The MICHELIN PRO4: the bicycle tyre which pushes out the envelope on all fronts
The challenge in the case of the MICHELIN PRO4 was to produce a range of tyres that were capable of going more quickly. But that wasn’t all. For three years, Michelin’s engineers also worked to push out the performance envelope on several seemingly irreconcilable fronts at the same time.
The new family of Michelin PR04 road tyres for exacting cyclists comprises four products:
• MICHELIN PRO4 Endurance
• MICHELIN PRO4 Service Course
• MICHELIN PRO4 Comp Service Course
• MICHELIN PRO4 Comp Limited Service Course
The quest for maximum efficiency for these different forms of cycling served as the cornerstone for each one of these four innovative tyres. As the only point of contact between the bike and the ground, tyres need to cover all the different conditions that cyclists are likely to encounter, from dry to damp and wet road surfaces. For example, the MICHELIN PRO4 Service Course improves cornering speed* in the wet by 16 percent. In addition to delivering enhanced speed and safety, it also provides outstanding protection against cuts and features new dual-compound technology. As a consequence, the MICHELIN PRO4 Service Course considerably extends tyre life** and stands out as a new benchmark.
Meanwhile, the rolling efficiency of the MICHELIN PRO4 Comp Service Course has been increased by an average seven percent*** over its predecessor to deliver unprecedented performance. It is this balanced performance package which characterises Michelin’s approach when it comes to research and development. Indeed, the fact that an improvement on one front is never achieved to the detriment of another is a hallmark of Michelin’s innovations.
* 25.6kph at a lean angle of 27.5 degrees for PRO4 compared with 22kph and an angle of 21 degrees in the case of PRO3 Race (test carried out round Michelin’s 56-metre circumference circular test track using a special Michelin test bicycle).
** Results based on input from 25 different riders. In total, the tyres which underwent testing covered more than 250,000km.
*** At a speed of 15kph, the MICHELIN PRO4 Comp Service Course uses seven percent less energy (22.4 watts compared with 24.7 watts) compared with the PRO4 Service Course
Technology:
MICHELIN PRO4: a range of four tyres for exacting cyclists
The MICHELIN PRO4 range comprises four different tyres and has been tailored to cover the different needs of exacting cyclists, from the quest for high performance in all types of conditions, to an exclusive, fast and extremely lightweight tyre for against-the-clock competition.
MICHELIN PRO4 Endurance: longer tyre life and enhanced protection
This tyre was designed to meet the needs of riders who place the emphasis on endurance. Thanks to its reinforced protection against punctures and cuts, the MICHELIN PRO4 Endurance combines high performance with outstanding durability. The performance of the MICHELIN PRO4 Endurance stems from the combination of several innovations:
• Its dual-compound tread is designed to ensure exceptional resistance to wear and enhanced grip when leaning through corners. The grey, yellow and blue compound employed for the shoulders provides a very high level of grip on wet roads, while the compound used for the central part of the tread delivers greater protection against punctures and impact damage.
• The combination of the 110TPI casing and bead-to-bead breaker ply ensures outstanding resistance to perforation and contributes to the tyre’s remarkable durability.
MICHELIN PRO4 Service Course: performance in all circumstances
The MICHELIN PRO4 Service Course delivers the best trade-off between sports performance and long tyre life. The achievement of the engineers is to have simultaneously enhanced its speed, safety, agility and resistance. The MICHELIN PRO4 Service Course is not only safer but it is also an average 16 percent faster when cornering on wet road surfaces*.
These improvements were achieved thanks to its optimised dual-compound technology which features:
• Wider lateral bands for optimal grip at all angles of lean
• New compounds incorporating new elastomers and silica for extra grip at the shoulders.
The tyre’s new, more pointed profile optimises the contact patch when leaning into corners for extra grip, as well as enhanced agility. At the same time, the specific compounds employed by the latest dual-compound technology provide superior rigidity for the central part of the MICHELIN PRO4 Service Course’s tread band – the part of the tyre which is exposed to the biggest constraints – for even longer tyre life.
Finally, the MICHELIN PRO4’s resistance to cuts, thanks to the presence of a nylon high-density breaker beneath the tread, considerably reduces the risk of perforation.
MICHELIN PRO4 COMP Service Course: the emphasis on rolling efficiency
This tyre targets exacting cyclists who place the emphasis on rolling efficiency. As a consequence, the new MICHELIN PRO4 COMP Service Course delivers unprecedented rolling efficiency which is an average seven percent superior* to that of the MICHELIN PRO4 Service Course. This remarkable result is due to the tyre’s new 150TPI casing (600 threads/dm). As a consequence, the casing is 30 percent lighter, while the tyre’s overall weight has been reduced by 10 percent compared with that of the Michelin PRO3 Race. The new tyre’s total weight is just 180g and its rolling resistance is consequently extremely low at 3kg/t. In addition to this unprecedented level of rolling efficiency, the MICHELIN PRO4 COMP Service Course delivers exceptional grip in the wet (cornering speed in the wet up 16 percent), while its agility and durability are also of a very high standard for this type of tyre.
These improvements are due to four different innovations:
• The MICHELIN PRO4 COMP Service Course’s new dual-compound technology incorporates new elastomers and new silica-based compounds
• The contact patch is optimised thanks to the tyre’s remarkably supple casing. The use of less dense threads enables this tyre to take irregularities in the road surface in its stride
• A high-density nylon breaker laid beneath the tread considerably enhances the MICHELIN PRO4 COMP Service Course’s resistance to cuts, New 150 TPI Fabric Nylon high density breaker
• The tyre’s new, more pointed profile optimises the contact patch for even more agile performance.
