Sabtu, 15 Desember 2007
Grand Prix motorcycle racing refers to the premier category of motorcycle grand prix currently divided into three distinct classes: 125 cc, 250 cc and MotoGP. Grand prix motorcycles are purpose-built racing machines that are neither available for general purchase nor can be legitimately ridden on public roads; this contrasts with the various production categories of racing, such as the Superbike World Championship, that feature modified versions of road-going motorcycles available to the public.
There have traditionally been several races at each event for various classes of motorcycles, based on engine size, and one class for sidecars. Classes for 50 cc, 80 cc, 125 cc, 250 cc, 350 cc, and 500 cc solo machines have existed over time, and 350 cc and 500 cc sidecars. Up through the 1950s and most of the 1960s, four-stroke engines dominated all classes. In the 1960s, two-stroke engines began to take root in the smaller classes. By the 1970s, two-strokes completely eclipsed the four-strokes. In 1979, Honda made an attempt to return the four-stroke to the top class with the NR500, but this project failed, and in 1983, even Honda was winning with a two-stroke 500. The 50 cc class was replaced by an 80 cc class, then the class was dropped entirely in the 1990s, after being dominated primarily by Spanish and Italian makes. The 350 cc class vanished in the 1980s. Sidecars were dropped from World Championship events in the 1990s (see superside), reducing the field to 125s, 250s, and 500s.
MotoGP, the premier class of GP motorcycle racing, has changed dramatically in recent years.
From the mid-1970s until 2002 the top class of GP racing allowed 500 cc with a maximum of 4 cylinders, regardless of whether the engine was a two-stroke or four-stroke. Consequently, all machines were two-strokes, due to the greater power output for a given engine capacity. Some two- and three-cylinder two-stroke 500s were seen, but though they had a minimum-weight advantage under the rules, typically attained higher corner speed and could qualify well, they lacked the power of the four-cylinder machines. In 2002, rule changes were introduced to facilitate the phasing out of the two strokes, probably influenced by what was then seen as a lack of relevance: the last mass-produced 500 cc 2-stroke model had not been available to the public for some 15 years. The rules permitted manufacturers to choose between running two-strokes engines (500 cc or less) or four-strokes (990 cc or less). Manufacturers were also permitted to employ their choice of engine configuration. Despite the significantly increased costs involved in running the new four-stroke machinery, given their extra 490 cc capacity advantage, the four-strokes were soon able to dominate their two-stroke rivals. As a result, by 2003 no two-stroke machines remained in the MotoGP field. The 125 cc and 250 cc classes still consist exclusively of two-stroke machines. In 2007, the MotoGP class had its maximum engine displacement capacity reduced to 800 cc.
The current racing calendar consists of 18 rounds in 16 different countries (Spain which hosts 3 rounds, Qatar, Turkey, China, France, Italy, Great Britain, Netherlands, Germany, Czech Republic, San Marino, Portugal, Japan, Australia and Malaysia). Exclusive to the MotoGP class, there is also a USA round at Mazda Raceway Laguna Seca in Monterey, California for the 800-cc class only. In 2008 a MotoGP event will be held at the Indianapolis Motor Speedway (all three classes will race), racing counterclockwise on the Formula One track with additional turns directly after the pit area bypassing the banking turn one of the oval track. Also because of the race being run counterclockwise on what is normally a clockwise track the run off areas will need to undergo significant modification. The grid is composed of 3 columns (4 for the 125 cc class) and contains approximately 20 riders. Grid positions are decided in descending order of qualifying speed, the fastest on the 'pole' or first position. Races last approximately 45 minutes, each race a sprint from start to finish without pitting for fuel or tyres.
Tyre selection is critical, usually done by the individual rider based on bike 'feel' during practice, qualifying and the pre-race warm-up laps on the morning of the race, as well as the predicted weather. The typical compromise is between grip and longevity--the softer and 'grippier' the tyre, the more quickly it wears out; the harder and less grippy, the more likely the tyre is to last the entire race. Special 'Q' or qualifying tyres of extreme softness and grip are typically used by riders during grid-qualifying sessions, but they last typically no longer than one or two laps, though they may deliver higher qualifying speed. For wet conditions, special tyres ('wets') with full treads are used, but they suffer extreme wear if the track dries out.
New tire regulations introduced in 2007 limited the number of tires any rider could use over the practice and qualifying period, and the race itself, to a maximum of 31 tires (14 fronts and 17 rears) per rider . This introduced a problem of tire choice vs. weather (among other factors) that challenges riders and teams to optimize their performance on race day. This factor was greeted with varying degrees of enthusiasm by participants. For 2008 a spec tyre rule was being considered, where one brand would serve as a control tyre for the whole grid. Bridgestone had dominated in 2007 and Michelin riders Valentino Rossi, Nicky Hayden, Dani Pedrosa, and Colin Edwards all acknowledged shortcomings in Michelin's race tires relative to Bridgestone in 2007. Instead of a spec tyre, the rules for 2008 have been amended to allow more tyres per race weekend, 18 fronts and 22 rears for a total of 40 tyres. The lower number of tyres per weekend was considered a handicap to Michelin riders. The only MotoGP team using Dunlops in 2007, Yamaha Tech 3, will not be using them in 2008.
