Metzeler adds slick tyres to Racetec RR range
Two new dedicated slick products have entered the Metzeler motorcycle tyre portfolio in 2016. The new treadless pair are the Racetec RR Slick for racing and the Racetec RR Compk Slick for training and amateur track use. Unlike the treaded Racetec RR tyre introduced last year, both new products are NHS (Not for Highway Service) designated and intended only for use on tracks or where allowed by the regulations in road racing competition.
Metzeler Moto UK says the key characteristics of the Racetec RR Slick, which is intended for use in Superbike racing and road racing events, are grip, handling and riding precision even when pushed to the limit: “They are versatile in terms of high adaptability to different types of asphalt, temperatures and motorcycle, simplicity of use, long life and consistent performance.”
Who are the new tyres aimed at? The Racetec RR Slick is aimed at riders involved in competitive track events or road racing where the Superbike category rules allow the use of an NHS tyre and where a level of performance that only a slick compound product can provide is demanded. The tyre can be used by professional or semi-professional riders both for racing and training. The Racetec RR Compk Slick, on the other hand, was designed specifically for non-professionals who enjoy track day riding and want to put in the training miles to find the best setup for their bikes without necessarily looking for absolute ‘top of the line’ performance.
The ‘RR’ label stands for Road Racing, an area the Metzeler brand says it began investing heavily into in 2013. Metzeler utilised road racing competition as a development platform for revamping its supersport and racing ranges, and in just over two years the brand developed and brought four new ‘RR’ products to market – the first tyre to be rolled out was the Sportec M7 RR, a sport tyre for road use, and this was followed last year by the Racetec RR, a DOT grooved supersport racing tyre intended for use on the track and for maximum road performance. The racing range is now completed with the introduction of the two new additions.
Racetec RR Slick
When developing the rear Racetec RR Slick tyre, Metzeler opted to tweak the sizes; the 180/55 size used in the predecessor tyre is now a 180/60, while the previous-generation 190/55 size is now a 200/60. The choice to use 60 as the height ratio was motivated by the goal of providing maximum grip for the entire curvature radius through widening the contact surface area, as well as by the larger cross section in the case of the rear 200 tyre.
The front Racetec RR Slick tyre was redesigned from scratch: In order to ensure well-balanced performance in combination with the new rear sizes and to achieve better grip, the front sizes have a new profile with a larger external diameter. The new profile is now narrower, improving agility and creating a larger contact area, and thus more rubber on the ground.
The new profiles for both the front and rear fitments also required a new structure that focused on the balance between flexibility, which allows the contact surface to grip the asphalt copying its micro-bumps, and stiffness, which improves precision in braking and going into turns. Metzeler says the optimum balance was achieved on the front sizes using two plies of aramid combined with the 0° steel belt, whereas on the rear it was achieved using a sturdier casing ply made of rayon, a more flexible material than aramid, combined in this case with a 0° steel belt.
Predictability is important in racing tyres as it warns when a rider is reaching the limits of grip. When braking and when leaning to enter a turn, the rider perceives this warning in the form of a progressive reduction in contact feeling on the handlebar along with a widening of the trajectory due to a slight slide from the rear tyre. The front tyre’s dual ply aramid carcass combined and 0° steel belt has a neutral performance that improves the perception of this ‘feeling’ or warning. When coming out of the turn it is the rear tyre that alerts the rider of an impending grip limit through a slow and progressive lateral sliding which causes the trajectory to close. The Racetec RR Slick is designed to make this occur in a more linear and gradual way and does so through the use of a rayon casing combined with 0° steel belt.
The Racetec RR Slick is available in soft K1 and medium hard K2 compounds.
Racetec RR Compk Slick
The Racetec RR Compk Slick is an entry-level slick-tread product conceived for amateur rider training or for participating in track days. A key advantage the tyre offers, says Metzeler, is its “vast versatility” and “ease of use.” The Racetec RR Compk Slick does not require specific bike settings in place and it offers consistent performance when in use with different types of asphalts, temperatures and bikes.
While the 200/60 size was used for the Racetec RR Slick, the Racetec RR Compk Slick is produced in 200/55, a size more commonly seen in road use and therefore a size that riders can adapt to more quickly.