E-Bikes: Useful for Training?
29 Dec 2015
For over six months I have been able to use a top-of-the-range E-BIKE to complement my training on the road.
The bike, including the engine and battery, weighs about two kg more than the average road bike: definitely a hindrance on the climbs, but not much of a problem on flat courses.
The engine basically forces a pedal stroke similar to a fixed gear, although the system software allows the choice of the most suitable cadence depending on the intended training.
The engine develops the maximum power at high pedaling cadences: 90-110 RPM.
In order to stop pedaling, the engine needs to be switched off with a wire-less stop button; stop pedaling with the engine still running can damage the gears.
The system has three "power gears", each activated by repeatedly pressing the start button of the engine.
I have thoroughly tested the E-BIKE on a climb of one km at an average gradient of 7%, and compared watts and lactate.
The powermeter was on the hub of the rear wheel (Power-Tap); the lactate was measured with an ARKRAY Lactate Analyzer.
The graph below shows the power measurements and corresponding lactates:
- when the engine is off (black)
- in first gear (green)
- in second gear (red)
- in third gear (blue)
As can be seen, at 4.0 mM/l of lactate the first gear adds about 20w, the second gear adds about 45w, the third about 150w, with regards to the power when the engine is switched off (305w), allowing to develop 325W, 350w and 450w respectively.
The battery life varies according to the use, lasting from about 2 hours in first gear, down to about 30min in third. On the model I have, it is possible to mount two batteries, one internal and one external to the frame (as a "water" bottle), thus doubling the autonomy.
Riding with the assistance of an electic engine allows for higher speeds, simulating the training behind a motorcycle, with the added benefit of fixed gear pedaling useful to improve the pedaling gesture itself.
The use of an E-BIKE during training therefore makes it much easier to organize specific sessions when a motorcycle/vehicle is not directly available for training purposes.