Ride on air Pedal the foot-pump and off we go. Eric Kendall takes a spin on traditional tobogganing and flies by the seat of his pants.

It's all in the bounce. While sledging is about sliding downhill, snow-tubing has several more dimensions: more ups, more side-to-side, more fun. Just climb aboard a large inner tube and slide down a slope, without the precision of metal runners or worrying about how to steer with your toes.

Compared to the standard craft used for descending snowy slopes - wooden sleds, plastic trays and bin liners - inner tubes are uniquely comfortable and utterly uncontrollable. They also slide on any kind of frozen surface, from ice to the kind of loose snow which bogs down an ordinary sled, leaving snow-tubers in operation on otherwise unsledgeable runs.

This makes tubes perfect for the multitude of UK snow conditions that are normally compressed into the space of 48 hours, mimicking the range of an Alpine season from winter powder to spring slush. And though this kind of versatility is generally found at the expense of performance, it's not the case with tubes: they are fast.

Don't, whatever you do, look for a big hill or a steep one. Tubes are slidier than banana skins marinated in axle grease, and go like the clappers on a moderate incline. There's a smoothness to their acceleration, the feel of a low-speed car-skid on ice where the lamppost across the street looms slowly, inevitably, hopelessly larger. With the slightest push- off you're away, the ride as perfect as mag-lev without the magnets - or the levitation - until you get sent skywards by a bump. It's a magic carpet, with only the stalk of the tube's valve to prod you back to reality.

The total lack of control and omni-directional aspect of a tube means the right type of slope is fundamental to your survival - a gentle U-shape is ideal. Barring catastrophic mismanagement of the launch, the high sides of an appropriate slope keep you safe within the confines of the run, veering scarily from one edge to the other but always coming back to the centre for a tree-free run-out.

Riding technique is dependent on your mood, though lying back and thinking of whatever comes to mind is the norm: climb or jump aboard, legs and arms spread like a starfish over the tube, with your bottom sticking into the centre of the hole. Aim with your feet pointing downhill to start with. This affords terrifying glimpses of upcoming obstacles beyond your boots, but by the time you reach cruising speed and hit a truly inspiring section of terrain, you'll have spun round to see just swirling sky, maybe the top of the slope, and your life flashing in front of you.

Staying on board through bumpy technical sections is largely determined by the length of your limbs. With long arms you can hang on tight; otherwise, a reasonable-sized hillock will fire you upwards out of the tube. If you and the tube carry on in roughly the same direction, you'll land on it again, with another bounce. If not, it's the end of the comfy bit of the ride.

If you manage to stay connected throughout, undulations first cause shock ripples, then waves when you hit the big one - a pneumatic effect that could hardly be called suspension, as it amplifies rather than absorbs the shocks, taking the rough edges off, but giving the ride of your life.

Though unplanned ejections are all too easy, bailing out is virtually impossible thanks to the enveloping hold of the tube around you - it's like trying to sit up on a half-submerged Li-Lo. And that's the essence of tubing. Light the blue touchpaper and recline - just make sure you're pointing in a safe direction to start with.

Tubing basics

Truck inner tubes are available from commercial vehicle tyre dealers - car tyre companies don't normally stock truck sizes but they'll probably know a man who does. At around pounds 25 each, tubes represent stunning value, considering their nautical potential during the summer months.

Tubes can be inflated at a filling station or with a foot-pump on site. An electric pump (run off a car's cigarette lighter) is ideal, and can be found in quality camping and outdoor leisure shops.

Experiment with pressures according to snow conditions. The science of tubing is in its infancy, but generally, harder equals faster; you'll know you've overdone it when you hear a very loud bang. The apparently logical solution to prevent small people from falling off - a smaller tube - isn't practical due to reduced bum clearance. Stacking two small tubes may be a possibility if you can work out how to stick them together.

Tubing dangers are minimal on the right terrain, though involuntary looping- the-loop off larger jumps usually results in head-first landings.

Clothing is as for sledging - it gets hot going back uphill. The traditional tobogganing trick of plastic bags secured over woolly mitts with elastic bands is optional.

Where to tube

Much of the UK's typical tobogganing terrain is ideal. Look for gentle slopes without major obstacles and no sharp rocks - a blowout at speed could be catastrophic.

For more organised tubing try Seefeld in Austria (local tourist office fax: 0043 5212 3355). The resort features a purpose-built run served by a lift. The bobsleigh-style track eliminates the chance of going off course or of encountering skiers, other than James Bond stunt doubles.

Blue Water Acres (fax: 001 705 635 1483) in Ontario, Canada, has a perfectly shaped natural run complete with jumps and skidoo lift service.