The ability of the Jones counter to run backwards is often given as an important advantage in correction for overshoot of a desired mark by backing up the bike. This is only practical for just a few revolutions, and for longer corrections the bike must be turned around and ridden back. Calculations and readings have therefore to be made in the latter case.

Some of the commercial counters are bi-directional and I have just obtained superior results with one of them (Veeder-Root, 799988-412, $23). Like the Jones a correction can be made by activating a switch for count-down mode and simply backing up the bike to the desired reading.

However, unlike the Jones, the bike can be ridden back with the meter in count-down mode. The bike is first moved to the desired rim reading, but no heed is taken of the meter reading. The bike is then turned around and ridden back until the desired readings on shown on the rim and the meter. Alternatively, any rim reading is selected and the bike is then ridden back to any spot with that rim reading.

This message has been edited. Last edited by: Neville,