Why are tyres for electric and hybrid vehicles different to diesel and petrol vehicles?
As with all tyres that are designed and ultimately produced, premium tyre manufacturers like Michelin, Continental, Goodyear, Dunlop and Pirelli etc, will design a particular type of tyre for a particular market requirement. For instance, some tyres are developed for small cars that will spend the majority of their life being driven on city roads at a relatively slow speed. Another type of tyre could be aimed at the business driver, who spends a lot of their time driving at higher speeds, up and down the country’s motorway network. Then there is the type of tyre designed for the sports car driver. These tyres will be developed for a more performance style of driving, with high speed cornering and acceleration being the most important factors.
Tyres are specifically designed and produced for SUV and 4x4 vehicles. Some tyres have been developed just for one purpose, for instance, Mud Terrain tyres for 4x4 vehicles that spend all their life being driven off-road in mud, water and boggy conditions. These are the type of tyres you might find on a farmers Land Rover for example. There are All Terrain tyres that have be designed to be a compromise for drivers off SUV or 4x4 type vehicles that want a tyre for use on the road during the working week but maybe go hiking or drive off-road at the weekends.
As you can see, there are many different tyre types that have been researched, designed and developed for differing types of driving conditions and lifestyles.
What should I be looking for in a tyre for an electric or hybrid vehicle?
Well this isn’t an easy question to answer!
With the advent of electric and hybrid vehicles and with these types of vehicles becoming ever more popular and common on our roads, tyre manufacturers have begun to design and develop new ranges of tyres specifically to cater for this increasing market.
Electric and hybrid vehicle tyres throw up a whole different set of requirements to standard road tyres.
Ultimately, it is down to the driver of the vehicle, as to what they see as the most important characteristics in any tyre they are looking to purchase. This is the same for electric and hybrid vehicles, as it is for drivers of the usual diesel and petrol powered vehicles.
Two drivers of the same type of vehicle can be poles apart when it comes to their driving styles and the type of conditions they experience on a daily basis. One of the drivers could have a short city commute to work every morning, while another could have a job that requires a longer motorway journey, to and from work each day and may have to use their vehicle on off-road on occasions or maybe carry a more heavy load etc. As you can see, every driver is different and will be looking for particular requirements from any tyre that they may be looking to purchase. It is not only tyre characteristics! Price is also going to be a factor. A electric or hybrid car driver may know exactly what type of tyre they are looking for but may not have the budget that allows them to make a purchase.
As you can see, when in the market for new tyres, it is really down to the person making the purchase, as to what they are looking for from a particular tyre and what they are able to afford.
Should I be looking at tyre labelling?
Since November 2012, all tyre manufacturers producing tyres for the European car market have been forced to supply all their tyres with EU tyre labelling. This is a labelling display on each tyre showing three different characteristics of that particular tyre.
As you will see from the EU tyre labelling above, there are three ratings for specific tyre properties. Firstly there is the ‘fuel efficiency’ or ‘rolling resistance rating.
This shows how economical the particular tyre is rated. Tyres are responsible for between 20 and 30% of a vehicle’s fuel consumption. As a tyre rolls it uses energy and so a tyre that has a lower rolling resistance will use less energy and this has a direct impact on fuel efficiency and CO2 emissions. Choosing tyres ranked A (best) over tyres ranked G (worst) can reduce fuel consumption by up to 7.5%. This equates to a typical annual fuel saving of 120 litres or £168 (based on 12000 miles and £1.4/l). Currently D is not used on the scale to provide a clear distinction between higher and less efficient tyres.
Secondly is the tyres ‘wet grip’ rating.
Wet grip performance is one of the most important safety characteristics of a tyre. Tyres with good wet grip have shorter braking distances on wet roads. Two types of test are used to measure a tyres grip when braking from 50mph in wet conditions. Results are combined and ranked from A (best) to G (worst) and, like with fuel efficiency, grade D is not used to help more easily distinguish between tyres with shorter and longer braking distances. Each grade equates to a difference in braking distance of approximately 3 meters. Therefore fitting tyres ranked A over those ranked G can reduce braking distance in the wet by 18 meters, which clearly could help avert a road traffic accident.
Lastly is the rating for 'external noise level'.
The inclusion of external rolling noise as a key aspect of a tyre’s performance is to encourage motorists to buy low noise tyres and thereby reduce noise pollution. A microphone measures the rolling noise of a car travelling at 50mph with the engine turned off and the results, in decibels, are given for each tyre. In addition ‘black sound waves’ are used to indicate quieter tyres (1 black sound wave) in comparison to noisier tyres (3 black sound waves). Currently 3 black sound waves is the legal limit, 2 will be a new lower limit to come into effect sometime by 2016 and 1 black sound wave is 3 decibels below this future lower limit. Three decibels may not seem a lot, but it is effectively halving the noise level.
