Triple Compound is the right Mix

The creation of an optimal rubber formula is a science in itself. Nobby Nic, Schwalbe’s new MTB competition tire, is the first ever to have a triple compound. Why Schwalbe (Reichshof-Wehnrath) developed this three-fold combination and why each mixture is a compromise between rolling resistance and grip, was explained in an interview with former MTB World Cup rider and Schwalbe tire developer Markus Hachmeyer.

Question: As clearly demonstrated in Formula 1: Why is it so difficult to find the optimum tire compound?
Markus Hachmeyer:“Every rubber mixture consists of natural or synthetic rubber, carbon or silica, waxes, oils and additives. The vulcanisation process - heating to 170 degrees at approximately 16 bar pressure – makes viscose rubber elastic. Exactly how flexible it is, will be determined by the additives. Each rubber mixture has characteristics on one hand viscous and on the other flexible, pliable and elastic. Gooey, viscous mixtures have more grip and can almost ‘stick’ to the road, while extremely elastic mixtures have very low rolling resistance. The respective relationship between the two characteristics can therefore be co-ordinated and controlled for its particular target application. Each rubber mixture is therefore a compromise between grip and rolling resistance.”

Question: Why does a tire need a triple compound?
Markus Hachmeyer:“In order to optimise different and opposing characteristics at the same time in a single tire, several compounds are necessary. The three prime attributes for Nobby Nic were - rolling resistance, grip and durability. But that meant we needed three rubber mixtures and they each had to be in a specific place, in total four different tread areas - centre, both shoulders and a base layer. This could only be achieved by using the ultramodern manufacturing process made possible by a Triplex extruder.”

Question: Why can’t a Dual Compound also optimise different characteristics?
Markus Hachmeyer: “With Dual Compound only two characteristics can be optimised. This double compound can consist of two rubber mixtures lying on top of each other; a combination we used for the first time in 2003 on Racing Ralph MTB tires. However, we have been using a Dual Compound with the two rubber mixtures lying next to each other in our Stelvio professional racing cycle tire since 1999.”

Question: How is Nobby Nic’s triple compound tread made up?
Markus Hachmeyer: “The flexible Qualifier Compound is used as a sub-layer, or base compound as it has very low rolling resistance, but - and here is the compromise - little grip. However, this disadvantage has no effect, because this compound does not come into direct contact with the road. Over it, in the centre of the tread, lies a layer of durable Off-road Racing Compound, because this is where the tread needs to be strongest. In addition this rubber mixture provides extraordinary traction under propulsion as well as good braking grip. Maximum Grip Compound is used on the outside tire shoulders which come into play when the bike is inclined during cornering - particularly important in wet conditions - ensuring very good grip. This compound is used for example in the Stelvio Rain and offers unsurpassed wet grip. With its rather gooey characteristics it adapts very well to unevenness.”

Further Information

Nobby Nic