Better tyres cut costs, boost safety

Tyred out!

They’re often small, round and usually black – and they’re essential to efficient and safe operations.

Ruari McCallion looks at lift truck tyres.

The physical connection between a Formula One Grand Prix racing car and the track on which it runs is four small patches of rubber, each about the size of a large business envelope.

They are the contact points of the tyres. Ask a racing engineer about their role and be prepared for a potentially long and detailed explanation of the importance of grip, different compounds, load at speed, under braking and cornering forces, and the effect of side winds and surface water. Aerodynamics and engines are important but the tyres are vital.

What is the connection with lift trucks? Again, the point of contact with the ground is four small patches of rubber. Racing tyres can be changed, depending on conditions, with special compounds and tread patterns to cope with hot tarmac, light rain or monsoon conditions. Lift trucks have no such luxuries. A single set of tyres has to cope with heavy loads, no loads, slippery surfaces and smooth concrete, and move from warehouse interiors to outside conditions, whatever they are. They could be regarded as the first line of safety in operations. Indeed, one manufacturer ran an advertising campaign a few years ago which proclaimed that ‘a driver has five safety belts”. We make four of them.

Buying cheaper = false economy

Tight economic conditions and competitive pressures mean that operators will look everywhere for opportunities to save costs and it is tempting to go for cheaper options, wherever they can be found. That could be a mistake and, in the case of tyres, quite an expensive one.

Cheaper tyres often do not perform as well as apparently more expensive alternatives. They may wear out faster and they may have less grip, and the latter could lead to serious workplace accidents. As lift trucks are involved in a quarter of all workplace accidents, there is absolutely no justification for running an increased risk.

Total cost of ownership is the right basis for purchasing decisions, rather than front-end ticket price. A lift truck fleet represents a significant investment but it is after purchase that the true costs emerge, in terms of reliability, maintenance and replacement. In the case of solid industrial tyres, the total cost of ownership will be determined by mileage, fuel consumption, energy consumption, downtime costs and service. A long-lasting tyre reduces downtime and fitting costs, minimises wasted rubber on the whole tyre, not just the tread rubber, and also has an impact on CO2 emissions.

“As lift trucks are involved in a quarter of all workplace accidents, there is absolutely no justification for running an increased risk.”

Testing time

Fleet operators’ assessment of tyre wear is often based on a combination of own experience, assurances from suppliers and hearsay.

None of these is entirely satisfactory; dispassionate testing is needed and, to this end, industrial tyre manufacturer Trelleborg Wheel Systems set up a test with TUV SUD Automotive, the German certification body, with the intention of analysing and evaluating tread wear of its own Elite XP LOC solid tyre, and to compare it with another established industry model. The intention of the exercise was to measure tread wear in simulated heavy operational conditions. The factors measured were weight loss, which would give the project information on the amount of rubber used. Tread depth was also measured at 16 points on the tyre, at four points across the width of the tread at 90 degree intervals.

The test was conducted in March 2011 at Istituto Sperimentale Auto e Motori S.p.A. (ISAM) in Anagni, Italy. TUV SUD bought the tyres on the open market and the electric counterbalance lift truck used carried a 1730kg load, around 70% of its maximum capacity of 2500kg. The test track measured 320m and was conducted in accordance with ISO10844 Annex A, which covers texture depth of 1.8mm. Speed was kept constant and equal for both brands by limiting accelerator pedal travel and adapting it to the tyres’ circumference.

The trucks in the test were run for 38.3km in total, with drivers and direction of travel changed every 20 laps. The Trelleborg Elite XP showed a weight loss of 900g on the front tyres, and 250g for the rears.

Watch out for wear

What the test illustrated was that even the most resilient tyres perhaps wear out at a rate operators do not fully appreciate. It also strongly suggests that premium tyres are, in fact, likely to be the lower-cost choice for full cost of ownership – the comparator tyres wore even faster. In order to get the best out of the truck fl eet, paying attention to the humble doughnuts of rubber at each corner can yield dividends in costs of operation, including energy use. In a challenging and competitive market, any opportunity to save money should not be ignored.