In 2005, a flag-to-flag rule for MotoGP was introduced. Previously, if a race started dry and rain appeared, riders or officials could red-flag (stop) the race and begin again on wet tyres. Now, if it begins to rain a white flag is shown meaning riders can pit to swap the motorcycle on which they started the race for an identical one, as long as the tyres are different (that is, intermediates instead of wets, or slicks instead of wets). Besides different tyres, the wet weather bikes have steel brake rotors and different brake pads instead of the carbon discs and pads on the dry bikes. This is because the carbon brakes need to be very hot in order to function properly, and the water cools them too much. Hence the conventional steel brakes. The suspension is also 'softened' up somewhat for the wet weather.
When a rider crashes, track marshals wave a yellow flag, prohibiting passing in that area; one corner back, a stationary yellow flag is shown and passing in this area of the track is prohibited; if a fallen rider cannot be safely evacuated from the track, the race is red-flagged. Motorcycle crashes are usually one of two types: lowsides and the more dangerous highsides, though increased use of traction control has made highsides much less frequent.
According to one estimate, leasing a top-level motorcycle for a rider is about 3 to 3.5 million dollars.
- See also: List of Grand Prix motorcycle racers
The top riders travel the world to compete in the annual FIM World Championship series. The circuit is perhaps most closely followed in Italy and Spain, home of many of the more successful riders at the moment. However, over the last couple of years there has been an increase in the number of riders competing from the USA. This has resulted in the reintroduction in 2005 of the US Grand Prix (albeit just for the MotoGP class, not 125 cc & 250 cc), an event staged at Laguna Seca where American Nicky Hayden took his maiden MotoGP victory. Another American, Colin Edwards, gained second place in that race. In 2006, Hayden repeated his winning performance at Laguna Seca, despite serious difficulties with the track that--though repaved in June 2006, and incorporating improved safety features--exhibited serious problems with surface deterioration. Hayden went on to win the GP championship of 2006, with winner of the past 5 titles, Valentino Rossi, coming in second. The track was resurfaced for the 2007 event, leading to concerns about tire choice on an entirely new racing surface.
The premier class in past seasons has been dominated by Italian Valentino Rossi, winner of the 2001 to 2005 titles. In an effort to beat Valentino's amazing consecutive victories, other companies have signed younger riders on newly designed machines. Honda in particular have taken this approach, with their 2006 racing plans being specific about winning with 'next-generation' teams, signing Toni Elías, Marco Melandri, Dani Pedrosa, and Nicky Hayden, all of whom are under 25. Ducati successfully employed a similar strategy for the 2007 season when they signed 21 year old Casey Stoner of Australia. After a string of victories and podiums the highly consistent Stoner earned Ducati and Bridgestone their first World Championship title at the Motegi round of the 2007 calendar.
The 2006 championship was the first in 14 years to be decided at the final race, with Valentino Rossi starting the race with an 8 point lead. Hayden finished 3rd with Rossi finishing 13th after crashing on lap 5 to give Nicky Hayden his maiden MotoGP World Championship title.
 Challenges for the designer
Like Formula One cars, grand prix motorcycles are generally made of lightweight and expensive materials such as titanium and carbon-fiber-reinforced plastic. They regularly feature technology not available to the general public, and part of their fan appeal derives from this sophisticated technology and the high degree of technical skill & knowledge demonstrated by the designers and manufacturers.
Examples of this technology include sophisticated electronics such as telemetry, engine management systems and traction control, carbon disk brakes, and advanced engine technology such as those seen on Honda's V5 RC211V and Aprilia's RS3 Cube. The latter employs the Cosworth-designed pneumatic valve actuation system, used in Formula One cars. In 2007 the Suzuki and Yamaha also used pneumatic valve actuation and Honda reported using that technology for its 2008 RC212V bikes based on its F1 experience. The latest addition to the MotoGP grids, the Ilmor/SRT X3 machine, seen at the Estoril (Portugal) and Valencia (Spain) events in 2006, reportedly uses a similar valve-actuation design, not surprising considering Ilmor Engineering's background in Formula One. Unfortunately, the high cost of participation and lack of sponsorship caused the withdrawal of the Ilmor in early 2007.
While MotoGP motorcycles are only raced at world championship level, the lighter and significantly less powerful 125 cc and 250 cc bikes are available at relatively reasonable cost. A basic production 125 cc bike costs about the same as a small car. These bikes are raced in national championships around the world as well as in the world championship, though their two-stroke technology is irrelevant in context with production machines. These two smaller classes are considered excellent training for future MotoGP riders.
