In an effort to gain an advantage in MotoGP, many of the teams have experimented with various ways to improve the bikes’ speed and handling. One way they can do this is by tweaking the suspension, leaving many fans wondering if MotoGP bikes are lowered.
MotoGP bikes are lowered, but only at the start of the race using a device referred to as a holeshot. This allows for faster acceleration off the starting line by lowering the rear of the bike by about 25-40+ mm. Compared to normal motorcycles though, MotoGP bikes aren’t really lowered.
Since 2018, MotoGP bikes have been using devices that allow the rider to decide when to alter the suspension height while the bike is moving. Join us as we take a deep look at the reasons behind their usage, and their benefits, in the article below.
MotoGP Suspension Setup Explained
MotoGP bikes are built according to the height and weight of the rider. Since there are no rules on uniformity of chassis, the individual advantages of the rider are taken into consideration. But MotoGP bikes can only be so low, as the riders take some extreme lean angles (often greater than 40 degrees), and this means footpegs can come into play.
If the bike is extremely low to the ground, and the rider tries to take an extreme lean angle through a corner at high speed, the footpegs and their boots could easily touch the ground. This could be catastrophic at high speeds, so there is a limit as to how low a MotoGP bike can go. This means the suspension system has to be set up to account for this.
The suspension system consists of various components, including springs. Springs are the main part that supports the weight of the bike along with oil damping that is sometimes used. Springs are manufactured with different degrees of stiffness measured in Newtons per millimeter and are changed depending on how much spring stiffness is needed for each track.
The softer spring provides less stability during braking when the spring can reach maximum compression, while the stiffer spring gives more support but with higher tire wear. The spring can be changed in a few minutes by opening the front fork cap, removing the existing spring, and then inserting a different spring with the requisite amount of stiffness according to what the rider needs.
The preload is the amount of spring compression in the fork when the bike is not moving, and the amount of preload determines how much force is needed to compress the spring completely. The complex suspension system on the bike provides balance and traction, and this is very important at the race start, which is where ride height devices come in to adjust the suspension.
How Do MotoGP Ride Height Devices Work?
MotoGP ride height devices work by lowering the center of gravity of the bike. The height of a MotoGP bike is determined by its wheel radius plus the height of the suspension. Since the wheel radius is fixed, the only room left to adjust the height is by reducing the suspension length. Ideally, the rider would want the suspension to be at its lowest when the bike is accelerating at the highest rate.
Devices that allow MotoGP riders to adjust their ride height by altering the suspension at the start of a race are called holeshot devices. These devices don’t modify the compression of the spring (as that takes a lot of energy) and instead they modify the length of a link that connects the chassis to the swingarm at the back of the bike, which functions a bit like a shock.
We can think of the swingarm here as being like a seesaw, or teeter-totter. When one end is pushed up, the other end naturally goes down. We can think of the end with the rear wheel attached as the end of the teeter totter being pushed up, causing the end attached to the bike’s chassis (at the other end of the linkage) as being pushed down.
While it may sound counterintuitive, when we push the end attached to the wheel higher up, the chassis naturally drops down, lowering the ride height at the back of the bike. This is because we’re not pushing the wheel itself higher up off the ground (we couldn’t, as the weight of the bike is too great for this linkage to actually lift the wheel).
Instead what happens is the other end of the teeter-totter, the end connected to the chassis, is simply ‘pulled’ down. This means the chassis lowers, which lowers the center of gravity of the bike, allowing for faster acceleration (we’ll go into more detail about the specifics of how this works below).
When Is A Holeshot Device Used?
You may have noticed MotoGP bikes doing wheelies many times at the start of the race. The torque generated at the rear wheel as a result of the massive power output of the 1000cc engine makes the bike almost function like a lever and fulcrum, with the front of the bike naturally wanting to lift up off the ground.
Essentially, the rotational force at the rear tire combined with a high level of grip to the track surface makes the entire bike begin to rotate around the rear tire. The rotation isn’t much, but it’s enough to lift the front of the bike off the ground. The weight of the rider and the bike itself, along with throttle management, are enough to prevent the bike from fully tipping over backwards.
When a MotoGP bike does a wheelie, it’s a result of energy that is going into the back tire being wasted lifting the front wheel when it should be used to propel the bike forwards. So, clearly a rider would rather the bike didn’t do a wheelie so they can use more of their power to go forwards, increasing their rate of acceleration.
Ride Height Devices
In MotoGP, there are also ride height devices that can be used multiple times during a lap, allowing the rider to have a lower center of gravity, and therefore a more stable bike, at their command. However, the main benefit is that they can use this out of slow corners that have a long straight after them, allowing them to accelerate faster and therefore reach higher top speeds.
KEY FACT: Any devices that allow a MotoGP rider to lower the suspension outside of the race start (i.e. one-time use holeshot devices) are banned from 2023
Why Center Of Gravity Is Important In MotoGP
The center of gravity (CoG) of a body can be defined as the point where the weight of the body is concentrated. In any sport the center of gravity plays an important role as it helps in increasing stability and balance. The center of gravity of a motorcycle is an imaginary point, but it has a big say in many design parameters that are optimized according to it.
As the height of a body increases, so does its center of gravity, making it easier for it to topple over. The shorter the body, the more stable it is. On a bike, the center of gravity cannot go below an imaginary line drawn through both the front wheel and rear wheel axles. In reality, the height of the front and rear suspension has to be added to the axles’ height.
A Low Center Of Gravity Prevents Wheelies
MotoGP engines generate an abundance of power, which is available to the rider by opening the throttle. It is easy to open it too much, thereby causing an unwanted wheelie by sending too much power to the rear wheel. But if the rider has lowered their suspension prior to opening the throttle, the center of gravity of the bike is lowered too.
This means the bike can be thought of as being more stable (when compared with having a higher center of gravity), and therefore in order to lift the front wheel, more energy is required at the rear wheel. This in turn means that the rider can open the throttle more than they normally could without lifting the front wheel.
But when the bike begins to wheelie, the anti-wheelie system reduces the power from the engine to bring the front wheel back down. This obviously reduces the power at the rear wheel, reducing the rider’s rate of acceleration. If you can prevent this system from kicking in by limiting wheelies in the first place with a lower CoG, you can accelerate faster.
Why Would MotoGP Ride Height Devices Be Banned?
While the holeshot devices used at the start of the race remain legal from 2023, any device that allows for the lowering of the front suspension while racing is banned. This is because the FIM are concerned about the higher top speeds these devices can allow during a race.
The holeshot devices are only used at the race start. This means that, while it does give the riders faster acceleration, they’re only benefitting in this way from a standing start and until the first corner. While they will reach a higher top speed faster than they would without the device, the top speed into Turn 1 will still be lower than if a rider was on a flying lap into the same corner.
So, the top speed at the race start isn’t of a concern, but the top speeds during the race are worrying enough to cause the commission to ban the multi-use suspension altering devices from 2023.
KEY POINTS• While MotoGP bikes aren’t always lower than most production bikes, they do feature adjustable suspension components
• These adjust the ride height of the bike to improve acceleration
• They do this by lowering the center of gravity of the bike
• The holeshot devices used at the start of races remain, but from 2023 any front ride height devices are banned
MotoGP bikes aren’t lowered compared to normal motorcycles, but the bikes’ ride heights can be lowered using ride height devices. From 2023, the only legal form of this is called a holeshot device. It’s used at the start of the race to lower the rear ride height, allowing for faster acceleration.