Metzeler Sportec M5 Interact technical

By Kevin Ash - 21/03/2011

The key to Metzeler‘s Interact technology lies in the 120 or so steel chords which run around the tyre‘s carcass.

These are designed to help the tyre maintain its shape at speed and help support the weight it‘s carrying, and they run parallel to the wheel‘s rims, which is why this kind of tyre is known as a zero degree belted radial.

They still have to allow the tyre to deflect though, so it can present a flat contact patch to the road then spring out again as it rolls around. A very stiff tyre will deflect little under load and so have only a small contact patch, but its wear rate will be good as the rubber is not being flexed much - at the contact patch it‘s not rubbing against the road a great deal. Flexible tyres provide more grip by squashing down and increasing the contact patch size, but the bike‘s stability suffers and the wear rate is greater.

Metzeler has varied the tension in the steel chords to change the flexibility of the tyre as it leans. In the centre, the chords are tighter and therefore stiffer, preventing so much deformation of the tyre. This gives it better wear characteristics when the bike is upright, and good stability under braking and acceleration. At mid lean the chords have less tension, so more rubber is in contact with the road and grip is good, especially useful in the wet. At the edge of the tyre the chords‘ tension is high again, improving feel and stability at the very edge of grip.

While the tyre also has two compounds - a stickier one at the sides and a harder, better wearing one in the centre, varying the tension in the chords gives it more progressive changes as it leans rather than simply switching from one compound to the other.

This chord tension change also means the increase in contact patch comes from increasing its width rather than length, which keeps it cooler (the centre of a long contact patch has to deflect further than a shorter one) which in turn means better wear.

The tyre‘s tread pattern is shaped like the Greek π symbol, which is cool for mathematicians, but it‘s useful too in that the central grooves run along the line of the tyre, helping stability, while the outer ones point to the side, helping to pump water away in the wet. It‘s designed so that there are always two grooves in contact with the road, for consistent water dispersal

Back to Metzeler Sportec M5 report

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