, a one sided swing-arm with a single gas shock unit. In effect, it is half a swing-arm, but BMW's engineers made it both lighter and 50 per cent stronger than a conventional assembly. The rear wheel is held on by three bolts, there is nothing you could call an axle. The wheel bearing is big, the crown wheel housing is internally stressed since it has to carry the full loads of the back wheel with 7in of travel available. The Paralever rear suspension works admirably, eliminating driveshaft torque reaction. Quick wheel changing is obviously a bonus.

The front suspension consists of leading axle forks offering a luxurious 8.8in of travel. The bike is tall and needs to be for reasonable ground clearance (8.58in). The steering is quick and the throttle response lively. The whole machine is light and nimble with plenty of power and very good brakes. Like all flat twin BMWs, it has a low centre of gravity, so the bike can be chucked around with abandon. The dual-purpose, knobbly tyres are high-speed rated and tubeless thanks to an innovative cross-spoke wire wheel and isolated rim design. The engine is an updated variant of the R80 road bike endowed with typical BMW performance - bags of torque and a wide spread of power — plus some dual-purpose innovations. The bike has a lightweight clutch and flywheel for quicker throttle response, and low gearing; necessary for a dirt bike but lots of fun anywhere since it helps the GS to wheelie easily. On the open road it will hold 1 lOmph for as long as the rider can face sitting up so high and exposed against the wind. Unfortunately what makes it good on the tarmac tells against it on the dirt. The bike is just too big and too powerful. Fully gassed (5.7gal) it weighs 4541b, fine for a road bike but a little heavy for serious off-road use. In addition there is the long wheelbase, the unsprung weight of the driveshaft and two horizontal cylinders that stick out a long way, all factors that conspire against its dirt ability. These are not problems when traction is positive on firm ground but in mud and real rough stuff, the bike bogs down far too easily.

The R100GS is best used as a cross-country bike, sticking mainly to proper roads but taking the odd short cut and back road where necessary. Above all else, the bike is a lot of fun to ride; it is a functional, practical, rugged and reliable all-rounder. Recently, various BMW importers have released Paris-Dakar replica versions of the bike as a tribute to one of the world's most successful desert racers.