How Does Hysteresis Affect Rolling Resistance and Tyre Efficiency?

Hysteresis effect in tyres. An important phenomenon in vehicle dynamics and tyre engineering occurs in a cyclic load condition called the hysteresis effect of tyres. In plain words, hysteresis is the energy loss that the material of the tyres would experience under the influence of inner friction as the tyre would deform and then recover again every time it rolls. As a tyre revolves, constantly shifting sections of tread and sidewall are forced and released as they make contact and become detached from the road surface.

The result of this repeated mechanical deformation is internal strain in the rubber compounds of the tyre, creating friction at the molecular level. Heat is produced by this friction, and this friction is called the effect of hysteresis. In contrast to an ideal elastic material, in which only the direct path in the deformation-recovery cycle is used and no energy is dissipated, a looped stress-strain curve is observed in the real tyre materials (which are viscoelastic).

The energy that is lost in this total cycle is shown in the region within this loop and is lost mainly in the form of heat. This energy is not used to propel the vehicle, hence a kind of uselessness called rolling resistance. It has a high impact on fuel or battery usage, especially on long journeys or at constant high speeds, and is therefore a major area of interest in reducing vehicle usage.

Energy Loss and Rolling Resistance Contribution

On pneumatic tyres, hysteretic energy loss contributes much to rolling resistance. The force acting against the movement as a tyre runs across a surface is called rolling resistance, and it contributes about 5-15 per cent of overall fuel use in internal combustion engine vehicles (ICEVs) and even higher in electric vehicles (EVs) because they require much more power to be energetically efficient.

Any time the tyre undergoes the process of deformation on the road, part of the mechanical energy becomes converted into heat due to the viscoelastic characteristics of the rubber in the tyre. In cases where the performance and efficiency of the vehicle need to be optimised in urban or even high-mileage conditions, the use of high-quality Car Tyres Warrington that have been designed to minimise hysteresis losses can make a significant difference.

The energy wasted in the tread area translates directly to the decreased efficiency of the vehicle, as the engine or electric motor has to provide more energy to keep the vehicle at speed. The rolling resistance of the tyre may also vary with temperature as it heats up, as the rubber compounds become less elastic.

Such total energy loss has not only an impact on fuel consumption but also influences tyre wear and tyre heating up, which shortens material properties and lifetime. Therefore, it is essential in economic and environmental terms to learn how to reduce hysteresis losses.

Minimizing Hysteresis through Optimization of Tyre Compounds

The solution to minimising the loss of energy caused by hysteresis is in optimising the tyre materials used specifically in the production of the rubber compounds of the tread and sidewalls. Conventional rubbers poured with carbon black are rugged and exhibit very good traction, albeit at a higher hysteresis loss. Silica-based compounds, on the contrary, have been a game changer in cutting rolling resistance.

Silica reacts differently with rubber polymers, such that they undergo less energy loss under cyclic deformation but still have acceptable traction and flexibility. Moreover, the introduction of more advanced mixing technologies and coupling agents can assist in bonding silica more efficiently with the rubber matrix to increase the performance of the material when exposed to dynamic loads.

One growing challenge within the field of tyre engineering is the development of a balanced tyre compound that decreases rolling resistance without compromising the grip and, in particular, your chances of gripping in wet (wet grip) conditions. Now, manufacturers are getting to use non-materials, bio-based fillers, and polymer blending processes to engineer rubber properties on the micro level.

Efficiency and Grip in Tyre Design

Although it is necessary to reduce hysteresis to achieve high fuel economy, this should not be done at the expense of the tyre grip, particularly in those safety-sensitive cases. Grip mostly depends on the capability of the tyre to shape to the road and ensure friction, especially during dynamic loads such as braking or sudden steering.

A very low-hysteresis tyre may roll more efficiently; however, it has less surface adhesion and slower recovery of deformation, which decreases traction. In striking the balance, tyre manufacturers employ structural design as well as compound engineering. An example is the multi-layer tread where a low-hysteresis base layer is under a high-grip cap layer. The base assists in rolling resistance, and the cap creates the appropriate traction performance.

In like manner, a higher tread pattern design is also a factor by nature that helps redistribute stress more evenly and avoid excessive deformation. Also, by stiffening the tyre carcasses and the sidewalls, the tyre designers can reduce unnecessary energy loss during lateral and vertical motion without making the ride too hard. Hysteresis is also optimised by tyre pressure monitoring and inflation; underinflated tyres deform more and, in effect, generate more hysteretic losses.

Thus, fuel efficiency and grip balance can be maintained by observing maintenance. In battery-powered cars, where rolling resistance is extremely important to range, automakers do go so far as to create electric vehicle-specific tyres, taking into account the peculiar weight distribution and torque profile of electric cars. The comprehensive approach facilitates this priority and makes energy efficiency and safety a priority even during strenuous driving conditions.