Nearly two-thirds of Britain’s motorists use filling station air pumps to inflate their tyres – and they could be putting lives at risk, a Tyre Gauge survey for the IAM Motoring Trust has revealed.
“The danger is that the drive to the filling station increases tyre pressure significantly,” says Tim Shallcross, the IAM Trust’s Head of Technical Policy and Advice. “This means that, although the pressure gauge may be accurate, tyres can be under-inflated by between 12 and 15 per cent. The survey shows that two thirds of motorists inflate their tyres at garages, therefore vehicle and tyre manufacturers should consider changing their recommended settings to ‘warm’ pressure levels.”
The downsides of under-inflated tyres:
- tyres run at a higher temperatures than they are designed for, especially at high speeds; overheating is a common cause of high-speed ‘blow outs’.
- road grip and handling are adversely affected
- fuel consumption increases; remember the link between pounds per square inch (psi) and pounds per mile travelled
“For all these reasons drivers should check the tyre pressure weekly,” says Shallcross. “However, the survey shows that we’re not checking tyres frequently enough, with just 18 per cent of men and 4 per cent of women drivers doing so weekly.”
The era of ‘free air’ at garages appears to be ending. However, charging for air does seem to be improving pressure gauge accuracy. The IAM Trust survey shows more than 80 per cent of air lines to be accurate within 5 per cent or 2psi, a significant improvement on the 2005 check, which found 50 per cent of gauges to be inaccurate. The new survey also shows that 71 per cent of drivers would be willing swap pounds sterling for pounds per square inch, to ensure accuracy and well-maintained air lines.
Most motorists feel that 20p or 50p is a reasonable price to pay for reliable, accurate and clean airlines at a garage. However, if the price were to be £1, just one in eight men would be prepared to pay but almost a third of women think it a reasonable charge.
Until manufacturers provide more useful information, the IAM Trust’s advice is to buy a low-cost digital gauge and a 12-volt air pump, either separately or as one unit, and set the tyre pressures when they are cold, before the car is driven. In spite of improving accuracy, motorists just can’t rely on using filling station equipment to maintain accurate, safe and fuel-efficient tyre pressures.
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Media Contacts
Barry Walsh 020 8996 9776 barry.walsh@iamtrust.org.uk
Tim Shallcross 020 8996 9773 tim.shallcross@iamtrust.org.uk
Notes to Editors
The Tyre Gauge, Survey which includes testing of DIY pumps and gauges is available at www.iamtrust.org.uk
The Survey
The IAM Trust asked 500 motorists how often, and where, they checked tyre pressure.
How often?
- 18 per cent of men and 4 per cent of women do the recommended weekly check
- 37 per of men and 32 per cent of women check every month
- 13 per cent of men and 26 per cent of women rarely check, and 9 per cent of men and 20 per cent of women leave it until the car is serviced
- Drivers aged over 65, and those who are widowed, divorced or separated, are more likely to check their tyres monthly
- Drivers from the South-east are most likely to check; those from the East Midlands are least likely
- 84 per cent of men check the tyres themselves, compared to 43 per cent of women
- 10 per cent of men aged 17-24 let a woman do it for them
Where?
- 39 per cent of men and 32 per cent of women use their own pressure gauges
- 61 per cent of men and 67 per cent of women use a garage airline
- Drivers between the ages of 25-35, and those who live in London (94 per cent), are most likely to use filling station equipment
- 90 per cent of all drivers think garage equipment is ‘fairly’ or ‘very’ accurate
Charging?
- 71 per cent of motorists think it is a good idea to pay to use forecourt air lines, because it will ensure accuracy. The number is higher in Wales (82 per cent) than in London (54 per cent)
- Most motorists will pay 50 pence to use accurate equipment, but only 3 per cent are willing to pay more than £1
The IAM Trust also checked air pumps available on 45 filling station forecourts.
- The majority of pumps tested were new, digital units, and the gauges were accurate to within 5 per cent at 30psi – a significant improvement on a 2005 survey, when almost half the gauges were more than 5 per cent out
- Another change from 2005 is that most service stations now charge for the use of the pump – typically 20p for two minutes or 50p for three minutes.
- A major concern is that few pumps have charts showing the correct pressure for tyres on individual makes of car
A selection of DIY equipment that can be used to check tyres at home when they are cold was also assessed.
- Best buy is a digital gauge that is part of an electric pump, with a preset facility to inflate tyres automatically to a specified pressure. Prices are £15-£30 and the £15 type is a simple and economical way of keeping tyres correctly inflated
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