To the average street bike and recreational motorcycle rider, the mysteries of MotoGP bikes and the way their riders ride them is a fascinating topic for discussion because of their speed and glamour. But you may wonder if some things are the same as for street bikes, like how they change gears.
MotoGP riders change gears by pushing a foot lever, the same as regular street bikes. But there are a number of differences in the gearbox construction, and the order of gears that MotoGP bikes utilize to enable the rider to change gears smoothly. This is to get maximum performance.
MotoGP bikes use a seamless gearbox that makes a big difference as it is designed to facilitate fast and easy gear changes. Keep reading as we take a good look at what goes on inside the MotoGP seamless gearbox and how it differs from a street motorcycle gearbox.
How A MotoGP Gearbox Works
Every MotoGP bike today uses a seamless gearbox that permits the rider to change gears without even a momentary drop in efficiency. During a race, any inefficiency by the rider or motorcycle translates into a loss of speed which can make all the difference between winning or losing a race. The gearbox is the second most important part of the bike, the first being the engine.
The seamless gearbox works differently in that it can engage two gears at the same time although this only actually happens for a very short time. The reason for this is to keep the engine driving the rear wheel all the time, except for the few hundred milliseconds when the gear change takes place. This minimizes the drop in speed and power that usually accompany gear changes.
Because it is responsible for transmitting the engine power to the wheels, it has to be extremely efficient in the delivery of power and torque. In an environment where time is calculated in thousandths of a second, a small power loss of only a few watts over time can make a difference.
The Secretiveness Of Engine And Gearbox Design
Due to the highly competitive nature of MotoGP racing as well as the vast amounts of money and reputation at stake for the winning manufacturer, the little information that is available about the gearbox is from patents that are filed by the manufacturer as well as press releases.
It is highly doubtful that most of the knowledge pertaining to MotoGP gearboxes will ever be made public, as each manufacturer prefers to reveal as little as possible about the inner workings of their machines. This knowledge can be used by rivals to improve their own bikes, hence is kept secret.
Whatever little information is available in the public domain on engine and gearbox design, as well as modifications, comes from press releases that are minimal, especially with reference to vital design aspects and it would not be right to expect full disclosure. Most MotoGP teams have only one person capable of repairing the engine who is completely familiar with their design secrets.
MotoGP Transmission vs Street Bike Transmission
There are several differences between a MotoGP transmission and a street bike transmission, but they are designed to do very different things and work under very different conditions. With this in mind we have to look at what they’re designed to do to understand the differences between them.
MotoGP Transmission: What It Is Designed For
The MotoGP gearbox is a highly sophisticated piece of machinery that is extremely expensive using the very best materials and design engineering. It is designed with only one purpose in mind: to be as efficient as possible. It takes the raw output power of the engine and converts it so that the rider can control it at will.
It is designed to operate under extreme heat while delivering maximum power, therefore it needs a specialized cooling system. A small pump is used with pipes that carry the liquid coolant into contact with the heat generating areas, then circulate it so that it carries away the heat. Different systems have been devised that use water, oil, or a separate coolant.
The gearbox itself is a marvel of engineering in that it can engage two gears at the same time even though this is for a moment. This is to ensure that power from the engine is delivered to the rear wheel continuously and smoothen the gap in power from gear changes. Any drop in momentum on a gear shift can cost a few hundred milliseconds.
Inside A MotoGP Gearbox
Every part inside a MotoGP gearbox is made from lightweight titanium where possible or from the strongest metal available. Because cost is not a factor here, many of its parts are custom made to ensure that they fit together perfectly but come with the disadvantage that certain parts are not readily interchangeable with another gearbox of the same type.
The gearbox is the crucial element in deciding the bike’s acceleration therefore each part inside it is manufactured to very high tolerances which costs a lot of money. Any part that goes out of tolerance by a few thousandths of an inch is deemed to have failed and is replaced. Most of the parts inside it will be replaced after one or two races as peak performance is needed all the time.
Each gearbox is optimized for power output that can be measured in test conditions before being used in a race. Gearboxes are being improved all the time which requires an existing gearbox to be modified to incorporate the changes. Riders are keenly aware of how roughly or smoothly the gears shift, so their feedback is taken into consideration to constantly adjust it.
Street Bike Transmission: What It Is Designed For
In a normal street bike gearbox, only one gear can be engaged at a time. Obviously, the street bike gearbox is less sophisticated and less expensive, and not designed to be as efficient as a MotoGP gearbox because it has different requirements. A street bike gearbox is designed to work in flat as well as hilly terrain carrying loads that can vary from the rider’s weight to very heavy.
