Hankook Enfren Low Rolling Resistance Tyre Launch
Would a day at the race track disprove my thoughts on LRR tyres?
-by Matt Brogan
Low Rolling Resistance tyres may sound like an oxymoron, and quite often the assumption made is that an LRR tyre will not perform as well as a conventional steel belted radial in terms of grip, stopping performance and cornering capability.
So when Hankook released its latest Enfren range of LRR (Low Rolling Resistance) tyres yesterday it seemed logical that the best place to disprove that theory was obvious – Sydney’s Eastern Creek Raceway.
But before we get in to that, just what is an LRR tyre, and why is it so important to know that they have become the next big thing in tyre technology.
Well the answer in this case lies within the name “Enfren”. It’s short for Environmentally Friendly, and while this may not be an inherent character of a tyre as such, the improvement the technology within this tyre makes to a car’s overall environmental performance certainly is.
The way in which this is achieved, as you might by now have deduced, is to minimise the coefficient of the rolling resistance of the tyre.
Rolling resistance is created when, as a tyre rotates, vehicle weight and gravity combine to pull the car downward slightly deforming the tyre and creating heat.
To overcome this physical challenge Hankook have combined silica and rubber together – in specific quantities – along with a few other compounds to give the tyre less friction while at the same time redistributing the resistance forces within the tyre to reduce energy loss.
But don’t confuse friction with grip because, as we discovered yesterday, in designing the tyre’s compound and structure to behave differently in its correlation to ground contact has not only assisted in improving the rolling resistance of the tyre, but has also allowed a greater surface area contact with the road which has actually improved ‘grip’ as we know it.
To put this to the test we were given a number of Hyundai i30 and Sonata vehicles shod with Enfren tyres and put through a series of tests aimed at demonstrating the capabilities of tyre load, grip and traction in specific circumstances.
First up a wet slalom run at 80km/h allowed us to assess the tyre’s wet weather grip via sudden directional changes. The test proved conclusively that the Enfren LRR tyre performed just as well as the standard tyre in similar conditions with no discernible difference in grip noticed.
Next we accelerated hard through a corner with a tightening apex (Turns Two and Three) as we continued to increase speed. The aim here was to determine if dry grip, and the ability for the car to hold its line (i.e not understeer), was the same with LRR tyres, and again, there was no discernible difference.
By now I have to say the cynic in me was becoming a little displeased so on Test Three I was determined to try a little harder when faced with a corner slalom.
The idea here is to negotiate a slalom while travelling through a corner. As such the car is off balance at least half the time.
Again, the grip was as good as a conventional tyre and despite my best efforts I could not get the car to lose direction stability with only a hint of understeer detected.
Our next test involved progressiveness whereby a series of chicanes (placed strategically between Turns Seven and 10) were intended to unbalance the vehicle to the point of losing grip. Surprisingly the side wall carried the high lateral loads well with grip maintained well before any electronic assistance was required.
So by now I’ll admit I was just a little impressed. The tyres were coping well, at least as good as any conventional tyre, but I was keen to go one step further and assess wet weather braking.
As the track was damp, but not really wet, Hankook kindly flooded the skid pan area at the back of the circuit to allow one final test.
In completing an emergency stop from 80km/h the results show that the Enfren tyre actually stopped in a shorter distance than its conventional competitor proving that through each of our five tests I was left with no reason to doubt the tyre’s performance.
Unfortunately the day’s environmental undertones didn’t allow me to perform a “smoke test” but I’ve got to say I am sold on LRR technology and would be very keen to try them out long term. If all other indicators are the same longevity should prove equally impressive.
Enfren Low Rolling Resistance tyres are available in most popular sizes through Hankook stockists.