Ever since John Foster Fraser and his buddies Lun and Lowe pedalled round the world in the 1890s, the bicycle has been a popular choice of vehicle for the discerning traveller. The most efficient human-powered land vehicle, it is clean, green and healthy to boot.

The standard bicycle is also inexpensive, simple and reliable. Its basic form is similar the world over, with its fundamental parts available in Douala and downtown Manhattan alike. With the exception of remote settlements accessible only on foot, most of the world's population is acquainted with the bike. It can never be as symbolic of wealth as a motor vehicle, and neither is a bike-rider insulated from his or her surroundings by metal and glass. It's a humble vehicle. It is approachable and it is benign. Birdsong and scents are as much a constant companion as voices and faces.

Cycling is slow enough to keep you in touch with life; fast enough to bring daily changes. A fit rider ought to be able to manage an average of 80 to 100 kilometres a day. Pedalling puts you partway between pedestrians and motor cars: a bike can manage a daily distance four times that of a walker and a third that of a car.

Bikes can be carried in planes, trains, boats and cars, on bus roofs and in taxi boots. They can be parked in hotel bedrooms and left-luggage stores. They can be carried by hand and taken apart.

But isn't cycling hard work? Sometimes, but for every uphill stretch or headwind there's a descent or tailwind that's as fun as flying. What happens when it rains? You get wet or stop in a bar. How many punctures do you get? On my last ride (5,200 kilometres), two. How do you survive with so little luggage? It's leaving behind the clutter of everyday life that makes bike touring so fun.

Where to go

If you are doubtful about your stamina, choose somewhere docile such as East Anglia or northern France for your first trip. Beware of being tricked by the map: it's not always the places with the highest mountains that are the most tiring to ride. Scotland, where the roads often follow valley floors, is a lot easier than Devon, where the roads hurry up and down at ferocious angles. The Fens, Holland and the Ganges Delta may be as flat as pancakes, but it is this very flatness that allows the wind to blow unchecked - exhilarating if it's going your way, but not if it isn't...

You may already have a clear idea of where you would like to ride. Hilliness, prevailing winds, temperature, rainfall, whether the roads are surfaced or dirt: all these factors are worth quantifying before you leave. Then you must fit the route with places of interest and accommodation. There may be duller sections that you would like to skip; if so, you need to find out in advance whether you can have your bike transported on buses or trains.

You do not have to be an athlete to ride a bicycle, or even able to run up three flights of stairs without collapsing. It is a rhythmic, low-stress form of exercise. Riding to work or school, or regularly during evenings and weekends, will build a healthy foundation of fitness. If you have never toured before, try a day's ride from home (40 kilometres maximum), or a weekend ride.

Once you know how far you can comfortably ride in a day, you can plan your tour route. Always allow for a couple of 'easy' days to begin with: set yourself distances which you know you can finish comfortably, and this will allow you to adjust to the climate and the extra exercise. It will also let your bike and luggage 'settle in'.

Main roads are to be avoided. This means investing in some good maps. As a rule, a scale of 1:200,000 will show all minor roads. For safe cycling on rough tracks, you will need maps of 1:50,000 or 1:25,000. Stanfords (12-14 Long Acre, London WC2E 9LP, 020 7836 1321) is the best supplier of cycling-scale maps.

The type of accommodation you decide upon will affect the amount of luggage you carry - and the money you spend. Camping provides the greatest flexibility, but also requires the greatest weight of luggage. With (or without) a tent you can stay in all manner of places. Farmers will often let you use the corner of a field, and in some wilderness areas you can camp where you choose (leave nothing; take nothing). With two of you, you can share the weight of the tent, cooking gear and so on. If you are using youth hostels, bed-and-breakfasts or hotels, you can travel very lightly but your route is fixed by the available accommodation.

The best source of information on the geography of cycle travel is the CTC (Cyclists' Touring Club). To join, contact the CTC at Cotterell House, 69 Meadrow, Godalming, Surrey GU7 3HS, 01483-417217.

The bike and clothing

Unlike a motorised expedition vehicle, a bicycle need cost no more than a good camera or backpack. Neither need it be an exotic mix of the latest aluminium alloys and hi-tech tyres. John Foster Fraser covered 19,237 miles through seventeen countries on a heavy steel roadster fitted with leather bags. And while steel bike frames may be repaired by local blacksmiths if necessary, carbon- fibre, titanium or even aluminium alloys will be beyond their skills. Destinations are reached because of the urge to make the journey, not the colour of the bike frame.

Given a determination to arrive, virtually any type of bicycle will do. The writer Christa Gausden made her first journey - from the Mediterranean to the English Channel - on a single-speed shopping bike. My early tours across Europe were made on the heavy ten-speed I had used for riding to school. Spending time and money on your bike does however increase your comfort and the bike's reliability. So does reading Richard's 21st Century Bicycle Book (Macmillan), the updated classic that provides the answers to almost anything velocipedal.

