Kingcyle Computerised Cyclist Turbo Trainer Miscellaneous Notes

MISCELLANEOUS NOTES

The following is a list of answers to random questions asked by users over the years.

The size of the roller is not important to the calibration of the trainer. All the diameter does is tell you how far the rider would have gone in a distance related test and make it harder (smaller) or easier (larger) to accelerate the flywheel in a given time to a given speed, in other words changes the gearing of the bike slightly. The original trainers based on the Amstrad 8256 had 3 different interchangeable sized rollers to try to make the feel of the trainer more closely simulate the feel of the road, with small medium or large riders, which is why the trainer is designed with only one bearing support. It was found in use however that testers did not bother to change the rollers from the largest rider size (smallest roller) so now the trainer software only expects the small roller and no longer has the interchangeable rollers. The thickness of the rubber sprint sleeve can therefore be ignored for all practical purposes.

The sensors are infra red.

The testee should do the calibration as his weight and riding position makes a difference to the calibration. The calibration should be considered part of the warm up.

On original Amstrad trainers the curve was built from various run down tests and stored on disk. When the IBM got faster the curve was analysed with curve fitting software which showed the curve to consist of only a linear (rolling resistance) and cubic (wind resistance) equation. This equation is now used to create the power output you see on screen. The curve fitting software is supplied with new trainers so that is the trainer is taken to higher altitude it can have the curve recalculated. The equation supplied is for normal altitudes found in the UK.

The bottom bracket support raises and lowers the rear wheel on the roller which effects the rolling resistance and hence power consumption of the trainer. The rolling resistance is used to calibrate the trainer for day to day use.

Flywheel manufacturing data:
Diameter 0.1 mm in 190mm .1/190*100 = 0.0526 %
Width .05/18*100 = 0.27%
Weight 3.442/4611*100 = 0.0746%

System Inertia: The inertia of a rotating body is I=mk².
m = mass in kg.
k = radius of gyration

The radius of gyration (k) needs to worked out from tables for each type of body first, by dissecting each body into it's component parts.

Each part also needs to be measured and weighed.