Derny (also spelled derney) – “a motorized bicycle for motor-paced track cycling events such as during six-day and Keirin racing) or motor-paced road races. It is driven by a 98cc Zurcher two-stroke engine and by being pedalled through a fixed gear, typically of 70 teeth on the front chainring and 11 on the sprocket on the back wheel [!!]. The combination allows for smooth acceleration and slowing, important when the rider taking pace is centimetres from the pacer’s shielded back wheel. A coupling between the motor and the back wheel ensures the machine will not stop dead if the motor seizes.[…]

The name derny is now applied to all such vehicles, regardless of manufacturer. It is used by the Larousse dictionary as a generic term for a small pacing motorcycle used in cycle races.” *

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Via Ride the Machine.

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Check out the front wheels/forks! The pizza plate chainwheel! Side note – at some point, it becomes easier to go to 2-stage gearing as seen on John Howard’s 152.2 mph bike.

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Via Ride the Machine/Andrew Ritchie.

To those of you who may, justifiably, wonder how this squares with my eschew the hydrocarbons/bike evangelism – I’ll quote Wally Whitman: “Do I contradict myself? Very well then, I contradict myself, I am large, I contain multitudes.” Seriously – though I love bicycles and am going to try to reduce my fossil fuel consumption, I do not intend to be a scold or to turn my back on gearheadish gnarlyness.