Around about this time last year, we featured an all-wooden bike named SplinterBike that went on to be viewed by over 320,000 visitors to the Power of Making exhibition at the Victoria & Albert Museum in London. A second version was used to set a new speed record for 100 percent wooden bikes in August 2011 and now the creator of both, Michael Thompson, has built a special SplinterBike Quantum (SBQ) edition for the 2012 London Olympics. A few design changes have been made to allow a variety of visitors to the Adain Avion event at the London 2012 Festival to mount up and ride an all-wooden bike for themselves, including adjustable seat height and a different gearing setup.
Launched earlier today, the SBQ is said to have been created in response to the staggering amount of public interest shown in the previous two models, and at the request of Adain Avion London 2012 Cultural Olympiad. This special edition project is being squeezed between SplinterBike model Two and model Three, and will go on display inside the recycled fuselage of a converted DC-9 Airplane as part of the Adain Avion event that kicks off shortly.
Model Three will be revealed later in the year ahead of an attempt to set a new Hour Record for wooden bicycles, where the rider will continuously pedal for 60 minutes without putting his feet down, with the total distance traveled being recorded as a new record.
Thompson says that he's so far spent around 1,600 hours designing, prototyping, building and testing the various versions of SplinterBike, and has put all that experience to good use when creating the Quantum edition. One of the first tasks of the new project was applying the adhesive tires to the wheels, as it's said to take five weeks for the glue to set hard enough to hold its shape while under load. The glue tires now benefit from an improved full radius profile courtesy of a hybrid polymer adhesive supplied by Tremco Illbruck.
The SBQ is made up of 88 individual components which took 40 hours on a CNC machine to produce. Thompson spent another 400 hours sandwiching all the pieces between the new bike's monocoque frame and, despite design decisions aimed at keeping the weight down, the Quantum actually ended up being 6 kg (13.2 pounds) heavier than the original at 39 kg (85.9 pounds). The extra weight is due mainly to substantially larger ply gearing and the reclaimed Ekki (Azobe) bottom bracket (salvaged locally from the River Thurne in Potter Heigham).
The new bike still features the innovative pliCog transmission gearing, but there have been some changes made. The gear ratio has been reduced to 2.5:1 from 4:1 on the earlier bikes, as it was found to be somewhat tough on the plywood gear teeth, hence an increase in tooth size, too.
"In theory, the 224 teeth on the six pliCog gears should propel the bike to a speed of 33.33 km/h (20.7 mph) based on a rider cadence of 100 and 56.66 km/h (35.2 mph) at a sprint cadence of 170," said Thompson.
The handlebars have again been made from old broom handles, but they now feature extended aero-bars to cater for an improved riding position. The height of the handlebars can also be adjusted to accommodate a greater variety of riders, as can the seat height. The self-lubricating Lignum Vitae used for the bushings was fashioned from some redundant wooden bowls donated by the Acle St. Edmunds Bowls Club.