For Kumho’s Australian truck and commercial vehicle tyre manager Harvey Hawes, the Korean brand’s new KRT03 Longmark trailer tyre is perfectly suited to this country’s hugely demanding conditions, and he’s not shy about sharing his reasons why.
He starts by explaining that the combined effects of poor trailer axle alignment, inconsistent tyre pressure maintenance and marginal road conditions are well known for producing uneven tread wear and diagonal scuffing on trailer tyres in this country.
However, the new Longmark tyre has been developed specifically for Australian conditions with extensive input from Kumho Australia field managers directly into the tyre maker’s research and development facility in Korea and the results, he asserts, speak for themselves.
The key feature of the KRT03 is the use of a three-rib design with wider ribs that are more stable and rigid than those found on trailer tyres using a four or five rib design.
Accordingly, the tyre resists diagonal scuffing and is able to handle a mix of both on and off-road conditions, performing equally well on paved surfaces at constant high speed, in winding conditions or on gravel and dirt surfaces.
“We came at the problems (of diagonal wear and scuffing) from a very different angle,” Harvey said, “by basing the KRT03 on the successful Kumho 956 steer tyre and we are delighted with the feedback from operators all over Australia, with many telling us they’re getting much longer tyre life and reduced diagonal wear or scuffing.
“With the three rib design it means the tyre tread distortion that often occurs with badly aligned trailer wheels is minimised or prevented entirely,” he remarked.
“By reducing the number of ribs, making each one wider and more rigid, Kumho has eliminated this problem without compromising grip and braking performance as well as greatly extending tyre life.
“With this design operators are getting the full tread life from tyres instead of having to throw tyres away at 50 or 60 percent tread wear because of deep diagonal wear across a small portion of the tyre,” Harvey added.
Kumho has also employed a 13 mm tread depth on the KRT03 instead of the usual 15 mm used on most trailer tyres to further aid the stability and rigidity of the tyre ribs.
“The deeper tread depth on most tyres creates more distortion and means the tyre runs hotter, however reducing the depth by two millimetres creates better stability, cooler running and ultimately much longer tyre life, again without compromising grip.”
Harvey Hawes also pointed to the fact that many transport operators unfortunately pay greater attention to steer and drive tyres than to trailer tyres. He insists, however, that trailer tyres are every bit as important and make up the majority of rubber on a semi-trailer or B-Double combination.
“On a conventional 22 tyre semi, trailer tyres make up 55 percent of the mix and on a B-Double they comprise 70 percent of the tyres on the vehicle, so they are not only vital to the truck’s efficient operation, they are also a major cost,” he explained.
Furthermore, the KRT03 design also includes stone ejectors in all grooves to maximise the clearing of stones from the tread as well as tread nib division for more even load distribution and better wear performance.
The Kumho KRT03 has a 16-ply rating with a load index rating of 148/145L in the 11R22.5 size. The tyre has a carrying capacity of 3000 kg in single and 2725 kg in dual fitment.
Finally, Kumho is certainly no small player in the global tyre industry. The company produces more than 65 million tyres annually with a massive research and development programme comprising more than 600 research personnel and 300 testing machines at proving grounds in South Korea, China, Europe and North America.