New Ruby owner - an introduction

[David Stepney]

Usually its not the odometer that is inaccurate, provided the speedometer head is the correct one. My own speedometer reads slow and is about 5 mph pessimistic at 30 mph. The odomenter part merely counts revolutions of the speedo cable and is entirely mechanical. The speed indicator part has a rotating magnet inside an aluminium drum to generate eddy currents which tend to drag the needle (or drum itself if of the 'Magmo' variety) around the dial. Over the years, the magnetism fades and I suspect this is the cause of the inaccuracy of speed indication.