Audi's bike weighs less than an Apple MacBook

German prestige carmaker Audi has applied some of its know-how in lightweight materials and engineering to a vehicle with two wheels instead of four, and pedals instead of a motor.

The result is a bicycle that, stripped to the frame, reportedly weighs less than an Apple Macbook Air at a rather lithe 790 grams; with full componentry in place it tips the scales at a still measly 5.8 kilograms.

With fewer kilograms to crank up those hills, you can enjoy a couple more lattes and perhaps even a vanilla slice when you get to the top.

The Audi Sport racing bike was first shown at the Geneva Motor Show in March, before hitting the showroom floor in Tokyo this week.

The bad news is that you'll never be able to ride it in any UCI-sanctioned races (Le Tour de France, or the Giro d'Italia, for example) unless you stick a kilogram of lead to the seat post to bring it up to the 6.8kg legal minimum. The good news is that your local bike club probably won't notice - unless you start winning some stage races.

With a carbon frame made by Japanese company Toray, the Audi shapes up as one of the lightest bikes available. Much of that has been achieved by the use of the high-end T1000 carbon which is reportedly used in Audi race cars. Other weight-saving elements include the use of Meilenstein carbon-fibre clincher wheels, and a Shimano Dura-Ace Di2 groupset.

Battle of the lightweights

Still, the $24,650 Audi looks positively beefy and somewhat overpriced next to Trek's $15,990 Emonda SLR 10, which weighs in at 4.65kg (the OCLV 700 series carbon frame is just 690 grams), making it the lightest production bike on the planet.

Well, it was until last week, when Merida released its featherweight Scultura 9000 LTD at the Giro. With a frame weighing 680 grams and the complete bike only 4.55kg, you have to wonder how light bicycles can get before strength and manoeuvrability is overly compromised.

Mind you, none of these bikes rates a mention against the positively anorexic machine once owned by cyclist Gunther Mai, and later by a rider from Colorado. The fully custom-made bicycle is hardly there at all, at 2.7kg - less than the weight of the average newborn baby. The frame itself was built by Spin and weighs a silly 642.5 grams. Some of the wheel components utilise carbon fibre from the F1 industry. Estimates put the bike at around $US45,000 ($56,000) but it's difficult to say, as every part has been hand-built.


The car creed

Audi is by no means the first prestige automotive marque to introduce a lightweight pedaller to its range. In 2006 Mercedes Benz came out with a limited edition 8.1kg carbon road bike that sold for around $4000. For its time it was quite a neat piece of kit, and more importantly It had a three-point star on the headtube.

Not to be outdone, in 2012 Aston Martin offered the One-77 Superbike, inspired by the hypercar with the same badge. Made by Factor Bikes in Norwich, England, it set punters back a cool £25,000 ($49,500). The 9.5kg build weight was a tad on the hefty side, even then.

And Lamborghini recently teamed up with Swiss bike company BMC to produce the Impec; a bicycle that was limited to just 50 examples worldwide and appealed to folks who had almost $50,000 to drop on a two-wheeler, albeit one weighing a respectable 6.85kg.

Only 50 of the Audi Sport racing bike will be built.