Odometer
The distance counter built into every vehicle and the simplest form of distance recorder. Usually too imprecise for rally navigation – the more accurate tripmeter is used for that.
An odometer is an instrument that measures and displays the distance travelled. A distinction is made between the total odometer, which records a vehicle's overall mileage, and the resettable trip odometer for individual sections. Mechanical odometers count wheel revolutions via a gear train, while modern ones work electronically via sensors.
In regularity rallying the standard odometer gives a rough guide but is usually too imprecise for exact navigation: it often rounds to 100 metres and deviates depending on tyre size, tyre pressure and wear. Teams therefore use a calibrated distance meter – the tripmeter (such as the Halda Tripmaster) – which records distance more finely and reliably. The distances given in the roadbook are checked against this device.
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Related terms
Tripmeter
A precise supplementary instrument for measuring the distance driven – more accurate than the standard odometer. The co-driver's key tool, often called a tripmaster.
Regularity rally
Classic-car motorsport where precision counts, not speed: hold prescribed average speeds and target times as exactly as possible.
Distance recorder
Umbrella term for any in-car device that measures distance – from the series odometer through the more precise tripmeter to digital and GPS-based units. It provides the basis for every distance instruction.