Michelin Agilis — April 2008

Date: Monday, April 07, 2008

They may be round, black and visually dull as dishwater, but make no mistake; tyres are one of the most fundamental components of any vehicle.

Just think about it for a moment. If the tyres are crap it doesn't matter how much horsepower and torque an engine is putting out or how sophisticated the disc brakes, ABS and suspension set-up are. The result will be poor grip, inability to transfer torque to the road, overlong stopping distances and rubbish handling.

The only things keeping a light commercial — or car for that matter — on the road and facing in the right direction at any given time are four contact patches the size of an adult's hand palm. It's a chilling thought which most drivers would rather not consider.

And believe it or not tyres play a significant part in fuel consumption. Just try running on under-inflated tyres for a while and watch the fuel gauge head towards Empty quicker than normal.

What Van? remains impressed with the current Michelin Agilis line-up of LCV tyres, but as of this month owners of vans between 2.8 and 3.5 tonnes will have access to a brand new range simply called Agilis and replacing the old 61, 81 and 101. The 41 and 51, aimed at smaller vans, will be replaced in the next two or three years.

Next Generation

Michelin has taken LCV tyre design to the next level using experience garnered from the original Agilis range being used in real-world conditions and combined this with all the latest pertinent developments in passenger car and truck tyre design.

The result, Michelin claims (and it has independent test data to back it up), are tyres which have increased grip, robustness and longevity as well as providing a reduction in fuel consumption and hence lower CO2 emissions.

Rolling Resistance

Michelin bused in journalists from across Europe to its enormous test facility near Almeria in south east Spain to demonstrate just how effective the new Agilis tyres really are.

First stop was a test designed to show the improvement in rolling resistance, a significant factor in reducing fuel consumption. It is reckoned that generally speaking one tank of fuel in five is used up simply to overcome the rolling resistance of the tyres.

Two identical Fiat Ducato vans, each carrying 1,000kg of payload, were released from the top of a shallow incline and allowed to roll down under their own steam. They reached around 20kph before ending up on a flat stretch of road and were then freewheeled until stationary.

The van fitted with the new Agilis tyres rolled an average of 18m further than the one riding on their predecessors. A pretty graphic demonstration.

Fuel Saving

Put into mathematical terms this represents a saving of 0.2 litres of fuel per 100km (62 miles). This may not sound like a great deal, but it means, for example, that after 85,000km (52,817 miles) one of the tyres has paid for itself.

A reduction in fuel consumption naturally leads to lower CO2 emissions — so beloved of governments across Europe as an excuse for extracting more money from taxpayers. Working out the figures translates to an improvement of 4.0g/km which could be enough to bring a vehicle into a lower CO2 tax bracket.

Robustness

It's all well and good developing a tyre with reduced rolling resistance, but the robustness and longevity of the tyre must not be compromised. It's a delicate balancing act, but Michelin seems to have pulled it off.

It claims that the new Agilis is good for an average of 85,000km which is an improvement of 20 per cent over the tyre it replaces.

Tread pattern, sidewall and internal structure all play their part and Michelin has once again payed particular attention to protecting the sidewalls from damage. After all its not unknown for a van driver to run a tyre against a high kerb or even mount the pavement.

As with its predecessor, the new Agilis features a series of raised blocks (6mm deep) around the sidewall and the rubber has been strengthened so that it loses less mass. A rigourous testing regime was developed that entailed running the tyre against a kerb continuously for 1.2km. This equates to about two years of use and the blocks lose about only 1mm of their depth.

As a way of showing just how durable the new Agilis really is Michelin let us lose on what was basically a gravel rally special stage leading up into the foothills of the Sierra Navada mountains. Apart from being fun — we were driving a VW Crafter (rear-wheel drive) with the traction control switched off — the tyres coped with consummate ease and the new tread pattern did a sterling job of ejecting small stones and gravel. There were just a couple stuck in each tyre once we had finished the run.

Safety

Speaking of the tread pattern, it obviously plays a major part in determining the amount of grip, and therefore of safety, provided by a tyre and it's very different to that of its predecessor.

It's much more truck-like than it used to be with larger blocks and wide trenches for improved water egress. Improved rubber compounds mean there is now less deformation under load to the blocks which helps to keep the temperature down and improve performance; and helping to reduce fuel consumption.

The new Agilis also incorporates the latest Durable Contact Patch Technology innovations developed through Michelin's experience with truck tyres. The contact patch is now much squarer (bottom pic) than on the previous Agilis tyres.

Braking

With the performance of vans ever rising it's of paramount importance that braking distances are kept to a minimum, especially in the wet. Even when partially worn the new Agilis shortens wet-road braking distances by three metres when compared to its predecessor. And this is without the aid of ABS and ESP.

The compound of the tyre is designed to retain its suppleness for a longer period of time. Called the Durable Security Compound, it was initially developed for passenger car tyres.

Handling

The end result of all this technology is a tyre which also improves a van's handling. Turn-in is sharper (the speed at which the front wheels react to steering inputs), there's better balance at the rear and the handling of weight transference is improved — through a series of cones, for example.

Unfortunately we were unable to test this for ourselves as the wet steering pad had suffered from a diesel leak from the water tanker before we arrived and had turned into an ice rink — diesel and water are a lethal combination.

Speaking to other journalists, however, who had managed to try the test pre diesel leak — two vans, one fitted with the new Agilis, the other with the previous generation — they seemed pretty convinced that the new tyres were a definite improvement in terms of grip and handling.

VERDICT

 
Michelin has to be congratulated on this new Agilis range of van tyres. Improved fuel consumption, leading to a reduction in CO2 emissions, increased longevity, shorter braking distances and better handling all add up to a major step forwards in tyre technology. The new Agilis ticks all the right boxes.



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