For road riding the most comfortable machine is a lightweight multi-speed touring bike. Gear ratios in the UK and USA are measured, somewhat quaintly, in inches - the given figure representing the size of wheel that it would have been necessary to fit to a penny farthing to achieve the same effect. Richard's 21st Century Bicycle Book (among others) contains detailed gear ratio tables. For normal touring, the lowest gear should be around 30 to 35 inches; the highest, 80 to 90 inches. With these ratios, a fit rider ought to be able to pedal over the Pyrenees, while the top gear is high enough to make the most of tailwinds.

Good-quality wheels and tyres are important. If you can afford it, have some wheels built by a professional wheel-builder, asking him to use top-quality pre-stretched spokes and the best hubs and rims. For continental touring it is handiest if the rims are of the size to take the metric 700 C-tyres. Some rims will take a variety of tyre widths, allowing your one set of wheels to be shod either with fast, light, road tyres, or with heavier tyres for rough surfaces. Buy the best tyres you can afford. Quality tyres can be expected to run for 8,000 kilometres on a loaded bike ridden over mixed road surfaces.

It is very important that your bike frame is the correct size for you. There are several different methods of computing this, but a rough rule of thumb is to subtract 25 centimetres from your inside leg measurement. You should be able to stand, both feet flat on the ground, with at least three centimetres between the top tube and your crotch. The frame angles should be between 71 and 73 degrees. The strongest and lightest bike frames are commonly made from Reynolds tubing. An option for those with fatter purses is to have a bike frame built to your own specifications and size. Many of the top frame-builders advertise in Cycling Weekly magazine and in Cycle Touring and Campaigning, the magazine of the Cyclists' Touring Club.

Generally speaking, the more you spend on your brakes and pedals, the stronger and smoother they will be. Pedals should be as wide as your feet (note that some Italian models are designed for slim continental feet rather than the flat-footed Britisher). Toe-clips and straps increase pedalling efficiency.

Luggage should be carried in panniers attached to a rigid, triangulated carrier that cannot sway. Normally, rear panniers should be sufficient. If you need more capacity, use a low-riding set of front pannier carriers (such as the Blackburn model) and/or a small handlebar bag. Lightweight items such as sleeping bags can be carried on top of the rear carrier if necessary. The golden rule is to keep weight as low down and as close to the centre of the bike as possible. Never carry anything on your back.

Clothing chosen carefully will keep you warm and dry in temperate climates, cool and comfortable in the heat. Choose items on the 'layer' principle: each piece of clothing should function on its own, or fit when worn with all the others. The top layers should be windproof, and in cold or wet lands, waterproof too. Goretex is ideal. Close-fitting clothes are more comfortable, don't flap as you ride, and can't get caught in the wheels and chainset. In bright conditions a peaked hat or beret makes life more comfortable, and cycling gloves (with padded palms) will cushion your hands from road vibration. Choose shoes with stiff soles (i.e. not tennis shoes or trainers) which will spread the pressure from the pedals and which are good for walking too. Specially designed touring shoes can be bought at the better bike shops.

The Touring Department of the CTC publishes technical information sheets on equipment for bike and rider.

Mountain bikes

If you are planning to venture off the beaten track, on rough roads and tracks, a mountain bike will provide strength and reliability. Mountain bikes evolved in California from hybrid clunkers during the Seventies, first arriving in Britain en masse in 1982. Since then, they have become lighter, swifter and stronger. For tarmac riding, a mountain bike is still heavier, harder work and slower than a lightweight touring bike. The mountain bike's fatter tyres create greater rolling resistance, and the upright riding position offers greater wind resistance. The additional weight also requires more pedalling effort on hills. But on dirt roads and trails mountain bikes are in their element: easy to control, with excellent traction and superb resistance to vibration, knocks and crashes.

Mountain bikes generally come with 18 to 21 gears, with a bottom gear of around 25 inches (though in practice five or so of these gears are always unusable because of the sharp angle the chain is forced to make when it is running on the largest front chainring and smallest rear sprocket - and vice versa). Mountain bike brakes are generally more powerful than those on road bikes, and the heavy-duty ribbed tyres are virtually puncture-proof. Lighter tyres with smoother tread patterns and higher pressures can be fitted for road-riding. For sheer toughness a mountain bike is impossible to beat, but you pay for this toughness by pedalling more weight in a less efficient riding position. 'Hybrid' bikes, which fall somewhere between the pure mountain bike and conventional tourer, are extraordinarily versatile: well balanced and tough on road surfaces, fast and relatively light on roads.