One of the main challenges that confronts a MotoGP motorcycle rider and designer is how to translate the machine's enormous power - over 240 horsepower (179 kW), through a single tyre-contact patch roughly the size of a human hand. For comparison, Formula 1 cars produce up to 750 bhp (560 kW) from their 2.4 litre engines, but have 10 times the tyre-contact surface. Because of this difficulty, MotoGP is perhaps unique in modern motor sport in that teams will often deliberately detune their engines to allow their riders a chance to control them. In the two-stroke era, many of the 500 cc machines were not making more than the 180 to 190 bhp (135 to 140 kW) although their maximum potential power output was higher. In recent times this has begun to change with the advent of traction control. Part of the rider compromise, significantly affected by ECU (Engine Control Unit) technology, is that explosive torque at lower RPM may cause the rear tyre to spin unless modulated, causing riders to use higher RPM where torque changes are less severe. This consideration also affects gear selection for the individual circuit, which comprises an essential element in setup before and during practice and qualification.
Another significant issue in 2007 was the reduction in permissible fuel from 22 litres to 21 litres, causing engineers to introduce ECU control over maximum revolutions, where internal friction losses are highest, and leaning out the fuel-air mixture in sections of the track where maximum power is less necessary. Observers noted that the 800-cc machines were not using proportionately less fuel than the 990s because with their lower power output the smaller machines were using full throttle more of the time for a given circuit.
The following shows the key specifications issues for each class. It was also introduced for the 2005 year, that under rule 2.10.5: 'No fuel on the motorcycle may be more than fifteen °C (15 °C) below ambient temperature. The use of any device on the motorcycle to artificially decrease the temperature of the fuel below ambient temperature is forbidden. No motorcycle may include such a device.' This stops an artificial "boost" gained from increasing fuel density by cooling it.
 125 cc and 250 cc classes
125 cc machines are restricted to a single cylinder and a minimum weight of 80 kilograms and the 250 cc machines to two cylinders and a minimum of 100 kilograms. From 2005 onwards, all riders in the 125 cc class could not be older than 28 years or 25 years for new contracted riders participating for the first time and wild-cards.
 MotoGP class
New specifications for each racing class are formed as the FIM sees fit. At the beginning of the new MotoGP era in 2002, 500 cc two-stroke or 990 cc four-stroke bikes were specified to race. The enormous power advantage of the larger displacement four-stroke engine over the two-stroke eliminated all two-strokes from competition; the following season no two-stroke bikes were racing. In 2007 the maximum engine capacity was reduced to 800 cc without reducing the existing weight restrictions.
MotoGP-class motorcycles are not restricted to any specific engine configuration. Rather, the motorcycle's minimum weight is restricted depending on the number of cylinders. This is because an engine with more cylinders for a given capacity is capable of producing more power more easily. The greater the number of cylinders for a given capacity translates into less capacity per cylinder. As a result, the piston for the resulting smaller cylinder is also smaller, weighing less. Less reciprocating mass (such as pistons) require less energy to move and this aids to the engine being capable of achieving higher revolutions per minute and, hence, greater power. For this reason, the weight limit is increased as a form of handicap. In 2004 motorcycles were entered with three-, four-and five-cylinder configurations. A six-cylinder engine was proposed by Blata, but did not reach the MotoGP grids.
The FIM has become concerned, much as the FIA in Formula One, at the advances in design and engineering that result in higher speeds all around the race track since 2002. The current MotoGP speed record of 347.4 km/h (215.864 mph) was set by Loris Capirossi on a Ducati Desmosedici GP4 at IRTA Tests in Catalunya in 2004 with a 990 cc bike, while the speed record for a 800 cc bike is held by Casey Stoner on a Ducati Desmosedici GP7 at Grand Prix of China warm-up with top speed of 337.2 km/h (209.6 mph). By way of comparison, the current Formula One speed record of 369.9 km/h (229.8 mph) was set by Antônio Pizzonia of the BMW Williams F1 team, at Monza in 2004 -- however, top speed is only a small portion of the overall capabilities of any track machine and thus does not represent the difference between Formula One and MotoGP performance-wise in general. To ensure safety, they have agreed upon a set of regulation changes to reduce motorcycle speeds. These include changes in weight, fuel, and engine capacity.
|# of Cylinders||2004 Min||2007 Min||Difference|
|2 Cylinder||135 kg||137 kg||2 kg|
|3 Cylinder||135 kg||140.5 kg||5.5 kg|
|4 Cylinder||145 kg||148 kg||3 kg|
|5 Cylinder||145 kg||155.5 kg||10.5 kg|
|6 Cylinder||155 kg||163 kg||8 kg|
- In 2005, fuel tank capacity was reduced by 2 litres to 24 litres
- In 2006, fuel tank capacity was reduced by a further 2 litres to 22 litres
- From 2007 onwards and for a minimum period of five years, FIM has regulated in MotoGP class that two-stroke bikes will no longer be allowed, and engines will be limited to 800 cc four-strokes. The maximum fuel capacity will be 21 litres.
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