How much does rolling resistance affect mileage?

When it comes to tyres, one of the phrases you will probably hear frequently during discussions is "rolling resistance". But what exactly is it, how is it measured, and what does it mean in terms of how Protyre's tyres perform?   

What is rolling resistance? 

  Rolling resistance refers to the resistance experienced by a tyre as it rolls over a surface and the amount of energy that is needed to overcome this.    

What causes rolling resistance? 

  There are several causes of this resistance - notably tyre deformation, friction, and wing drag.   

How is it tested?  

There are numerous ways to measure rolling resistance, but the most common method is the drum test.   

A central drum is used to drive the tyre, whilst various force sensors are placed in the middle of the tyre. The machine then applies a load onto the Protyre tyre whilst the drum is forcing it to turn. The force sensors are used to determine the amount of resistance that the tyre needs to prevent it from turning. This is a fairly straightforward and accurate way of measuring rolling resistance. 

How is rolling resistance expressed?  

Rolling resistance can be expressed as either kilograms per ton or given as a coefficient known as N/kN (Newtons over kilo Newtons).     

A low coefficient means a lower level of energy is needed to overcome the resistance. This also means that less fuel is required and lower emissions are generated.   

How to check the rolling resistance rating of your tyres   

The standard EU tyre label features a rating for rolling resistance, but it is usually referred to as the fuel-efficiency rating. This is because the lower the rolling resistance, the more fuel-efficient a tyre is. These ratings range from A through to E, with A being the most fuel efficient/having the lowest rolling resistance.    

You can get a free tyre check at any of Protyre's 180+ garages to see the rolling resistance rating of your current tyres. 

What affects the rolling resistance of tyres? 

  The rolling resistance of a tyre is determined by a number of factors, including, but not limited only to tyre design, tyre tread, tyre pressure, load quantity, load distribution, road surface, and the weather/climate.    

What impact does a tyre's rolling resistance have? 

The key impact of rolling resistance is the effect it has on fuel consumption and mileage. The lower the rolling resistance of the tyre, the less energy and fuel it needs to keep moving. Driving a car that has tyres with high rolling resistance would use comparatively more fuel than driving one with low rolling resistance Protyre tyres, assuming the same car in the same conditions.    

Who benefits most? 

Tyres can account for as much as 30% of a car's fuel consumption. Therefore, drivers who cover a lot of miles will benefit the most from tyres with lower rolling resistance as they will save more in fuel. Additionally, drivers of electric cars will benefit significantly as it will help to extend the battery range in terms of mileage per charge.    

How does it affect mileage? 

Rolling resistance affects mileage more than you may realize, but it is usually only noticeable when the tyre's ratings are different. You may not notice a difference if switching from one make of A-rated tyre to another, but you would notice one if switching from an A-rated to a C-rated Protyre tyre.   

Which tyres have low rolling resistance? 

We have established that low rolling resistance is a good thing. So what are some of the best low rolling resistance Protyre tyres on the market?    

-Michelin CrossClimate 2    

-Bridgestone Ecopia EP422 Plus 

-Firestone Champion Fuel Fighter 

Buy new tyres online or visit your nearest Protyre garage for expert advice. As our name suggests, Protyre are the tyre experts with the UK's largest online tyre stock. All Protyre garages are staffed by experienced and qualified fitters to help you choose the perfect tyres for your needs.