It has to work in all sorts of weather conditions, from wet to sandy, muddy, and even in snow. In this wide range of temperatures and loads the gearbox needs to be able to supply enough power and torque when called on. All of this while being reasonably priced so as not to add too much to the overall cost of the motorcycle and requiring the bare minimum of maintenance.
Given that such a large number of considerations need to be taken into account, a street bike transmission does an excellent job and any comparison with a MotoGP gearbox is absolutely meaningless as both of them are designed for completely different objectives.
Inside A Street Bike Gearbox
Gearboxes for street bikes are standardized to conform to the requirements of low cost and functionality over a wide range of operating conditions. Most of the constraints that are imposed on MotoGP gearboxes are not applicable here which results in a completely different end product. They’re intended for rough-and-tough use for a number of years.
The outer casing is made from cheaper aluminum alloy casting while the parts inside are made from steel alloys that do not require very high strength. These gearboxes are designed to be rugged and work normally despite being used in far from optimal conditions. The average street bike gearbox is abused, poorly maintained, but expected to work for many years.
Every part inside it is freely interchangeable with a part from another gearbox of the same type. This means that it does not need parts that are manufactured to very high tolerances and can work even when some of the parts inside it display signs of extreme wear. Several parts work under strenuous conditions without needing to be replaced for years.
Do MotoGP Bikes Have A Clutch?
MotoGP bikes do have a clutch, but it is mostly used at the start of a MotoGP race when the rider has to start from neutral. During the race, most of them do not use the clutch as they prefer clutchless shifting or the quickshifter. It’s up to rider preference if they use the clutch during the race.
From the time of 4-stroke engines, MotoGP bikes have always used what is known as a slipper clutch because it helps in reducing lap times. A slipper clutch is a torque limiter that keeps the clutch from fully meshing until the engine speed matches the bike speed. It also ensures that there are no sudden jerks or abrupt vibrations that can upset the working of the transmission.
It is most useful while cornering because the rider can pay attention to cornering posture as well as getting the speed right. Slipper clutches are only found on MotoGP bikes and not on street bikes as they are quite expensive and to some extent unnecessary. Since their installation is relatively complex, it is simpler and cheaper to equip a street bike with a standard clutch.
The Quickshifter And Autoblipper
The quickshifter is a mechanism that allows the rider to change gears without using the clutch. It is partly electronic as it uses a microcontroller with a central processor unit to sense pressure on the gear and cut off the ignition when the new gear is engaged. This prevents excess load on the transmission while assisting a perfect gear change in less than a hundred milliseconds.
Some quickshifters do not work in both directions, but the ones that do are also called autoblippers. Quickshifters are readily available for street bikes and sold at any motorcycle store, although the price can vary a lot depending on the manufacturer and the type of sensing used to trigger the controller. A quickshifter can damage the gearbox if the ignition is not cut off during the shift.
The end result is to sense the gear shift and cut off the spark plugs momentarily as the new gear is moved into position, then restore normal ignition back to the bike. When the ignition is off, the engine speed decreases, and the rear wheel momentum drives the gearbox which makes the gear change smoother. A quickshifter is convenient to use as it removes the need to use the clutch and throttle.
Do MotoGP Bikes Have Neutral?
MotoGP bikes do have a neutral. In most motorcycles, neutral is between first and second gear, but in a MotoGP gearbox, neutral is below the first gear. It is activated by a lever which allows the foot pedal to go to neutral. This is to avoid accidentally putting the bike in neutral during a race.
Neutral is only used before a race and at the end, so it is used very rarely or under exceptional circumstances during a race. It is still essential as the engine cannot be started with a gear selected.
How Do MotoGP Riders Change Gears?
MotoGP riders change gears by pushing a foot lever. The foot lever connects to a complex slipper clutch mechanism that allows the rider to change gears with a minimal disconnect between engine and gearbox during the shift. This results in an even transition with less jerk and vibration.
The gears on a MotoGP gearbox are in reverse order compared to a regular street bike, so the rider has to push down on the foot lever to change gears up. Of the six gears in the gearbox, the highest gear is at the bottom with the lower gears above, and gear one at the top. This has become standard practice on every MotoGP gearbox.
When slowing down and changing gears the slipper clutch is especially useful because it prevents the engine from over-revving by partially slipping until the engine speed matches the bike’s speed. Slipper clutches have made their way to street bikes as many manufacturers offer to install them in their regular motorcycles at a nominal extra cost.
MotoGP riders use a foot pedal to change gears with a sophisticated slipper clutch mechanism. Champions that have raced for many years still use the clutch while others use a quickshifter, but for all of them, it comes down to their personal preference based on experience and riding style.
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