MICHELIN PRO 4 COMP Limited Service Course: for extra speed
This tyre is exclusively given over to the quest for extra speed. It is the range’s fastest tyre and allows cyclists to cover four additional metres per minute for the same input compared with the MICHELIN PRO4 Service Course. Acceleration of 250 watts over a period of 60 seconds enables the tyre to cover 544 metres and reach 38.4kph. It also delivers the market’s lowest rolling resistance (2.8kg/t), for a weight of just 165 grams.
Yet this performance does not detract from the remarkable grip and handling that are hallmarks of the tyres that make up the range.
Its dual-compound technology employs new silica-based compounds and elastomers. The compound used for the central part of the tread has been selected for long tyre life and low rolling resistance, while the compounds used for the shoulders favour grip as the rider leans through corners.
Finally, the contact patch of the MICHELIN PRO 4 COMP Limited Service Course is optimised thanks to the tyre’s supple casing. The use of finer threads enables it to soak up irregularities in the road surface.
* Tests carried out using a Michelin rolling resistance measuring rig.
The accent on innovation:
Research and innovation are two fundamental features of the MICHELIN PRO4 range
Research and development have always been essential driving forces at Michelin, and the MICHELIN PRO4 range has benefited extensively from this philosophy. Thanks to this new range of cycling road tyres, Michelin intends to maintain its number one status both in this domain as well as in the field of mobility solutions. In 2010, a budget of €545 million was allotted to the Michelin Group’s Technologies Centre.
Throughout the company’s history, the bid for innovation and research into new technologies that are of genuine benefit to customers have been at the heart of Michelin’s strategy. These innovations serve to meet the needs of the users of its products and also to shape mobility in the future thanks to safer tyres which make less of an impact on the environment.
The scope of these activities is extremely broad and extends from an understanding of fundamental chemical and physical phenomena to the creation and evaluation of prototype products, not to mention production feasibility. The availability of research facilities on three continents ensures a thorough understanding of local usages. It also facilitates collaboration work with top independent research laboratories and permits technical partnerships that bring complementary skills to the table.
The development of the MICHELIN PRO4 range called for no less than three years of research, plus hundreds of tests for each of the range’s tyres which involved covering some 250,000km. It was in France, at the Ladoux Technology Centre near Clermont-Ferrand (which was created in 1965 and which employs a staff of 3,400), that all the research, innovation and testing work took place. Subjective and objective testing, both on rigs and on the test track, played an essential role during the development of the new Michelin Pro4 range, with each performance factor evaluated separately. This testing programme ensured a detailed understanding of the tyres’ functional properties and allowed the engineers to evaluate their rolling resistance, their grip on both dry and wet roads, their resistance to cuts and their durability. To this end, Group’s bicycle tyre department used advanced and, in some cases, purpose-designed tools.
Lateral grip on wet road
Michelin developed this unique three-wheeled bike to test lateral grip in the wet, i.e. through corners. The third wheel, added for safety purposes, can be set at an angle of between 20 and 40 degrees. The aim of the test was to measure the maximum possible lean angle on wet roads. A patent has been registered for this apparatus.
Rolling resistance
It is this patented rig which Michelin uses to measure the rolling resistance of the different tyres produced by the Group (cars, trucks, bikes, etc.). The extremely precise results it delivers played a key role in the development of the MICHELIN PRO4 range. Tyres are placed on a drum while load and pressure are carefully controlled. The deceleration of the drum is measured as pressure is applied to the tyre. The rolling resistance coefficient indicates the energy lost because of the tyre: the lower the figure, the more efficient the tyre.
The tyre was submitted to other tests in the course of its development, including its resistance to cuts and tearing, its durability and ozone testing.
A little bit of history:
The same philosophy for 120 years
Ever since the very early days of bicycle tyres, Michelin has stood out as a pioneer. Today, in 2011, the philosophy that drives the Michelin Group hasn’t changed, as illustrated by the new MICHELIN PRO4 range.
Michelin’s history dates back more than 120 years to 1889 when brothers André and Edouard Michelin laid the foundations for what would become a formidable human and industrial adventure, with the focus on innovation to facilitate modern means of transport, promote freedom and stimulate economic growth.
The first bicycle tyre dates back to 1891. The Michelin brothers were visionaries who caught the majority of their contemporaries off-foot.
The strength of their idea lay in the fact that it enabled a punctured inner-tube to be replaced in just 15 minutes, using mechanical means without the need to call on a specialist. It was a removable tyre which anybody could repair.
The Michelin brothers applied for three patents for their removable, repairable tyre in the summer of 1891, including one that was registered less than a month before the start of the celebrated Paris-Brest-Paris road race which was an unprecedented 1,200km in length.
Even more worried than the bicycle manufacturers, André and Edouard Michelin inspect French racer Charles Terront’s bike to verify one last time the rims for which they have adapted their invention, the Michelin “removable” tyre. The two brothers are the only people who believe in the tyre, which is about to make it official debut.
Exactly 71 hours and 18 minutes after the start, Charles Terront crossed the finish line to win the inaugural Paris-Brest-Paris race by a margin of almost nine hours over his closest rival. “The winner tells us that he owes his success to his tyres,” it was reported in the papers the day after Terront’s victory.
In 1892, another event allowed Michelin to showcase the efficiency of its removable tyre: the “Course aux Clous”. On a course that ran from Paris to Clermont-Ferrand, Edouard Michelin had nails placed on the road to ensure the success of his riders who were competing on removable tyres that could be changed in three minutes. For the first time, competitors were able to benefit from a technical support service during the competition.
PR Manager Michelin Nordic: Lotta Wrangle
Phone: +46 8 709 07 76, Mobile: +46 72 250 07 40, E-mail: lotta.wrangle@se.michelin.com
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