Cooper Tires AT3: outback development testing

IT’S BLOODY hot. Even in the shade of the Cameron Corner Store’s veranda area, this February day’s heat is hard to escape.

This short respite for lunch interrupts what has been a rugged four days of punishment for not only drivers and vehicles but, most importantly, for the all-new Cooper Tires AT3 tyre. In fact, that should be plural. Responding to consumer demand – and in a claimed market first – Cooper Tires is releasing three variants of the AT3. Yep, off-road tourers are seriously over-indulged by the US tyre giant.

“Research has revealed that consumer preferences for all-terrain tyres vary with the size of the tyre,” says Andrew Collings, Exclusive Tyres’ marketing manager (Exclusive is Cooper Tires’ Australian distributor). “After extensive research and testing, Cooper decided to offer the AT3 in a lighter duty P-metric and heavier duty Light Truck configuration, depending on the consumer’s need.

“The new AT3 line includes three distinct all-season, all-terrain configurations; for SUVs (AT34S), utes and heavy-duty 4WDs (AT3 LT and AT3 XLT).”

The AT3 LT offers what Cooper Tires dubs Durable-Tread Technology, where its new coupled silica tread compound – designed to optimise resistance to cuts and chips, as well as increase traction and extend the life of the tyre’s tread – is combined with the tyre’s particular tread pattern.

The AT3 XLT adds “rugged traction shoulders” (read: sidebiters) in some larger sizes for extra grip in extreme off-road terrain such as mud-filled ruts, as well as extra puncture and staking resistance.

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Brisbane-based Exclusive Tyres has brought a big team out here that includes two Cooper Tire & Rubber Company’s US engineers – Ken Reuille, a regular visitor to Oz, and first-timer Martin Kaufman – to see if this latest incarnation of one of the company’s most popular hoops is a step up from the previous-gen AT3.

The route encompasses a 985km sealed road run to Thargomindah, then looping through Innamincka, Cameron Corner, Bulloo Downs and Tibooburra – and will, by week’s end, have totalled just over 4000km. It means the tyres cop a stern test in country they’ll be used in.

The Reasons Why

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ACCORDING to Cooper Tires’ Ken Reuille, these outback test trips are highly valued by the US company and have been so for many years.

“Cooper Tire Rubber Company has been testing tread designs, carcass constructions and compounds on RLT products in the outback for about 15 years now,” Ken says. “Starting with the development of the original Discoverer ST, followed by the S/T Maxx, the STT Pro, and most recently the new AT3 available this year.”

The tyres are developed and then tested extensively at Cooper Tires’ US HQ, both in-lab and out on test tracks, but it is the product validation testing – a final tick of approval, if you will – that takes place in Australia, and on these tracks with their unique (read: rough, rugged and uncompromising) surfaces that offers the final shakedown of the product.

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“It would be extremely difficult to replicate in the US, the climate, varied terrain, and diverse road surfaces present in the outback,” Ken says. “Testing in the outback has provided us with meaningful information that has allowed us to optimise the tyre’s tread pattern.

“For example, we added a raised rubber pad in the tread design of the STT Pro to aid in dislodging stones, and made changes to the shoulder siping of the new AT3 to minimise chipping, as a direct result of our outback testing.”

This validation of a tyre’s strength and durability, in regards to seeking all advantages in a competitive retail market, is something that is invaluable. And it works both ways, in terms of the opposing markets for the US tyre giant.

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“Australian customers of our products can have confidence that they have been tested and proven in the outback,” Ken affirms. “While our US customers know that if our products have been vetted in the outback, they will perform well when exposed to likely much less severe service conditions in the US.”

Hard Work Behind the Scenes

BY THE TIME the glossy brochures are printed and on display – and tyres have landed in the retail outlets – all the hard work has been done, with this development trip the perfect example.

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By spending many hours in testing, the brand can be confident the product will be more than up to the task after being hammered through the outback. This doesn’t mean this trip is just about punishing tyres and seeing if they ‘survive’, there’s a little bit more to it than that.

