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Reply to "Electric Bikes for measuring hilly courses with weak legs?"

Ron,

The Kalkhoff Agattu is a nice bike for an elderly or feeble measurer looking to extend his measuring life.

On Tuesday I measured a trail race. I dont normally bother with trail races since they are not certifiable, but it was good to try it out on hard somewhat rough cycle trails in the ancient Forest of Dean. Some modest hills, I was in minimum power assist mode, i.e. equivalent to an electric rider of zero weight adding with 50% of my power output. Well perhaps not quite zero weight: the battery weighs 3.1kg and then there is the motor. The whole bike plus battery is 23 kg. Anyway I left the race director walking on the steeper uphill sections while I pedalled steadily up in 1st gear. The race director is a former 2hr 13 min marathon runner - not at all fit now. So that is no big deal. I am due to ride the London marathon course with Dave Cundy and Hugh Jones next week: that will be a more serious test of my performance on the electric bike.

Meanwhile I have been checking the temperature coefficient of the calibration constant. The bike has come with fairly fat 35 mm cross-section diameter tyres, Continental Townride - puncture protection. The tyre expands by 180 parts per million per degree C. A change of 5.5 C will take one through the whole SCPF. So it is worse than my old Michelin World Tour (116 ppm/C) - but that tyre is narrower 32mm vs 35 mm.



I have not pumped the tyre up at all since receiving the bike and I am tracking the deflation, by using the equation of the straight line fitted to the data to calculate the calibration constant at 10C. This is shown in the second graph. There is no clear trend yet. I probably need to continue for another a week. At any rate I am getting the impression that the inner tube is not leaking air as quickly as I have experienced before.
Last edited by mikesandford
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