Buying second-hand

Buying second-hand can save a lot of money - if you know what to look for. Touring bikes, 'hybrids' and mountain bikes are advertised regularly in the classified columns of the bi-monthly magazine of the CTC, the monthly cycling magazines, and in Cycling Weekly. Before you buy, check that the frame is straight, first by sight, and then by (carefully) riding no-hands. If the bike seems to veer repeatedly to one side, the frame or forks are bent. Spin the wheels and check they are true. Wobble all the rotating parts; if there is a lot of play the bearings may be worn. Above all, buy only from somebody you feel is honest.

On the road

The greatest hazard is other traffic. Always keep to your side of the road, watching and listening for approaching vehicles. In Asia and Africa, buses and trucks travel at breakneck speeds and expect all other vehicles to get out of their way. Look out too for carts and cows, sheep, people, pot-holes and ruts - all of which can appear without warning.

Dogs deserve a special mention. Being chased uphill by a mad dog is every cyclist's nightmare. I've always found the safest escape to be speed, and have yet to be bitten. If you are going to ride in countries known to have rabies, consider being vaccinated before departure. It goes without saying that you should check with your GP that you have the full quota of inoculations (including tetanus) suited for your touring area.

Security need not be a problem if you obey certain rules. Unless you are going to live with your bike day and night, you need a strong lock. Always lock your bike to an immovable object, with the lock passing round the frame and rear wheel. For added security, the front wheel can be removed and locked also. Before buying, check that the lock of your choice is big enough for the job. Note that quick-release hubs increase the chance of the wheels being stolen. Always lock your bike in a public place, and if you are in a café or bar keep it in sight. In most Third World countries it is quite acceptable to take bicycles into hotel bedrooms; elsewhere, the management can usually be persuaded to provide a safe lock-up. The CTC sells travel insurance and bicycle insurance policies.

Expedition cycling

Bikes have been ridden, carried and dragged in some ridiculous places: across the Darien Gap, through the Sahara and up Kilimanjaro. They have been pedalled round the world, many times. And they have been used as a sympathetic means of transport into remote, little-visited corners of the globe. The step up from holiday touring in Europe to prolonged rides to the back-of-beyond requires sensible planning. The choice of bicycle and equipment will have a considerable bearing on the style of the ride. If you want to be as inconspicuous as possible, the best machine will be a local black roadster. Such a bike will probably need constant attention, but pays off handsomely in its lack of Western pretension. I once pedalled across the African Rift Valley on a bike hired from a street market in Nairobi; the bike fell apart and had to be welded and then rebuilt, but the ride was one of the most enjoyable I've ever had.

For serious journeys defined by a set goal and a time limit, you need a well-prepared, mechanically perfect machine. If much of the riding is on dirt roads, a mountain bike may well be the best bet. If you can keep your weight down, a lightweight road-bike will handle any road surface too. On the Journey to the Centre of the Earth bike ride across Asia with my cousin Richard, our road bikes weighed ten kg each, and our total luggage came to eight kg each. We carried one set of clothes, waterproofs and a sleeping bag each, picking up food and water along the way. Our route included a crossing of the Himalayas, followed by a south-to-north traverse of the Tibetan Plateau and Gobi Desert. Objectivity obliges me to note that I've seldom come across other cyclists travelling this light, most voicing the opinion that they would rather carry their cooking stove, pans, food, tent and extra clothes.

Spares

Lightness gives you speed. One spare tyre, one spare inner tube and a few spokes are the basic spares. Rear tyres wear faster than front ones, so switch them round when they become partly worn. For rides of over 5,000 kilometres, in dry or gritty

conditions, a replacement chain will be necessary too. In 'clean' conditions a good-quality, regularly lubricated chain will last twice that distance. The tool kit should include a puncture repair kit, appropriate Allen keys, chain-link remover, free-wheel block remover, small adjustable wrench and cone-spanners for the wheel-hubs. Oil, grease and heavy tools can be obtained from garages and truck drivers along the route.

Saving weight saves energy. Look critically at your equipment, and have some fun cutting off all unnecessary zips, buckles, straps and labels. Discard superfluous clothing and knick-knacks. Make sure there are no unnecessary pieces of metal on the bike (such as wheel guides on the brakes).

It is useful to know the absolute maximum distance you can ride in one day, should an emergency arise. For a fully fit person riding a loaded bike on tarmac, this could be as much as 2-300 kilometres, but it will vary from person to person. With a constant air-flow over the body and steady exertion, a cyclist loses body moisture rapidly, and in hot climates it is possible to become seriously dehydrated unless you drink sufficient liquid. You need a minimum of one litre carrying capacity on the bike; whether you double or treble this figure depends on how far from habitation you are straying. In monsoon Asia I've drunk up to thirteen litres a day.

You may have surmised (correctly) from all this that there are as many different ways of making an enjoyable bicycle journey as there are stars in the sky. I've yet to meet two cyclists who could agree on what equipment to carry.