There probably wouldn't be too many Australian owners of Samoyeds and other Northern breeds who, at some time, would not have wondered what it would be like to hitch up the team and head off for a sled ride in the snow. The excited yapping of the dogs, the chill wind blowing through your hair, the almost eerie silence as the dogs settle down, broken only by the rush of sled runners on snow, the sheer joy on the dogs' faces - well, what you see is not actually their faces, but you know they're happy anyway. Then you wake up and realise that there aren't too many opportunities to fulfil your fantasy. The typical Aussie sled dog rarely sees snow - in most places where snow is accessible, dogs are banned, and in any case, it's a day or two's travel for most of us. On top of that, not many of us could even hope to put together a team of a dozen dogs - not even half a dozen - most people's realistic limit in Australia is one or two! So when the sport of mushing got off the ground in Oz, it happened in a typically unique and resourceful manner - one and two dog races using lightweight wheeled "sleds" - scooters and converted bikes! Even now, several years down the track, one and two dog classes are still far and away the most popular, and the Aussie scooter is the most popular racing machine. While it's possible to buy scooters from your local bike shop or department store, the cheaper ones have fairly small wheels and a good one will cost you a packet!

Construction of the basic scooter

There are many variations to the racing scooter, depending on the raw materials available and the preferences and skills of the builder. These instructions cover the basic design using a fairly standard BMX bike fitted with calliper (sidepull) brakes. However, I recommend that you consider the advantages of using mountain bike components - see later.

The Seat: Heroes can cut the seat tube just above the upper stays and cap the tube with a 38 mm diameter steel disc welded into place. Mere mortals will appreciate the luxury of a seat. Work out a suitable seat height. Set the seat post at about half maximum extension in the BMX seat tube, and cut the seat tube on the scooter frame so that when the BMX seat tube is inserted, the seat is at the desired height. The top edges of the crossbar and seat stay stumps should be level with the top of the scooter frame seat tube. Remove the seat post and weld the tube into place on these three edges only. Unless you are an expert welder, any attempt to weld directly to the BMX seat tube will almost certainly cause distortion which will prevent the seat post from being inserted into the tube. Fill the gaps with body filler.

So you used a girl's BMX bike, or for some other reason, the crossbar and the seat stays don't line up! In this case, improvise (or learn to braze) - perhaps leave the seat stay stumps long enough so that the front of the seat tube is jammed tightly against the frame's seat tube. Weld to the stumps only and fill the gaps. Alternatively, use a longer section of the BMX bike's seat tube and cut the seat tube on the frame correspondingly shorter so that the weld does not interfere with the seat post when fully inserted.

Finishing: Grind down excessive weld material and use a wire brush and/or wheel to remove flux, corrosion, dirt, old paint etc. Make sure all welds are sound - re-weld if necessary. Give the entire frame a coat of rust converter, paying special attention to welds. Follow with a few coats of rust-inhibiting primer and then a few layers of top coat (sanding lightly between coats). Assemble all of the components and go racing.

A Word on Brakes: If you need to remove wheels in order to transport your scooter, think about buying new callipers fitted with quick-release mechanisms. The rear calliper brakes will not be very efficient due to stretching of the inner cable and compression of the sheath over a considerable cable length. With some additional welding of fittings and brackets, it should be possible to arrange for part of the cable run to be unsheathed, thus minimising one of the causes of the inefficiency. The penalty is that penetration of water and dirt will now be more likely - can't win 'em all!

Mountain Bike Components: The use of mountain bike components is becoming more popular. Advantages include:

• bigger wheels - better on rough tracks,
• often fitted with better brakes,
• sometimes fitted with alloy wheels with quick release axles.

but they're bigger and the scooter will therefore be harder to transport.

If you plan to use a mountain bike, the following points should be noted:

• I would not normally recommend that you invert the rear triangle  - this would result in the dropouts pointing upwards and therefore, a higher risk of a wheel falling off. However, many people have done just this with no problems, and it certainly makes it easier to mount the brakes. Just be sure the axle nuts are tight.
• If possible, use a frame fitted with either cantilever brakes (more efficient than callipers) or V-brakes (better still). If using cantilevers on the front, a bracket will need to be welded to the top of the forks to extend the hitch point in front of the brake cable. Cable routing on the rear will be a bit of a challenge. V-brakes are less hassle and work better. Cantilevers are easily upgraded to V-brakes (at a price). However, beware! ...... front V-brakes give you a lot of stopping power - you wouldn't be the first to sail over the handlebars after "grabbing a handful".