Metzeler has introduced two new slick tires – the Racetec RR Slick and Racetec RR Compk Slick – tailored towards racers and trackday enthusiasts. Both tires are deemed “NHS” (Not for Highway Service) meaning neither is DOT legal and purely meant for racetrack use. Both tires were developed using information gained from Metzeler’s participation in international road races and national superbike championships.
The Racetec RR Slick was developed with superbike racing in mind, where DOT rated tires are not mandatory. Development was performed primarily on circuits with riders like Guy Martin, Ian Hutchinson and Gary Johnson with the objectives being:
Significant research and development went into the Racetec RR, of which you can read below in the full press release. Meanwhile, the Racetec RR Compk Slick, which is meant for non-competitive use, is constructed from a different compound than the Racetec RR to give the trackday rider a tire much more adaptable to changing temperatures and asphalt conditions, while providing longer tire life.
See the full Metzeler press release below for more information.
The METZELER brand is pleased to announce that this year professional riders and track enthusiasts all over the world will be able to rely on two new dedicated slick products, RACETEC RR SLICK, for racing, and RACETEC RR COMPK SLICK, for track day events these are different than the DOT approved RACETEC RR tires introduced in 2015, since both of these new products are slick and are NHS (“Not for Highway Service”), but intended only for use on the track or in Road Racing competitions where allowed by the regulations.
The key characteristics of the RACETEC RR SLICK, dedicated to use in the Superbike categories in the various national championships and in Road Racing events, are grip, handling and riding precision when pushing to the limit in situations typical of high level competitive events, versatile use in terms of high adaptability to different types of asphalt, temperatures and motorcycle, simplicity of use, long life and consistent performance. For non-professional competitions, amateur use or simply for track days the METZELER brand has designed the new RACETEC RR COMPK SLICK.
Who are the intended users of the RACETEC RR SLICK and RACETEC RR COMPK SLICK
RACETEC RR SLICK is dedicated to all those riders involved in competitive track events or road racing where the Superbike category rules allow the use of an NHS tyre and where top shelf performance is demanded which only a slick compound product can provide. Precisely because of the characteristics in terms of performance and versatility, consistency and duration, RACETEC RR SLICK can be used by professional or semi- professional riders both for racing and training.
RACETEC RR COMPK SLICK, on the other hand, was designed specifically for those users who, although not professional riders, love riding on track days or are simply amateur or beginner riders who want to train by racking up the miles to find the best setup for their bikes without necessarily looking for absolute top of the line performance.
The range and the pedigree: RR like Road Racing
The METZELER range of products dedicated to racing was recently expanded with a large number of products that cover various applications and motorcycles, a sign of the brand’s efforts in this segment.
RACETEC RR SLICK and RACETEC RR COMPK SLICK represent the latest slick advancements in the RACETEC family, the line of METZELER products dedicated to racing and as much for professional use as for amateur.
The abbreviation RR indicates the context in which this project was conceived, the Road Racing world. In fact, beginning in 2013, the METZELER brand began investing heavily in road racing competitions, using them as a development platform and revamping its supersport and racing range. Putting to good use all of the experience and know-how acquired thanks to participation in the most prestigious road races such as the Tourist Trophy Isle of Man, the North West 200, the Southern 100, the Metzeler Ulster Grand Prix and the Macau Motorcycle Grand Prix, in just over two years the brand with the baby elephant developed and placed on the market an impressive four new products labelled with a double “R” in the name.
The RR family was born in 2014 with the SPORTECTM M7 RR, a sport tire for road use, expanded in 2015 with the RACETEC RR, a DOT approved supersport racing tire intended for use on the track and for maximum road performance, and it is completed this year with the introduction of the new RACETEC RR SLICK and RACETEC RR COMPK SLICK.
These last two products were developed and tested both on the track and in road races in order to provide equal benefits for riders in both specialities.
The professional racing range is now complete: alongside the new RACETEC RR SLICK, dedicated to use in the Superbike categories in the various national championships and in Road Racing events, METZELER offers RACETEC RR (in the K1 and K2 versions) for races which require DOT approved tires and RACETEC SM for the Supermoto discipline.
For the amateur racing or track day rider, on the other hand, riders can choose between the RACETEC RR COMPK SLICK and the DOT approved RACETEC RR in K3 compound.
All of these tires are for use on dry roads. In the event of rain, the RACETEC Rain tire is available.
Characteristics and advantages of the RACETEC RR SLICK
The RACETEC RR SLICK was developed with the goal of providing the best possible performance both for use on the track and in road racing. For this reason, development was carried out primarily on circuits, with calibration and testing done both on the track and during road races with riders of the calibre of Guy Martin, Ian Hutchinson and Gary Johnson.
Road Racing is one of the most difficult and demanding sporting events because of the combination of factors such as long race distance, high average speeds, altitude and temperature variations and the varying road surface quality. RACETEC RR SLICK was designed to tackle all of these different situations that may be found in a single race, providing unrivalled high mileage and consistent performance along with extremely good versatility.
Developed on the track and also tested in Road Racing to provide the best possible performance in both worlds, RACETEC RR SLICK boasts the following characteristics:
Grip and agility
The work carried out to improve the key performance factors is described in detail below:
The rear RACETEC RR SLICK tyres underwent an important update in terms of size with respect to the RACETEC SLICK predecessors, going respectively from 180/55 to 180/60 and from 190/55 to 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, thanks to the widened contact surface that is created by the larger diameter, as well as by the larger cross section in the case of the rear 200 tire.
The front RACETEC RR SLICK tyres were 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, which means that there is more rubber on the ground to increase grip.
For the front and rear sizes, the new profiles also required a new structure with particular focus 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. 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 carcass ply but made of rayon, a more flexible material than aramid, combined in this case as well with the 0° steel belt.
