Green choice

Lowering CO2 emissions and reducing fuel consumption are two of the major aims of fleet managers today.

One way to tackle these issues is by using eco-friendly tyres.

Manufacturers have been developing eco-friendly tyres for more than two decades, all with the aim of reducing rolling resistance while not compromising on quality or safety.

This applies in particular to the effect of short braking distances on dry and wet roads, where low rolling resistance has historically proved problematic.

But, as tyres account for 20% of fuel consumption, they are seen as being an area of hidden costs, as well as a way of making fleets greener and cheaper.

Steve Dolby, product marketing manager at Michelin, says: “The most recent tests, carried out by TUV in 2009, show that our eco-tyre gives an average gain of 2.5% against premium tyres.

"Of course, there’s also rising fuel costs and tyre life to consider, but we found that the tyres would pay for themselves over their lifespan.”

Michelin estimates that, assuming an annual mileage of 12,500 miles at 30mpg, a fleet of 100 cars could save 14 tonnes of CO2 and £7,400 in fuel costs.

“That’s assuming fuel prices are £1.30 a litre, which is what they are about now,” says Dolby.

Meanwhile, Continental is about to launch a new tyre that can cut fuel consumption by 3% compared with standard tyres.

Due in spring, the ContiEcoContact 5 has seen rolling resistance reduced by a fifth compared to its predecessor, with mileage performance raised by 12%.

Tread carefully

A vehicle’s tyres provide the vital grip for braking and control of steering, so maintaining them is of the utmost importance.

One of the crucial factors in the condition of tyres is their tread depth, which is essential to
stopping safely.

The legal minimum requirement is 1.6mm across the central three-quarters of the tyre. Break it and the driver faces three points and a £2,500 fine per tyre.

However, Bridgestone recommends changing tyres at 3mm.

Andy Dingley, communications manager at Bridgestone, says: “There are significant performance differences in tyres with 1.6mm of tread depth and those with 3mm.

“The less tread depth, the greater the stopping distance, meaning the impact this can have on the likelihood of an accident is potentially huge.”

Tread patterns are designed to evacuate water so the tyre contact patch can maintain grip. Worn tread reduces water dispersal, reducing braking efficiency.

However, fleets need to weigh up the claimed safety benefits against the higher cost – and this depends on the replacement cycle.

New tyres have a tread depth of 8mm.

Taking an average of 28,000 miles before reaching the legal limit, a car will be on its second set of tyres at 60,000 miles irrespective of whether its policy is to change at 1.6mm or 3mm.

However, if it keeps cars for 80,000 miles, it will be on its third set of tyres if it replaces at 3mm, its second if it replaces at 1.6mm.

At £85 per tyre, this means a rise in cost of £340 for one car. Multiply this up across a 100-strong fleet, and the cost will be £34,000.

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