The materials used in their construction are the same as those used in aeroplanes and even fighter jets.

The 1990s have probably seen more innovation in bicycle technology than any other time.

The intense interest in mountain-biking has pushed backed the boundaries of light-weight and high-strength machines.

BBC News Online spoke to Doug Dailey, logistics manager of the British Cycling Federation and a former double winner of the British Road Race Championship, to find out more about the riders' steeds.

How do the bikes used by the riders vary from the ones you can buy in high street bike shops or places like Halfords?

Essentially although they are lighter, stronger and quicker, the biggest difference is that they are custom made to the rider's needs.

They will be custom sized like a tailor made suit.

How much do they cost, and how much do they weigh?

Britain's Chris Boardman has helped pioneer aerodynamic bicycles

Costs vary hugely, but the standard Concorde road bike our top GB riders use, which would equate to the road stage bikes used in the Tour, comes in at about £2,000, depending on the components specified by the rider.

Some of the specials used in the Tour de France, for the mountain stages where weight is kept to a minimum, and for the time trial stages where aerodynamics come in to play, can cost thousands.

We don't know exactly what they cost but some will be in excess of £10,000. Weight for the standard road bike will be comfortably less than 20 pounds.

What sort of materials are used in their construction?

Although steel still has its advocates, more exotic materials are now commonplace with aluminium, titanium and carbon all popular in the peloton. The GB team bikes have an aluminium frame and a carbon fork.

Is there a massive industry behind bicycle design and construction?

Yes and no! - some of the biggest manufacturers like Giant and Trek - ridden by the ONCE and US Postal teams respectively - are involved.

But there are also many smaller manufacturers supplying the top teams and driving innovation.

The Italians are famous for their beautifully made machines, but British frame builders lose little by comparison.

Last year's winner Marco Pantani rides a modern time trial bike

Will the riders use different bikes for different stages such as time trials or the mountains?

The majority of riders will not change bikes for the mountains, but those in contention for the overall victory and the specialist climbers may well have specially prepared ultra-light machines.

Research indicates that a saving of a couple of pounds in weight can equate to several minutes time saved in the whole race - enough to be the difference perhaps between first and fifth!

Many of the riders will use special time trial machines, our own Chris Boardman among them.

These machines have a very aerodynamic riding position with the aim of getting the rider's back almost parallel to the ground and hands and arms stretched out in front.

The rider assumes a position not dissimilar to a downhill skier's "tuck". The machine may have oval section frame tubes, disk wheels, anything indeed which might help to reduce wind resistance. M

any teams test time trial riding positions and bikes in wind tunnels!

Is there anything special about their gears, pedals or wheels?

Gears may be electronically activated, or traditional cable operated from the handlebars.

Up to 18 gears are available to the riders and ratios are altered according to the profile of the day's racing.

Pedals employ a strapless system - similar to ski bindings - which clips into cleats on the bottom of the rider's shoes.

Wheels vary hugely, from conventional spoked rims to disks for time trials.

We use the popular Rolf wheels which combine a deep tapering rim section and just 16 bladed spokes - both cut wind resistance - normal bike wheels use 32 spokes.

Again, spokes can be a significant cause of wind resistance, so the fewer and the flatter/sharper the profile the better.

What about their clothing?

Bicycle design has come a long way.....

Standard issue is bib shorts, vest and jersey. All are made from breathable fabrics to avoid sweat build up and chilling.

Team cars carry arm and leg warmers and rain jackets for bad weather. These are see-through so that the sponsors name and race numbers are still visible.

Time trials see skinsuits - smooth one-piece suits to cut wind resistance - which may be all-over, or arm-less and leg-less in hotter conditions.

It looks like many of the riders are using mobile phones in the race, is that the case?

Some carry mini-radios with hands-free headsets like those on mobile phones.

But communication within the peloton is pretty sophisticated anyway, via team-mates and managers in their cars, so the extra weight is not welcome.

The best riders tend to hang around at the front of the race anyway and can respond to attacks or tactical situations immediately.

What is the role of the mechanics?

To clean and prepare all the team's bikes for the next stage, fit the correct gear ratios for the terrain. The bikes begin each stage looking like new.

During the stage a mechanic may have to change a wheel if there is a flat tyre - they are just as well-drilled as Formula One mechanics and can change a wheel in seconds.

Neutral service cars also follow the race and carry spare wheels to fit all the bikes in the race - they come into play if a rider's team car is not immediately available.

Cycling's international governing body is going to ban certain bike types - what is going to be outlawed and what does the BCF think of this?

Certain extreme designs are to be outlawed in international competition from next season.

The rule changes are still being thrashed out, but the underlying principle - to make cycling a test of human strength and skill, not technological and financial resources - is a sound one.