Higher cost of raw materials and post-Brexit dip in exchange rates have helped overcome prejudices and regenerate interest in remoulded truck tyres, John Lewis discovers. 

Retreaded truck tyres are enjoying a marketplace boost after several years in the doldrums. The reasons for the upswing in demand are not hard to fathom, according to Bridgestone retread development manager Terry Salter (pictured).

Much of it is due to the fact that new truck tyre prices have been hit by a double whammy. 

A very high percentage of new tyres are imported. As a consequence, the 12% fall in the value of sterling against the euro and the 15% fall in its value against the dollar in the wake of last year’s vote in favour of Brexit has made them more expensive. 

Hence the cheap-and-cheerful new truck tyres, often bearing unfamiliar brands, that have been shipped in from the Far East and that have competed with retreads on price are no longer as appealing to operators as they once were.

To that can be added a sharp rise in the cost of many of the raw materials new tyres contain with steel and natural rubber leading the charge, although oil prices were trending downwards at the time of writing.

Significant volumes of retreads are British-made. Bridgestone makes them in a factory in Bourne, Lincolnshire, which has enjoyed around £500,000 of investment over the past 18 months. 

“We’re expecting to produce more than 60,000 this year but we may do in excess of that,” Salter says. The plant has the capacity to turn out up to 80,000.

No matter where they are made, retreads have the further advantage that they consume fewer raw materials to construct than their new counterparts. 

“A new truck tyre weighs 65kg to 70kg but a retread only needs 20kg of fresh steel, natural rubber and so on before it can go back into service,” Salter says.

What is more, while it takes 83 litres of oil to make a new tyre it only takes 26 litres to make a truck retread.

Net result of all the foregoing? A quality retread is typically 30% cheaper than its new equivalent and should last just as long.

Recycling as much material as possible makes for a positive environmental story for fleets eager to shrink their carbon footprint. In this context it is worth noting that CO2 emissions generated by retread manufacturing are a third  lower than those created when new tyres are produced.

Eager to hammer home its environmental credentials, the Bourne plant ensures that all the rubber fragments generated during retread production end up in a huge bag that sits on a vibrating plate that keeps shaking the contents down. After some 14 hours the bag is full and is then shipped off to firms that make playgrounds for children. They use the rubber to create soft, child-friendly surfaces.

Bourne makes two types of retread – hot cure and pre-cure – and its output is split roughly 50/50 between them.

“Hot cure retreads look better cosmetically than pre-cure and are a bit cheaper, but pre-cures last longer because of the density of the tread rubber,” Salter observes. 

The first part of the production process is similar for both and involves tyres that have been collected from fleets and inspected prior to arrival at the factory. While roughly three-quarters of its output is based on Bridgestone or Firestone tyres, Bourne is willing to work on products from other premium brands. 

Once they arrive, the tyres are buffed to remove the old tread rubber, examined for damage and the presence of foreign bodies which are removed, and repaired if needs be with strong reinforcing patches. 

“Around 40% of them undergo this type of repair,” says Salter.

The tyres undergo a constant inspection process as they pass through the factory which involves, among other things, something called shearography.

This testing process involves photographing the tyre and then putting it into a vacuum where another set of pictures is taken.

The two sets are compared to see if any part of the tyre’s structure is coming loose so appropriate action can be taken.

With a hot cure tyre, fresh rubber is applied to the circumference of the shaved casing which then goes into a large, enclosed mould which presses the tread pattern into place. It does so at a temperature of 155 degrees C which is maintained for more than an hour and a half.

Pre-cure production involves applying pre-formed treads to the prepared casings with a £250,000-plus extruder/builder. “It can turn out up to 15 tyres an hour and with a greater level of accuracy than the equipment we used to use,” says Salter.

The pre-cure tyre goes into a rubber bag, all the air is sucked out of the bag, and the tyre is cooked in an oven at 115 degrees C for just over two hours.

The UK has traditionally been a hot cure market, says Salter, but there is a gradual drift in favour of pre-cure. 

Bridgestone is in a good position to take advantage of any such trend thanks to its acquisition of pre-cure specialist Bandag’s global retreading operation just over a decade ago. It makes Bandag retreads in Bourne.

If cost is a key decider for a fleet then it is worth noting that the Bandag catalogue encompasses a second-string range under the Protread banner. The tread is shallower and less-expensive than the one employed on the mainstream Bandag offering and lower-grade, but still perfectly acceptable casings are used, says Salter.

Retreads such as those made by Bridgestone are dependable he contends and enjoy a good safety record. Prejudices still have to be combated however, he admits.

“A lot of operators don’t like to use them on steer axles although there are exceptions,” he says. 

Refuse collection fleets can be happy to employ them in that role, for example. Retreads are ideal for their typically-low-speed stop-start duty cycles and the risk that they will be damaged while a load is being discharged means that fitting them can be a more cost-effective bet than investing in pricey new rubber.

Bourne’s most popular size remains 295/80 R22.5 but Salter suspects it will not be for much longer given the changing requirements of fleet users. 

“The 385/65 and 275/70 are getting a lot closer and really it’s going to be between these three,” he observes.

When they arrive at Bourne each casing is allocated a job card. However, this paper-based system is being abandoned in favour of something called BASys.

Cloud-based, and part of Bridgestone’s Total Tyre Care programme, BASys allows the tyre destined for retreading to be followed all the way through the production process from when it is taken off the truck to when it goes back into service. 

Their ability to be retreaded means that quality truck tyres have an inherent value; but that value will only be realised if they are correctly maintained, stresses Bridgestone. 

That means checking pressures regularly to ensure they are neither over- nor under-inflated and emphasising to drivers the importance of including tyres in their daily walk-around checks.

Spotting a nail sticking out of a tread and reporting it in good time so that action can be taken could mean the tyre’s casing can be salvaged for re-use rather than damaged beyond repair; and a sudden blow-out avoided.