MotoGP

How does the MotoGP holeshot device work?

7 minutes

There are terms that have now become familiar in motorcycle language: boxes, pit lane, warm up, seamless… The latest one that we have incorporated is holeshot, but what exactly is a holeshot device?

How does the MotoGP holeshot device work?

Motocross fans will be more than familiar with this term. The holeshot is a line that is marked after the first turn of the race in the Motocross World Championship and AMA Supercross circuits, and serves to reward the rider who makes the best start. At the end of the season, the rider with the most holeshots receives a cash prize. In MXGP, the Spaniard Jorge Prado took this award in 2021, after achieving 18 holeshots in the 35 motos he took part in.

But in MotoGP, the holeshot is something different. It is directly related to the objective, which is to manage to make a good start, and that’s why this device has been familiarly called holeshot.

It was initially quite a basic system that began to be introduced in 2019. The objective of this device was to lower the front of the bike at the moment of maximum acceleration at the start. At that moment, this acceleration is defined by the triangle formed by the force, the height of the center of gravity relative to the asphalt, and the horizontal distance from the point of contact of the tire with the vertical of the center of gravity.

Acceleration capability is improved with this device by reducing the front wheel’s tendency to lift. And the more you accelerate, the higher it goes. Electronic control systems started to be implemented to prevent it, such as the anti-wheelie, which acted on the engine. But what these systems did, in essence, was regulate the power delivery to prevent the front wheel lifting, and logically that intervention affected the acceleration and therefore penalized the start.

Inspired by motocross, where some very primitive systems were used to compress the front suspension on the starting gate, lowering the height of the bike and therefore notably reducing the risk of performing a wheelie that would harm the start, MotoGP engineers sought to do something similar. In Motocross the system consisted of forcing the suspension to engage a pin located in one of the fork legs into a slot in the fork guards. When the first braking arrived, the compression of the suspension was greater, the suspension lowered even more, and the pin was released, recovering the full travel of the suspension.

In MotoGP

Active suspensions are banned in MotoGP, so for the system to work, riders had to compress the suspension through some knobs that they turned before starting and which helped to lower the front suspension, thus reducing the height of the center of gravity. And then, as happened in motocross, when the fork was fully compressed during the first braking, this pressure disconnected the system and the suspension regained its full travel and returned to normal operation.

This system was initially only applied to the front suspension and improved from cumbersome knobs to more comfortable buttons. Then it was implemented by applying the same concept to the rear suspension because lowering the height of the bike at both ends had a much greater effect than lowering the height of the bike at only one point because the center of gravity is significantly lowered.

The MotoGP engineers quickly realized that the benefits derived from the holeshot were not only limited to the start of the race but that lowering the height of the bike on corner exit acceleration is a significant advantage. It is something that was discovered a while ago in Formula 1, active suspensions, but as we said, this system is banned in the MotoGP regulations, which doesn’t allow automatic systems that work with electricity or hydraulic impulses.

The implementation of this system on the rear axle has allowed the acceleration to improve, which is the key in the top speed of a bike. Riders are always asking for more and more power to have greater speed, but there comes a time when so much power is not usable precisely because the momentum that leads to lifting the front wheel means that the benefits of a very powerful engine are lost, and even the electronic control systems do not prevent acceleration from being wasted when they come into operation. Therefore, gaining acceleration efficiency is more important.

 

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Una publicación compartida de Pol Espargaró (@polespargaro)

In essence, a racing bike accelerates most of the time, and only a small fraction of the time does it use its maximum power for maximum speed. A bike spends more time per lap braking than riding at top speed, but most of its time is spent accelerating. That’s why efficient acceleration is the key to everything. And the rear holeshot improves that efficiency.

What must the rider do?

All of this had to be applied, and the rider was directly responsible for doing it. The support systems such as the traction control or the anti-wheelie act automatically when the electronic control panel deems it necessary to intervene. Whether they are more or less intrusive depends on the adjustments that the rider and their technical team have made.

So now, the rider doesn’t just have to worry about opening the throttle, engaging gears, turning… They also had to be aware when lowering the height of the bike, a maneuver that had to be done with precision, because if you anticipated, you ran the risk of lowering the bike while it was still in the lean phase, and given the large lean angles reached in MotoGP, very close to 60°, there was a risk of rubbing the underside of the engine, the exhausts, or the foot pegs. Such dangerous lean could lead to rear wheel lift, loss of traction and grip, and an unexpected understeer that could lead to a crash.

In view of the load put on the rider – with bikes of more than 250 hp and more than 300 km/h – and the danger that this entails, the Grand Prix Commission decided in March 2022 to prohibit the use of the front holeshot in motion during races, with the intention of avoiding further performance improvements and the consequent development cost. However, the rear holeshot and the starting holeshot will continue to be used for the 2023 season.

Many people wonder why the use of active suspensions isn’t authorized, as they are present in many street bikes, but the explanation has its logic. The championship managers want to level the competition conditions as much as possible, which has allowed us to enjoy very exciting championships in the last few seasons, but with an open regulation, the technological implementation would lead the championship to a cost escalation.

In any case, the incorporation of the full holeshot by all manufacturers, like when they all managed to use the Big bang engine, or the seamless gearbox, takes us back to square one. They all have the same weapons. So what’s next, what’s the next technical leap?

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