This is the bike that Guy Martin rode to a new British absolute speed record of 112mph, drafting a racing truck.
The motorcycle racer and lorry mechanic from Grimsby was filmed by Channel 4 last year, as he attacked the record of 110mph set by Dave Le Grys on the unopened M42 motorway in 1986.
With no unopened motorways available, Martin opted for Pendine Sands in South Wales, a seven-mile stretch of beach with a history of record breaking: it was first used in 1924 by Malcolm Campbell to reach 146mph in his Bluebird. But pedalling a pushbike on sand at over 100mph is hairier than Martin’s cheeks.
For the bike, Martin chose Rourke, a Stoke family business that also has a history of record breaking: Brian Rourke was nine-time BBAR winner Ian Cammish’s frame-builder. His son Jason — with some reservations — made Martin’s frame.
“I didn’t want any part in it, was my initial response,” said Rourke. “We’re busy and I could do without the responsibility of something so dangerous. But then you start thinking, it’s quite interesting…”
The compound gear system, avoiding a single enormous front chainring, was custom-made by another British company, Hope Technology.
Reynolds 853 steel with a housing for a second axle halfway up the seat tube braced to the rear horizontal dropouts with a second set of chainstays. It has a tandem-style eccentric bottom bracket to adjust chain tension to the seat tube-mounted sprocket.
Steel, custom-made by Jason Rourke for a Hope M4 Evo disc brake.
Using a similar compound gear system to Dave Le Grys’s original 1985 bike, built by Cliff Shrubb, Hope supplied custom cranks, bottom brackets and two 60-tooth chainrings. With a 16t sprocket on the seat tube and 15t on the rear wheel, the wheel turned 15 times for every pedal revolution. At 112mph, Martin’s cadence was 97rpm, and the wheel was spinning at 1,460rpm.
Continental Top Contact 50mm. Jason Rourke persuaded Martin to run wider tyres after the first very sketchy run on the beach where he found the bike difficult to control at high speed on sand. And it worked!
Aluminium Easton mtb flat bar with Funn lock-on grips.
Welded to the head tube and containing a mechanism to release the cable to the pacing truck at 50mph via a Shimano Deore brake lever once the massive fixed gear is turning. It also acts as an emergency buffer against a padded bar on the panel mounted to the truck that shielded Martin from the wind.
Hope Tech supplied almost everything apart from the frame, including the stem and seatpost.
Fizik Gobi XM.