SPOT UNEVEN WEAR WITH VAI
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Continental has developed a simple way of highlighting premature and uneven wear on steer-axle tyres caused by excessive negative or positive camber and toe-in/out.
Its Visual Alignment Indicator (VAI) ensures that premature tread wear (and greater fuel consumption due to the associated increased rolling resistance) caused by poor wheel alignment on trucks and trailers can be quickly identified “without complex electronic measurements”.
The VAI consists of pairs of sipes positioned in the tread at five measuring points around the tyre shoulder. After just a few thousand kilometres, operators can simply compare the stripe-like indicators, which are between one and four millimetres deep, to check whether the wear on both sides of the shoulder matches the wheel on the opposite side of the axle. Even users without specialist knowledge can quickly recognise incorrect wheel alignment from the indicators.
VAI has been successfully used in the US for many years and is now available in Europe. Continental says that in future it will provide VAI as standard, at no extra cost, on steer-axle tyres in the new long-distance class 2+ range in sizes 315/70 R 22.5 (standard and XL versions) and 355/50 R 22.5 wide steer products. Whether VAI will feature on other tyres is unclear, although Roger Sanders, Continental’s UK general manager technical services, says: “In the clear majority of times irregular wear is on the steer-axle, so the validity of VAI is more critical on steer-axle applications. And as most tyres tend to be shrouded by the wheel arch, with VAI you can quickly tell, by seeing the number of bars, how much of the outer edge has worn.”
▲ VAI provides quick visual check on steer-axle alignment – so uneven wear is easy to spot