Automotive oddities in the form of Vernier gauges, tyre conicity and magnetic fuel savers require Garageman’s expertise this month
In the interests of protecting him from unwanted fame, stalkers and the paparazzi, CAR cannot reveal the true identity of the resourceful Garageman TYRE DEFECT
In earlier days, many farms were connected by single telephone lines, with the result that anybody could pick up the phone and listen to their neighbour’s conversation. Each farm had a different ring code consisting of a combination of long and short rings so that you knew when to answer. In any community, there were always one or two people who listened in all the time, so that they got to know everybody’s business. We all knew who the culprits were and sometimes used their knowledge to our advantage.
At present, we have an even better system called Facebook. Susan Houghton spends hours on it every day and, since many people add a comment every time a dog barks, she gets to know what’s going on as well as what’s coming off. Consequently if we wanted to hear any local news, we contact who we called “Radio Houghton”.
When Radio Houghton brought her 2014 Ford Fiesta in for a service the other day, she mentioned the steering pulls to one side. Hannes performed the usual service and then took the car for a spin. There was a strong pull to the right so he started to look for likely causes. A difference between front-wheel right- and left-hand tyre pressures is by far the most likely cause but the pressures were normal.
Hannes put the car on a lift and examined the suspension arms for signs of damage. He then checked wheel-bearing play and was on the point of suggesting we send the car to a wheel-alignment specialist when the thought occurred to him that it might be a tyre defect. He inspected the tread on both front tyres but could not see any difference in the pattern. Eventually, he came to me and asked to phone Radio Houghton to check when the pulling first started.
She replied she’d been on a trip and the mileage was right to have the tyre positions rotated so she took it to a tyre shop and they rotated the wheels crosswise front to rear. On the way home, she noticed the pulling but decided to bring the car to us instead of going back. I told her if she mentioned this to us it would have saved some work and time.
Hannes heard this news with joy, swapped the front wheels left to right and went for a drive. The car now pulled to the left, confirming the suspicion that formed in his mind. He examined the left-hand wheel tread carefully using a Vernier gauge and pronounced the tyre was suffering from conicity. This is a manufacturing defect which results in the tread being moulded-in slightly to one side of the tyre, so that it is not symmetrical with respect to the contact patch. This causes a pull if mounted on a front wheel but not if mounted at the rear, which is why the pull started only when the wheels were rotated. Tyre companies will normally replace such rubber and I offered to negotiate with the company concerned.
Do you know most ordinary (non-scientific) pocket calculators sometimes give the wrong answer? This is because they’re not programmed to calculate using the sequence we’re taught at school. It’s called BODMAS and is short for the sequence bracket, of, divide, multiply, add, subtract. If you use any other sequence, the answer may be wrong. The children in our primary school know this very well. One their best-loved teachers has mentioned, preached, declaimed, shouted and whispered “bodmas” so often he’s now known as Mr Bodmas.
Bodmas seemed friendly and intelligent but he suffered from a common mental condition: gullibility. He tended to believe things just because they were written down. Recently, he came across an advert explaining an engine’s combustion can be improved by fitting a powerful magnet around the fuel -line. This would somehow line up the fuel molecules so that they burn faster and hence more efficiently. He bought a magnet and fitted it around the fuel line.
I bumped into him at a party and he soon started to rave about the marvellous magnet baffling engineers. He fitted it a month ago and claimed his fuel consumption has improved by at least 15%. I played along, pretending to be amazed, because I believe the best way to deal with nonsense is to suck all the information out of the talker and then deliver the deathblow at the end.
I asked Bodmas to bring the car to the workshop so that we could take a look at the magnet and measure the fuel consumption scientifically. When the car arrived, we all crowded around it while the bonnet was slowly being opened by the excited teacher. Our curiosity turned to mirth when we realised that the beautiful red circular magnet was mounted around one of the heater hoses!
How come Bodmas measured an improvement in fuel consumption? It’s human nature to drive more sedately, obey all traffic regulations and cruise exactly at 100 or 120 km/h when you’re testing something. You will inevitably get an improvement. A month later, when your old habits return, the consumption reverts to normal.