From experience, the external noise level of a tyre has become an increasingly more important factor to take into account for drivers of electric and hybrid type vehicles. This is because the external noise level also affects the internal noise level. With fully electric and hybrid vehicles being driven on battery power only, there is no engine noise, therefore making the noise being produced by the tyres, far more noticeable.
Why can’t I just use standard tyres on my electric vehicle?
Well the simple answer is, you can! There is nothing stopping you having standard road tyres fitted to any type of electric or hybrid type vehicle. When the first electric vehicles began to be produced, there were no specialist tyres being manufactured at that time and all these type of vehicles would come direct from the car manufacturer, complete with standard road tyres fitted. There is nothing different about the way a standard tyre fits to an electric vehicle wheel and using standard, road legal tyres is perfectly acceptable.
However! We have come a long way since the first electric and hybrid vehicles began to be produced. The premium tyre manufacturers have spotted an ongoing and increasing trend in the sales of electric vehicles and would like a slice of that market, rather than being left on the sidelines.
Ever since the first electric vehicles began to be produced, the premium tyre manufacturers will have been pouring millions of pounds into research and development of new tread patterns, tyre rubber compounds and tyre construction techniques. They will have years of information and statistics produced by tyre retailers and consumers on how tyres affect the handling of electric vehicles and how the tyres wear etc. These premium tyre manufacturers will have been striving to produce the best possible tyres for these types of vehicle, in order to get to the point where we are today.
Why don’t the tyre manufacturers produce tyres that are super quiet and A rated?
Well it’s not as easy as it sounds!
It would be easy if tyres could just be produced that were brilliant at everything. As with most things, there is always a compromise. Producing a tyre with exceptional grip, may also affect the noise level of the tyre. Similarly, producing a tyre that has an exceptionally low noise level, may have an effect on the tyres fuel economy. It is a constant battle for the tyre manufacturers, striving to produce the best possible tyres they can, with the technology and materials they currently have at their disposal. Some of these premium tyre manufacturers are using the latest chemical compounds, nylon, polymers, silica and synthetic rubbers in their tyres. Some are even experimenting using materials like moss and seaweed for example.
So what tyres are currently available that have been developed specifically for my electric vehicle?
The short answer is, not that many!
Even though electric and hybrid cars have been around for what seems like a long time now, the technology in these types of vehicle is rapidly changing, and this a constant headache for the tyre manufacturers, trying to keep up with these changes. New models of electric car seem to appear almost on a monthly basis, each one with different tyre requirements. For example, the Tesla range of high performance vehicles, have a tremendous amount of torque going through the wheels and tyres. Because maximum torque is available to the driver the instant the accelerator pedal is activated, the tyre needs to be capable of delivering this amount of torque, safely and effectively. This high level of torque has been found to increase the wear rate of a tyre considerably. Therefore the tyre manufacturers need to develop a tyre that is safe, effective, is designed for high speed driving, has excellent cornering characteristics, low road noise level, while also reducing the tread wear rate. It’s not easy!
Tyres currently on the market for electric vehicles
Here are a few examples of tyres available that have been specifically designed for the electric and hybrid vehicle market. When I say available, it’s not always the case that they are easy to get hold of. Many of the UK tyre wholesalers are slow to catch up with increasing trend for electric cars, and although increasing month on month, this is still only a small proportion of their overall tyre sales.
Michelin Energy E-V
This tyre is the first tyre produced by Michelin specifically for electric and hybrid cars and currently approved for the Renault Zoe.
They claim this tyre has 20% less rolling resistance, giving a 6% increase in kilometres. This is produced by the tyre tread flattening out easily against the road to save energy.
They also claim more lateral tread blocks delivers up to a 40% reduction in internal noise levels. Plus the excellence of Michelin in safety and longevity.
Continental eContact for electric cars
This is Continentals first tyre produced specifically for electric vehicles.
They claim the tyre has minimal rolling resistance for the highest mileage. Unrivalled braking performance of low noise emissions and an aerodynamic sidewall, designed with a golf ball structure.
At the Geneva International Motor Show, Goodyear unveiled their new EfficientGrip with electric drive technology. This tyre should be available sometime in 2019 and has been designed specifically to reduce treadwear for the heavier and more powerful electric vehicles that have instant high torque.
Making an informed choice
Ultimately it is down to you, which tyres you decided to have fitted to your vehicle. Nobody knows your driving style, the type of journeys you take and what characteristics you are looking for in a tyre better than you do. The premium tyre manufacturers are trying to keep up with current trends and demands and are beginning to produce excellent designed tyres specifically aimed at electric and electric hybrid type vehicles. As with most tyre trends, it is expected that more tyre manufacturers will come on board and produce their own range of tyres for the electric car market and these tyres will eventually be a common sight on our roads.
For more information on car tyres for electric and hybrid vehicles, please visit www.allabouttyres.co.uk