For this week of Corner Country testing, the team at Exclusive Tyres has set-up a straightforward and very effective testing protocol: one Toyota Land Cruiser LC 79 Troopy will be fitted with the prototype AT3 LT, another with the previous-gen AT3, and there will be two ‘control’ Troopies, each fitted with a competitor’s equivalent-spec tyre.

As well, the new AT3 XLT (a slightly chunkier style of AT3 with beefier traction shoulders down the sides) is fitted to the Cooper Tires Ranger and Prado. The drivers will be swapping vehicles each day – and swapping notes – to help determine the extent of the improvements designed into the new tyre.

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Things like ride, handling, how the steering is affected, how the tyre reacts (and drives) over different terrain, how/if the tyres are chipping (one of the main things addressed with this latest incarnation of the AT3 design); the week will see us cover everything from smooth, graded dirt to tracks covered in stones the size of a large avocado. All of the drivers on this trip are experienced off-road tourers, and the combined notes and observations will help form a firm view on the new tyres’ performance.

For those who are after a little more science to back-up the opinions, there are regular tread checks (for tears, slices, etc.), tyre temperature checks, and tyre air pressure observations throughout each day.

“The most important part about tyre evaluation is consistency,” says Andrew Collings, also one of the drivers on this trip. “We need to ensure all tyres – Cooper and the competitors’ products – remain at evaluation pressures for the whole trip.

"By doing this, the variables are more focused on what we intend to evaluate. We also watch temperature to ensure the pressures we have set-up in all tyres are not increasing by more than four to five psi from cold. We would see this increase as normal and outside this psi increase it may indicate that the tyre sidewall-flex is building heat in the tyre, and therefore the load or speed needs to be adjusted so the tyre performance is not affected.”

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The testers keep an eye out for an over-average temperature spike; increasing the tyre’s pressure alleviates the heat build-up, thus ensuring the tyre will stay within the testing protocols. A hot tyre can also cause deterioration in the carcass and lead to failure, which is the last thing you want when travelling through remote areas.

What Goes on Tour

FOR EXCLUSIVE Tyres, local tyre testing is a boon. Exclusive promotes this Australian testing heavily in its marketing and retail outlets and backs it up with first-hand experience during these weeks away, so Aussie customers know they’re paying their hard-earned for a tyre that is outback-proven. This confidence is reflected in mileage warranties of 80,000km for the heavy-duty, light truck tyre and 70,000km for the light-duty P-metric tyre.

Of course, this isn’t the only test of the tyres; by the time they lob Down Under, they’ve already undergone many hours and been driven on many different terrain types, as Andrew Collings explains.

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“When we get the tyres to test,” he says. “We know they have already gone through a variety of rigorous tests looking at tread designs, the carcass and compounds, as well as extreme real-life testing at their purpose-built 1000-acre tyre and vehicle test track in Pearsall, Texas, offering both on- and off-road testing facilities.”

It’s a bloody busy week out here; as much as where we are is spectacular in terms of a destination, it’s all business each day, with plenty of driving over varied terrain, accompanied by numerous stops to check the aforementioned pressures, temperatures and the tyres’ overall condition in terms of chipping, slices, etc.

It is not until the fourth day I get in a Troopy shod with the all-new AT3 LT. Driving the two control Troopys with the competitor rubber onboard was followed by a spin in the vehicle with the previous-gen AT3. In other words, the perfect scenario in regards to seeing how much improvement there has been between the two tyres.

Of course, it’s easy to think something newer simply has to be better, but that was never the case here. Over the course of the week, as I had progressed through different vehicles (with their different tyres) I noticed the previous-gen AT3 had been a step up from the two competitor tyres (one of these was, in fact, seriously scary on rock-strewn tracks) and this new model offered even more ‘track feel’.

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With a lot of the tracks we drove being the classic loose-over-hard (i.e. small/large rocks or sand/dirt over a solid base) surface, allowing for plenty of intended (and unintended) ‘drifting’ in and out of corners.

