Size matters in super-efficient truck tyres

A significant shift in buying patterns among UK truck operators, away from traditional 295/80 tyres in favour of 315/70s, continues to gather pace in 2016.

For many years, the top-selling truck tyre size in the UK has been the 295/80 R 22.5. This size of tyre features a nominal section width of 295mm with an “aspect ratio” of 80 per cent on a 22.5-inch diameter rim.

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Three years ago these 295/80 R22.5 tyres were estimated to account for 25 per cent of the UK’s truck and bus tyre replacement market. But in 2014 a pronounced swing towards 315/70s began, both in the original equipment and replacement sectors of the market, despite the wider tyre costing more.

Guy Heywood, Michelin Tyre Commercial Director in the UK and Ireland, said, “More and more operators are realising that moving to 315/70 tyres can reduce their running costs and open access to the very latest generations of products, which tend to be developed in this size first due to its popularity across Europe. Our own surveys, and trials we’ve carried out in conjunction with truck manufacturers, have shown the benefits offered by 315/70 tyres – particularly in terms of fuel efficiency and tyre longevity. 

Now operators are experiencing these benefits in their own fleets too. It’s driving one of the most notable changes in tyre- buying habits we’ve seen this side of the millennium.”

John Comer, Volvo Group UK Truck Product Manager, explained that of all the Volvo tractive units on 22.5-inch wheels sold in the UK in 2014, 48 per cent were specified on 315/70 tyres, compared to 30 per cent on 295/80s.

Other truck-makers’ experiences support this trend. DAF Trucks, for example, switched from 295/80 to 315/70 as its standard tyre size when it introduced its Euro VI range. The main reason for this switch was to allow for the extra front axle loading added by Euro VI exhaust after-treatment kits. A steer axle shod with 295/80s is limited to a 7.1 tonnes plate in the UK whereas the same axle on 315/70s can go to 7.5 tonnes.

Meanwhile, Goodyear claims to be the first truck tyre-maker with a completely new steer-axle size: 375/45 R22.5. The new specification is designed to help reduce chassis height on tractor units pulling high-volume semi-trailers, with load volumes greater than 100 cubic metres, all while remaining within an overall vehicle height limit of four metres.