Combined forces acting against the forward movement of a vehicle is known as rolling resistance. The major part is played by the inertia, gravity, vehicle weight, friction between road and tyre surface as well as the air drag. When you drive a car or ride a bike, it is the rolling resistance that makes you slow down or brings you to halt. The weight of the vehicle, gravity and inertia, the amount of friction between the tyres and the road surface, and air drag all play a part.
Rolling resistance is caused by tyre deformation and is linked with:
- The forces acting on the tyre
- Loss of energy due to heat
The Energy Dissipated As Heat
The shape of the Hankook Tyres London changes when the tyre makes contact with the road. The tyre gets compressed. The tyre casing and the rubber tube parts get heated up as a result of this compression. The tread on the exterior part of the tyre heats up when it makes contact with the road. As compared to smooth tyres, more rolling resistance is present in a tyre having knobbly tread. This is due to the fact that more rubber gets compressed and there is more heat.
The tyre is similar to a rubber band or spring. As the tyres get compressed, it stores some amount of energy. When the vehicle returns to the garage, not much of this energy is left as this has been used in heating the tyre. Hysteresis is the energy loss as a result of heating. This indicates that a very less amount of energy would be left that is not enough to make the vehicle move faster.
This heat is noticed if your tyre temperature can be felt when you drive fast. More heat is produced if the tyres of your car are not inflated hard.
The rolling resistance force is not changed at high speeds. However, more power is used by the car driver to drive against this resistance as more heat is produced at high speed.
Forces on The Tyre’s Front Part Are Greater
A huge amount of force is needed to get the tyre squeezed as the tyre’s front portion makes contact with the road. Thus, a backward force is caused on the wheel by this. A force pushes on the wheel in a forwarding direction when the tyre returns off the road. But, this force in forwarding direction is not that great. This is due to the tyre’s internal friction.
If a tyre could be designed in such a way that the internal friction is absent in it and it doesn’t heat up, the front force in the tyre making contact with the ground would be the same as the back-section force. This would indicate the absence of rolling resistance in which it can be assumed that no energy loss has taken place as a result of compression.
Factors Affecting Rolling Resistance
The weight of the vehicle, tyre design, cornering, and surface of the road and tyre pressure determines the Rolling resistance.
- Weight: More weight indicates gravitational downward force on the road. Rolling resistance elevates as more compression in the tyres occurs. Carrying more load increases the rolling resistance.
- Cornering – The drivers slow down while taking corners as more downward force results from cornering, which elevates the rolling resistance. Moreover, as the rubber of the Tyres London gets twisted sideways while cornering, the rolling resistance increases as more heat as well as friction is produced.
- Road terrain: Less rolling resistance is offered by many terrains. Rough roads offer more rolling resistance. Soft dirt ground and grass are better. Rolling resistance is increased on deformed surfaces.
- Design of tyres – Less amount of rolling resistance is resulted from picking construction and materials that don’t get heated up. Manufacturing the tubes with special latex rubber is an effective way. Racing tyres are pumped hard, narrow and smooth. For minimizing the heat loss resulted from deformation, the casing is designed. With fewer tyres being compressed, very little heat is produced. Hence, more energy is present for high speed. You can have several options to consider.
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