How to Cornering a Motorcycle - Part 1

The question that all riders, professionals or amateurs, all MotoGP technicians, and all enthusiasts ask themselves: How do I make the bike turn?

The effectiveness of a bike in cornering has always been a fundamental issue in motorcycling. As complex as it is difficult, a preliminary answer must be given: there is no single answer to the problem! This somewhat disappointing response is due to the natural consequence of the complexity of the motorcycle’s dynamics when cornering.

But then, is there no guideline for building, setting up, and riding a motorcycle? Luckily, no. Over the years, motorcycle technology has built up the essential experience that today provides us with an awareness of how the bike works when cornering and has also brought a remarkably high level (and high driving pleasure) to road products.

Despite this, what remains an open topic to this day is the difficulty of fully exploiting the vehicle’s potential without falling (a limit often exceeded by professional riders).

So, let us see the factors involved to understand how a bike works when cornering and how we can control and modify its behavior to adapt it to our needs.

To begin, we will divide our analysis into two phases: first, we will see the technical aspects of the motorcycle that participates in the vehicle dynamics, and secondly, we will explore how a rider can intervene to make their bike turn like a pro rider.

Rule One: It All Depends On The Tire!

The fundamental point that must always be taken into account is the centrality of the tire. In fact, it is the only thing that keeps the vehicle in contact with the ground. Through it, it can exchange the forces necessary to make the bike accelerate, slow down, and turn.

In addition, the tire consists of two elements: the carcass and the compound. The carcass is the load-bearing structure of the tire (which is mounted on the rim) and is composed of metal and plastic bands that give the tire its profile and structure. The compound is vulcanized on top of the carcass in a softer material that, thanks to its properties, can generate a grip on the asphalt.

All, and I mean all of the motorcycle’s design, must be done based on the tire. Just think of how the tire supplier changes in MotoGP are a symptom that even the slightest differences in the tire level induce significant differences in the vehicle to achieve the same performance (remember the switch from Bridgestone to Michelin when the bikes were upset when adapting to the characteristics of a different tire).

Rule Two: The Design Of The Motorcycle

But what does it mean to make the tire work correctly?

This means guaranteeing the tire has the correct shape of the contact patch to the ground, the right vertical load, the right temperature, and the right drift angle in all driving conditions and every driving phase.

To do this, designers worldwide focus on setting vehicle layouts so that the masses of the bike guarantee a particular load distribution between the front and rear and a certain height from the ground of the center of gravity (which affects load transfers).

Once the vehicle layout has been determined (considering the size of the engine), we then move on to the design of the frame with all its fundamental parameters: casters, offset, pivot, chain pull, etc.

At that point, we move on to the design of the suspension, superstructure, and (for prototypes) we work a lot on the aerodynamics, which can offer substantial benefits in terms of vehicle dynamics.

There are also an infinite number of parameters that influence the vehicle’s behavior. However, at this time, it is essential to remember the fundamental rule (which will be the rider’s mantra): Any modification, to be helpful, must allow the tire to work at its best. All the rest are urban legends.

Rule Three: The Rider On The Bike

We now come to the second part of our analysis, namely the interaction between humans and motorcycles. Unlike the car world, where the driver, from the point of view of vehicle dynamics, represents a mass to be considered, on a bike, the rider must actively participate in the evolution of the vehicle’s configuration in the various phases.

For example, the rider’s position on the saddle determines a particular equilibrium configuration for the vehicle in the cornering motion; therefore, the correct position determines the correct operation of the tires. In general, it is possible to state that the center of gravity of the motorcycle-rider system must always be aimed at maintaining the maximum footprint on the ground with the least possible lean angle. That is why we see MotoGP riders leaning very clearly towards the center of the corner.

Nevertheless, the exact posture is entirely personal (just look at how far Marquez leans out from a rider like Rins, who is defined as belonging to the old school. However, both are effective on the track). In general, however, the seat must be on the “edge” of the saddle on the inner side of a turn, the shoulders must be carried with the front loader with a slight twist of the torso that brings the external shoulder towards the internal handlebar, with the arm exterior embracing the tank. The head will then go directly to the chord of the curve.

On closer inspection, the head is the essential element from which all the other specific postural settings will then descend; in fact, the bike will go where we are looking.

In addition, the forums often talk about counter-steering being induced to make the bike go down effectively. This is a bit of a myth and a bit of the reality of motorcycling. Since my first experiences on the track alongside professional riders, I learned that counter-steering is not something to look for when making the bike turn. However, it is a consequence of a correct posture.

The bike will automatically go down in the corner the best way by positioning the head, shoulders, pelvis, and legs as described. The steering will feel that resistant force, which we will find ourselves contrasting naturally (without forcing but accompanying).

This resistance derives from the tendency of the motorcycle to persevere in its state of motion (the gyroscopic forces of the wheels and the engine counteract the vehicle’s lean). Therefore, exerting a force on the handlebars while maintaining an incorrect posture will be useless and, above all, dangerous because it will bring the bike to a lean angle, which is impossible to deal with when keeping a straight posture, resulting in the risk of falling.

Instead, by setting the correct posture, we will find ourselves following the descent in the lean towards the chord of the curve. We will then feel the tire working correctly, perceiving the famous feeling of the front.

Rule Four: Throttle-Brake Management

The last important question is how the management of the throttle and brakes (and clearly of the gear changes and all the rider’s operations while driving the vehicle) affects the vehicle’s dynamics.

Firstly, neutral phases are to be minimized on the track. In fact, phases in which the bike does not accelerate and brake are phases in which you are usually recovering from an error or you do not have the confidence to push.

Therefore, a perfect lap should always have very limited neutral phases, if none at all.

Arriving from a straight at full throttle, with a completely collected posture to reduce the front area exposed to the air and set back as much as possible to load the rear in acceleration, you are preparing to brake by looking for the outside of the track, exiting the aerodynamic protection of the fairing while you proceed to brake.

With motorcycles equipped with steel brakes (for carbon-fiber brakes, it is a different braking style), it is vital to attack the brake immediately and then apply the maximum braking pressure to lower the front fork and load the front tire. Also, thanks to the load at the front, it will be possible to maximize deceleration by being able to brake as late as possible.

The entry phase also coincides with the decrease of the braking pressure (non-release of the brake, which will take place only in the apex of the corner) and the progressive descent into the lean (allowed by the posture of the driver who begins to move towards the inside of the corner).

When approaching the center of a curve, the braking pressure will reach close to zero, and the fork will reach maximum travel. Therefore, as soon as you let go of the brake, it should be possible to go on the throttle immediately (the secret is always to delay cornering, you will have less entry speed, but it will be possible to prepare the exit of the corners better, and for high power bikes and amateur riders, this sharp style is more profitable).

Similarly, the throttle will gradually increase as you start to raise the bike, and as soon as the bike is below 15-20 degrees of lean, you can open the throttle.

For this first episode on the cornering of a bike, we will stop here, and we hope we have given a base to our fans. In the next episode, we will go deeper into all the details mentioned and not mentioned in this article to allow those who want to deepen their knowledge and find the most hidden secrets of motorcycle vehicle dynamics.