A Brough Superior Alpine Grand Sports looks set to become one of the most valuable in the world, as it crosses the block at Bonhams on November 30.

The Alpine Grand Sports is a touring version of the SS100, named after the Austrian Alpine Trial in which George Brough raced

The 1929 bike is an outstanding example from Brough Superior, whose machines are known as the "Rolls-Royce of Motorcycles". It will sell with a £270,000-320,000 ($432,918-513,088) at the Bond Street Sale in London.

A Brough Superior Alpine Grand Sports that was sold by RM Auctions for $465,350 in 2012 is currently in the top 10 most valuable motorcycles ever sold at auction, and this example looks to outsell that version.

Highly regarded by collectors, there are four Brough Superiors in the list so far.

The Alpine Grand Sports is a variation of Brough's legendary SS100, taking its name from the Austrian Alpine Trial. It is designed for touring, with a lower compression ratio, a small fly-screen and a pair of mounted toolboxes.

The SS100 is famed for being sold with a guarantee from owner George Brough that it had been tested at over 100mph, making it the fastest road-going machine in the world at the time. Notable owners include Lawrence of Arabia, who was killed while riding one.

News of the sale comes following the sale of Peter Fonda's Easy Rider chopper, known as Captain America, which sold for a record $1.3m at Profiles in History.

Bonhams has also announced early highlights of its Las Vegas Motorcycle Auction, which will feature a selection of bikes from the collection of Easy Rider co-stars Peter Fonda and Dennis Hopper, as well as the legendary British bike collection of renowned restorer Herb Harris.

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