How well do you know the tires used on your DIY electric car? Green product, fuel saver and low rolling resistance, these are all the jargon used when you are introduced to tire designed with silica.
Generally, they all are fundamentally the same thing and refer to performance and advantages achieved by adding silica to the tread compound of tires. Yup, it is pretty technical stuff and the significant advantage of adding silica is reduced drag and at the same time maintaining performance and essential qualities such as wet grip. In other words, the tires are safer and you can reduce the discharge rate of the batteries on your homemade electric vehicle (EV).
Tires containing silica have been in the market for over a decade. Where silica has actually been widely used in tire design plans since last few years or so. The use of silica is today widespread.
Use of silica by leaders such as Michelin in the Michelin Energy and Continental in the ContiEcoContact CP and EP tires was considered to be an actual breakthrough in tire technology.
Question is why low rolling resistance tires are so revolutionary in design and how does a consumer benefits from what it offers? Solving the compromise is a major problem that is faced by tire designers who have traditionally solved the compromise between low rolling resistance and wet grip.
Rolling resistance is the amount of energy a tire absorbs caused by revolving and deflecting. The lower the rolling resistance the lesser the energy needed propel the vehicle forward thus lower power consumption from the electric motor.
However, lowering the rolling resistance has traditionally meant a reduction in wet grip performance which obviously is unacceptable. What’s the use of having power in the battery bank but you’ll end up in a ditch every time you take a corner in your EV?
This problem has been worked out by replacing certain quantities of carbon black with silica in the tire’s tread compound which enables manufacturers to produce tires that provide wet skid properties, better winter performance and lower rolling resistance, all at the same time. All in all, it is a good thing!
The reason why this technology has been considered to be revolutionary is best described as follows: Grip is affected the degree at which a tire is distorted at higher frequencies, in other words the degree to which it hits the small stones and unevenness on the surface of the road.
Grip is also served by rubber compounds that absorb higher level of energy (high hysteresis compounds). Rolling resistance, on the other hand is affected by low frequency distortion that is the deflection of tire as it revolves. It also requires compounds which absorb low quantities of energy (low hysteresis compounds).
This contrast is the reason to why it has been impossible in the past to provide tires which can reduce rolling resistance and increase in wet grip. Again, it is very technical but kind of interesting if you are a science freak.
Tire engineers however have been able to produce compounds which are high hysteresis at high frequencies and low hysteresis at low frequencies with the addition of silica. The use of silica can cause a reduction in rolling resistance by 20% and more.
Assuming correct tire pressures are maintained and making allowances for changing speeds together with different driving characteristics, a 20% reduction in rolling resistance equates to 5% fuel savings on conventional gasoline driven automobile.
The use of silica can also improve wet skid performance. By adding silica to their winter tire range, Vredestein claim to have improved wet skid performance by 15% and at the same time substantially improving, braking distances.
Silica also provides substantial benefits with winter tires and all-season tires. Compounds using silica are more elastic and flexible at lower temperatures that allow better grip and braking during cold weather.
Therefore, when you are looking for a new set of tires for your electric car, get the type with silica designed. With this type of tires, you can extend your EV effective driving mileage and much safer at the same time.
DIY Electric Car Conversion Manual
If you are looking for a good Do It Yourself (DIY) electric car conversion book, check out Gavin Shoebridge’s Electric Conversion Made Easy guide.
Gavin is from New Zealand and he has converted his old 1987 Mitsubishi Treadia into a pure electric car in his garage.
Gavin is also well known in the homemade electric car realm. This is because of all the videos he took when he was converting his Tredia to EV.