It’s Odometer Day: Here’s five things you never knew about the Odometer

Today is devoted to one of the most beloved parts of your car’s dashboard, the odometer. That’s right, May 12 is Odometer Day!

While the humble odometer records nothing more than the passage of distance, it is incredibly powerful in giving you access to information about your car now and into the future. Log in to your carsales account, check your car into the garage and type in the odo reading, you will be surprised with what you find.

While some may think that there are more worthy car measurement tools to celebrate such as the speedometer and tachometer, over the years the odometer has provoked much bragging and discussion after a few drinks in the pub – from anorak wearers and taxi drivers alike.

Here are five facts that shine a light on the odometer...

New York resident, the late Irvin ('Irv') Gordon holds the record for the highest distance recorded by a passenger car on its odometer. At the time of his death in November of 2018 – possibly due to ennui – Gordon had driven his Volvo P1800 S over 3.2 million miles. He purchased the Volvo new in 1966 when he was 25. The car then cost him US $4150, which was equivalent to a year's wages. Converted to metric, the odometer's final figure is around five million kilometres (5,149,901km).

Utes and farm vehicles do a lot of heavy lifting and plenty of dusty kilometres through Australia's interior to keep this country ticking over. Check out this 1989 Toyota Land Cruiser that has been retired from farm work but still likes to get dressed up and head into town on Saturday nights. It's odometer has been clicking over for more than 650,000 kilometres. On this special day, 'Landy' from Blaxland, we salute you.

Australian Design Rules allow vehicle speedometers a legal margin for error of up to 10 per cent above or below the speed limit. Many car companies, rather than place their customers on the wrong side of the law, opt for conservative speed readings – an indicated reading of 100km/h possibly being as low as 90km/h, in theory. Since the odometer is driven from the same input as the speedometer, it too may be erroneous.

Your car may have covered as little as 90,000km, rather than the 100,000km the odometer has recorded. And that's before taking into account different rolling diameters for non-standard wheels or worn tyres. All of those could have the effect of throwing out the service schedule and may even leave the company open to liability claims after the formal end of the warranty period – if you feel up to practising your bush lawyer art.

In the past, a common means of obtaining the 'input' for speedometer and odometer was a flexible cable that ran from the car's transmission to the back of the instrument panel where it plugged into the speedometer housing. The cable inside the sleeve was driven from the transmission and a magnet mounted on a spring at the speedo end would react to the rotation of the cable moving the speedo needle to a number on the dial approximating the vehicle's speed. Reduction gears driven by the same cable would turn the numbered drums of the odometer.

A setup like this was very easy to corrupt with a 'haircut' – unplugging the speedo/odometer and manually winding the odometer back for a lower mileage to sell the car easier or at a higher price. This illegal practice – not quite as portrayed in the film 'Matilda' – has all but ended over the past couple of decades, following the near-universal adoption of electronic systems that receive signals from the engine management CPU in lieu of the mechanical drive. Moral of the story? Electrons can't be seduced to the dark side...

Mileage – a handy term even in the modern era of metric measurement – only tells the prospective buyer part of the story. In days gone by when 100,000 miles was a long and arduous life for a car, the odometer of many cars only displayed five digits (not including the drum for the decimals). After 99,999 miles (160,932km), the odometer would click over to all zeros. Along with the introduction of metric units of measurement in the 1970s, factors that influenced the move to six digits for the odometer include the much improved reliability of the humble family car, a vastly superior road network and the rising mobility of the average Aussie driver.

These days it's not unprecedented for common family cars to cover distances of 300,00km or more before the vehicle is handed down to a child for his or her first car, or shipped off to the wreckers. Even if the vehicle has been carefully maintained and all those kilometres travelled are on open roads, we as consumers cannot overcome that entrenched worry that a 'high mileage' car is at the end of its life. And that makes vehicle history reports all the more valuable...

But the odometer remains a handy guide to a vehicle's history and its market value, and if you're a carsales member your car's current odometer reading can help you establish what the car is worth if you're in the market to sell.

Happy odometering...

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