The new AT3 LT was brilliant at cutting through that loose and unstable top layer and biting into the solid and more tractive base, with the result a more direct and confident feel when steering, as well as all-round stability.

A part of this could be the addition of ‘stone-ejector ledges’, located at the bottom of the tyre groove channels, to the new AT3. These are designed to shift rocks/pebbles, etc., out of the tread and away from the tyre, keeping the tread open/clear and thus getting maximum tread surface to bite into the track surface.

The tyres were checked daily for chipping to see if the new chip-resistant compound was doing its job, and even by this late stage – and after plenty of serious punishment – the new rubber was holding up well.

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One of the other things Ken mentioned was Cooper Tires endeavouring to reduce tyre noise in the new AT3, with the introduction of what the company calls Whisper Grooves, with the result being a claimed 20 per cent reduction in tyre noise.

Again swapping between the two generations of AT3 – and taking into account the varying ‘quality’ and type of road-seal used – the new model seemed slightly quieter. I wouldn’t bet my life on it being hugely different in regards to the volume of tyre-noise transferred in-cabin (we were in Troopys, remember, which ain’t the quietest rigs), but it seemed quieter, just the same.

Cooper AT3 LT 265/70R17: First Impressions

BACK in the day, it was cross-ply Bridgestone “Jeep Service” in 750x16 that adorned many serious 4x4s. And on 40 Series Land Cruisers, they were often fitted to stock safety rims that had been split and widened (some would say made unsafe) by welding in a two-inch band. However, tyres and wheels have progressed a wee bit since then.

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Having worn out many different types and brands of tyres, I was happy to fit and try the new Cooper AT3 LT. The current vehicle is a TDV6 Amarok but fitted with earlier VW OE 17-inch rims in place of the original 18-inch. The Cooper AT3 tyres are 265/70 in Light Truck (LT) construction.

At a glance, the first noticeable visual feature of the new Cooper AT3 LT is the chunkier tread edge, with every other tread block staggered, and the patterned sidewall treatment. They look like they’ll bite.

The first noticeable performance feature is the on-road quietness. After several thousand kilometres dragging a 2.5-tonne trailer on mostly black top, there is no heel and towing, and they remain quiet. Off-road forays thus far include plenty of beach driving and some easy tracks in the Myall Coast hinterland.

The chunkier edge and slightly squarer profile should (theoretically) take the edge off the AT3’s performance in sand compared to its predecessor, but at 18psi it floated confidently over the soft sand of Bennetts Beach. The 550Nm of the Amarok might help there, of course.

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A “toughness” test will come in late September when the Amarok will suffer the brutal rocks of the Barrier Ranges as a support vehicle for press coverage of the Outback Challenge. Standby for that report.

When unladen, experimenting with pressures – about 32psi for dirt roads and 35psi on sealed surfaces – seems the best compromise, with pressure increased closer to 40psi with a load and the trailer attached.

There is a need to note that any judgement of 4x4 tyre performance in rough, uneven terrain has to be affected by vehicle dynamics. Whereas older 4x4s without traction aids rely almost solely on tyres being in firm contact with the ground and having good traction characteristics, current generations of 4x4 vehicle traction and stability control might mask any tyre traction shortcomings. –Norm Needham

The End Game

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BEING able to go behind the scenes and see just how much work Cooper Tires and Exclusive Tyres put into ensuring the product performs how it was designed to – and witnessing the passion all members of the team have for the minutia of tyre design and performance – was an eye-opener.

It really did make me, as an example of their core buyer market, appreciate just how much is involved in a piece of essential equipment that every off-road tourer puts their faith – and family’s safety – in when they head out bush.

Of course, there’s no perfect test that can prove 100 per cent how capable an off-road tyre is. There will always be the variant of individual drivers and their skills, as well as where they drive, but this week in the Corner Country, punishing the Cooper Tires AT3 without fear nor favour, offered a near-ultimate endorsement of the US brand’s dedication to continuing to improve on what is already regarded as top-notch off-road rubber.