The most important aspect of predictability applied to racing tyres lies in their ability to alert the rider when they are coming to their limit in terms of grip. In the braking phase and when leaning over to enter a turn, the rider perceives this warning in the form of a progressive reduction in contact feeling on the handlebar which goes hand in hand with a widening of the trajectory due to the rear tire which slides slightly. Managing this extreme limit situation is what lets a good rider go faster: RACETEC RR SLICK, with a front tire that uses a dual ply aramid carcass combined with the 0° steel belt, has neutral performance that improves the perception of this alert, making it easier for the rider to take advantage of it.
Coming out of turns it has a similar dynamic which, however, involves the rear tire that alerts the rider when it is approaching its limit through a slow and progressive lateral sliding which causes the trajectory to close. RACETEC RR SLICK helps to make this extreme limit performance more linear and gradual both for the semi-professional and expert rider: the former is able to better monitor the situation in order to adjust speed or trajectory and recover optimum stability, whereas the latter can continue to push to the limit in order to come out of the turn as fast as possible. This advantage was obtained by using a sturdy carcass in rayon, which guarantees stable and neutral performance, reducing lateral deformation, in combination with the 0° steel belt that improves the feeling of the contact area and the adaptability to the micro-bumps in the asphalt.
An important role in improving the predictability of limit situations that was reached was also played by the work carried out in optimising the front and rear profiles: if the rear tires have completely new sizes, having gone from /55 to /60, the profile of the front tyres was also modified to work together with the rear sizes in providing neutral performance, the best suited to let riders have riding precision and easy operation when pushing to the limit.
3) Adaptability to different types of asphalt, temperatures, bikes and setups
In order to allow riders to easily take advantage of the performance offered, RACETEC RR SLICK was developed to obtain a high level of adaptability to a wide range of bikes, without needing to find the perfect setup. The structure of the rear tyre carcass, single ply (unlike many products in this segment which use a two-layer carcass) and combined with the 0° steel belt, is much more similar to structures adopted for street oriented products, therefore even making it possible to use the standard chassis settings that the bike and tyres were developed with, resulting in the relative advantage of an easy setup.
Development of the compounds was carried out always keeping versatility in mind: the RACETEC RR SLICK compounds are designed to provide a wider spectrum of use in terms of asphalt and temperature severity. This translates into not only more freedom for the rider in choosing a compound, but it also means that the tyre will have higher performance with respect to the competition, even when optimum track conditions progressively decrease.
This result was achieved using low glassy transition polymers, which means that the molecules that make them up maintain their mobility even at low compound temperatures, resulting in a softer blend and optimum grip even during the warm-up phase.
The adaptability on asphalt with different friction coefficients was achieved using specific resins that maintain their mechanical resistance (in other words, the ability to maintain their physical properties) even at a higher compound temperature (tire overheating). The result of adding these resins to the blend recipe was that we were able to improve the correspondence between the contact area and the asphalt, both on surfaces with a low friction coefficient (slower compound heating rate) and with higher ones (faster compound heating rate).
4) Consistency in performance
The efforts in developing the compounds also went in the direction of consistent performance over distance (kilometres or laps) and time (thermal cycles). Focusing on thermal cycles, the addition of specific resins in the compound compositions and the use of a specific mixing process allow RACETEC RR SLICK to be used even after the first thermal cycle has ended.
Even wear and resistance to wear was achieved thanks to a patented blending process for the compound elements that guarantees optimum dispersion of them in the rubber structure.
The new profiles and the shape of the contact area also help in the redistribution of the stress created on the tyre’s surface layer over a larger area and the structural parameters of the carcass transfer them toward the sidewall, where they are dissipated by the tread.
RACETEC RR SLICK is available in the K1 and K2 compounds. Rider will easily be able to distinguish one compound from the other thanks to the label applied to the side and the coloured stripe on the tread band.
For the front slick solutions, the criterion for which to use is based not only on outdoor temperature and type of route (many bends or long straights, hollows, etc.) but also on the rider’s aggressiveness/riding style that affects the front tyre.
The choice of which front tyre to use should be made based on whether the rider prefers greater stability and precision going into turns (K2 version) or predictability and the feeling of perceiving the “grip limit” (K1 version).
As regards weather conditions, when the track temperature increases, the compound tends to lose its compactness and rigidity. This behaviour can cause movement in the leaning stage. A stiffer compound like the K2 minimises this effect. On the other hand, when the track is cold, the compound tends to become more rigid, to the detriment of grip and stability while braking. In these conditions it is better to use a soft compound such as K1.
As regards the rear solutions, the criterion for which to use is based on the severity of the asphalt, on the temperature and on the duration of the performance required (long-run). For example, hot asphalt loses some of its natural mechanical grip becoming smoother and more slippery. In these conditions a soft compound (such as K1) is necessary, as it can stick to the asphalt surface as much as possible.
A cold asphalt, on the other hands, tends to be more aggressive and rougher, offering more mechanical grip which can nevertheless cause the tyre to rip and tear tyre which therefore needs a compound with more resistance (such as K2).
The compound of the RACETEC RR COMPK SLICK is unique because it is dedicated to non-competitive use and can be used at any temperature, in any asphalt grain condition and it is capable lasting significantly longer.
RACETEC RR SLICK will be available soon for purchase at your local METZELER dealer in the following sizes and compounds:
120/70 R 17 K1, 120/70 R 17 K2
180/60 R 17 K1, 180/60 R 17 K2, 200/60 R 17 K1, 200/60 R 17 K2
RACETEC RR COMPK SLICK will be available for purchase soon in the following sizes:
120/70 R 17
180/60 R 17, 200/55 R 17