(of the sidecar wheel, towards the motorcycle, measured at the front of the front wheel tyre and the rear of the rear wheel tyre) for a motorcycle on diagonal tyres the formula is:
lead in cm's X 2 = toe in in mm's
For a motorcycle on radial tyres this is:
lead in cm's = toe in in mm's
Here too, a margin ± 10% is acceptable.
Ed Pols developed his own formula for the key measurements of motorcycle-sidecar geometry. Universal rules of thumb that are very handy, especially when mounting the sidecar for the first time. The standard measurements are calculated as follows:
Lead: (centre of sidecarwheel to centre of rear wheel, measured parallel to the longitudinal axis of the motorcycle) dry mass of the motorcycle in kilograms = lead in milimeters (for example: when the dry mass of the bike is 220 kg's, the sidecar wheel lead should be 220 mm's). A 10% margin is acceptable.
|Lean out of motorcycle:
on diagonal tyres 2°-5°
on radial tyres 0°-3°
as narrow as possible
Sidecar position :
horizontal in all directions (measured on an unloaded rig, standing normally on it's wheels).
|The sidecar wheel is not positioned next to, but forward of the rear wheel. The distance between the wheel axles is called "lead".|
|The sidecar wheel does not point straight forward, but slightly towards the front wheel. The difference between the measurements "A" and "B" is called "toe in".|