Auto Service World
Feature   March 1, 2007   by Guy Arbour

Yokohama unveils its new IceGuards

Do you remember driving through winter ten years ago, spinning wheels on ice in a snow storm or getting stuck in snow banks? These things don't happen to me anymore, and a good part of it comes from s...

Do you remember driving through winter ten years ago, spinning wheels on ice in a snow storm or getting stuck in snow banks? These things don’t happen to me anymore, and a good part of it comes from state of the art technology embedded in today’s winter tires.

First, you had the Bridgestone Blizzak defining new standards in winter driving, then came the Michelin X-Ice, which allowed your car to skate like Guy Lafleur on ice, but it may well be that Yokohama is now providing the industry with the next breakthrough: water film sucking technology.

On the day following Quebec’s first big January snowstorm, Yokohama Canada gathered a few press journalists at the fashionable Chteau Montebello testing range often used by LandRover to assess their vehicle’s handling. On this day, the press was to be given the chance to test how the Yokohama Geolander iTG072 and the IceGuard studless iG20 winter tires handle in such harsh winter driving conditions.

How do you grip in winter

One of the issues the new Yokohama tires are made to address is the factor that many believe brings down the tire friction coefficient when someone is driving in snowy-icy conditions: the thin water film that forms underneath the tire and the dangers this causes when driving in winter conditions. Under pressure, ice melts; but when that pressure is released, the water once again freezes. Over time, as the water film under the tire forms due to the application and then release of pressure, tire traction is lost — and that loss of traction is what diminishes driving control. So the question for any tire manufacturer becomes how to get this water away from underneath the tire so it does not freeze, thereby maintaining optimal traction in ice and snow and preserving drivability?

What Yokohama’s engineers discovered is for an average North American automobile, there is a danger zone between -6C and 0C, whenever the water film reaches a thickness of 10 micrometers or more. What the engineers came up with to tackle this danger zone is a new water absorbing tread compound, chalk-full of micro-bubbles and absorbent multilayered carbon contacts. These micro-bubbles use the tire’s contact pressure to suck in the water and away from the road surface. The multilayered carbon contacts and the carbon particles used in them have a capillary action that further drains the water away. As the tires spin, the micro bubbles and the absorbent carbon contacts work together to get rid of the water, preserving the traction of the tire in winter driving conditions.

Along with this technology, Yokohama has also put in a variety of new pattern and groove improvements to the tires, such as smart water flow grooves, central blocks, slush grooves, micro grooves and diagonal grooves. As well, a closer inspection of the tires reveals a grooves-in-grooves design that is to improve the shear response within the rubber matrix of the tire.

Taking the tires out for a spin

The Yokohama iG20 were fit onto new ABS-equipped Ford Fusions vehicles. The equivalent Yokohama tire for an SUV, the Geolandar i/T G072, was loaded onto a set of Ford Explorers. Five other industry reference, non-Yokohama winter tires were installed on identical vehicles which would be used as a comparison to the Yokohama tires.

As one may have expected, it turned out that the Yokohama iG20 behave incredibly well on the Fords Fusion, both on ice and on snow.

Things of most importance with winter tires are:

1 Ascending icy-snowy slope behaviour: good tires must adhere on slight uphill acceleration.

2 Descending slope handling and braking: good tires are expected to provide grip at decent downhill braking speed.

3 Turns on icy or snowy surfaces: this one’s more tricky and also depends on the car balance and ride control.

4 Braking distance on flat ice: silica additives provided a breakthrough in breaking in recent years.

5 Braking distance on deep snow: that’s where grooves and blocks come in action.

The Yokohama tires were certainly at least equivalent or superior to the other industry reference brands of tires that Yokohama went up against; and proving the worth of the extensive science and engineering that went into designing them.

The experience of the tires on the Ford Explorer SUVs was less obvious. These driving machines are so heavy, and their tires so big, that they climbed, braked, accelerated and turned in ways comparable to most of the brands they were tested against. But again there, the Yokohama Geolandar tires definitely stayed in the top-rank in terms of excellence of performance. Fine-tuning the minute differences, for SUV tires, would require perfectly controlled conditions, a bit more scientific instrumentation and probably more time than what we journalists had available to us that day.


Both tires will be available for next Winter in 51 sizes (13-18 inches) for the iceGUARD Studless iG20 (speed: Q, R&T), and in 24 sizes (15-17 inches) for the Geolandar i/T (speed: Q&R).

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