Share

Articles - Archive

06/03/2015
"MUD AND SNOW" VS "THREE PEAK SNOWFLAKE"

Inverno in sicurezza 2015


On the 3rd and 4thof February, in the beautiful setting of La Thuile in Val D'Aosta, winter tires took center stage once again in the traditional event aimed at making authorities and journalists aware on the importance of proper equipment for the winter season. This year’s news was the opportunity to experience firsthand the evolution of winter tires from the simple M+S to the "three peak mountain snowflake"

Luca Ricci

Variable message signs reports of motorways regarding winter tires or signs indicating the requirements of the relevant winter regulations, are a common sight nowadays. In reality, this is the result of a continuous awareness campaign that associations like Assogomma, the tire manufacturers association, and Federpneus have been carrying out for years.

Safety campaigns do not deal only with winter equipment, although this event centered around winter tires has become a tradition. The path chosen is a rather demanding one since it was decided to let both authorities and journalists experience firsthand the differences between the various tire equipments.

The turnout was outstanding, as was the setting, one of the most beautiful places in Val D’Aosta, La Thuile.

Fabio Bertolotti, Director of Assogomma, introduced the event emphasizing that "For the first time this year, we have brought to the attention of the public the fact that there are two types of winter tires with different characteristics, both displaying M+S markings (acronym for MUD & SNOW) able to satisfy all legal requirements. This marking is a declaration on the part of the manufacturer during Type Approval process and can be displayed next to an ideogram of a three peak mountain with a snowflake in the middle, known as 3PMSF ( 3 PEAK MOUNTAIN SNOWFLAKE ). The 3PMSF marking certifies that the tire has passed the Homologation tests set out in the EU regulation 117. Here in La Thuile, it was displayed for the first time to both the institutions and the press”. 

Several tests have compared 3PMSF, M + S and SUMMER tires: in each test and on all types of surfaces, the new concept high performance winter tire, represented by the 3PMSF label, proved to be the best solution.

 

 

How a 3PMSF tire is approved                                

In order to obtain approval, the snow grip index of the tire in question must be at least 1.07 compared to a standard reference tire called SRTT.

Approval tests simulations in La Thuile, were performed with two Fiat 500 Abarth equipped with a set of tires SRTT (Standard Reference Test Tyre), size 195/75 R14 - and 3PMSF winter tires size 185/55 R15 respectively.

A comparative braking test with active ABS was performed. The car was driven up to a speed of 28 km / h, put into neutral and then brakes with active ABS were applied down to a residual speed of 8 km / h. Therefore, the average deceleration was calculated by measuring the distance traveled and the time elapsed between the moment when the speed was 25 km / h to the moment it reached 10 km / h. The test was repeated in order to take into account any changes in the condition of the track.

It was possible to observe the real differences between the two types of tires with a definite advantage for those with 3PMSF markings.

 

 

A different spurt

For the next test a couple of Range Rover Evoque were used, equipped with three types of tires (3PMSF, M + S and SUMMER) size 245/45 R20. A performance test on a flat and snowy surface took place and photocells with “start & stop” functions were placed at the beginning and end of the test section (23m long) in order to measure the respective acceleration times.

Considering 100 the time taken by the 3PMSF tire to cover the distance between the two photocells, the M + S tire took 10% more time to cover the same distance, while the SUMMER tire took 30% more.

 

 

Worthwhile for light transport too!                    

Comparative braking tests in a straight line were also made with two Mercedes Vito equipped respectively with 3PMSF and M + S size 195/65 R16C. These are vehicles with a 3.5 ton mass, quite a load to handle when braking, front wheel drive and diesel power. The objective, in this case, was to show that the vehicle with 3PMSF equipment offers the best performance in braking (distance), and deceleration (road holding), that is, the best conditions in terms of road safety. The test was performed at a speed (50 km / h) typical of urban centers, on a straight stretch of road covered with snow. The different types of tires gave rise to different behaviors of the vehicles. The vehicle equipped with M + S tires, while maintaining a homogeneous behavior, recorded longer braking distances ( between 8% to 20 % more ) compared to the vehicle fitted with 3PMSF tires, in test conditions ranging from -12 ° to -3 °.

 

 

Handling test

The above mentioned were instrumental tests and already showed a clear advantage of tires marked 3PMSF.

Even clearer however was the feeling of greater security while driving in real difficult conditions.

The first test was performed with a couple of all-new Jeep Renegades over a mixed route that started from the village of La Thuile in dry conditions and ended on the San Carlo hill pass completely covered in snow and ice. Those familiar with these places know how treacherous that road can be. This run allowed to test the tires in all possible winter conditions only to confirm what the instrument tests had already shown.

 

 

Always recommend homogeneous equipment        

To demonstrate how important it is to have the same tires on all wheels, the behavior of three Alfa Romeo Mito fitted with tires size 195/55 R16 was compared: a sporty medium/small front-wheel drive car with a petrol engine.

The car equipped with four 3PMSF identical tires offered the best all-round performance ( grip, traction and handling ) that is, the best conditions in terms of road safety. The test was performed at low speed (15-20 km / h) on a straight road entering a roundabout.

The configurations used were: a car with 4 new summer tires, a car with 4 new 3PMSF tires and a car with two new 3PMSF tires on the drive axle (front) and two new summer rear tires.

The vehicles behaved differently according to the different sets of tires. The car equipped with summer tires, while maintaining an overall homogeneous behavior, showed in all conditions problems of grip and handling inducing a very cautious driving style. The vehicle equipped with 4 3PMSF tires, on the other hand, performed without any problem and in total safety. The car with mixed equipment, offered an illusory sense of security on a straight road that disappeared immediately when cornering and braking; the lack of grip on the rear axle could cause a total loss of control and send the vehicle into a spin. The mixed configuration turned out to be the most dangerous because it betrayed the driver when cornering.

It is thus clear that mixed equipment, although not expressly prohibited by law, has to be considered the worst and therefore not recommended, as expressly stated by the Ministerial Directive of the 30th of January 2013.

 

 

Winter tires are essential on 4x4’s too.                          

Retailers know that even 4X4 vehicles require winter equipment, but the La Thuile tests highlighted the superiority of 3PMSF tires over normal M + S even in this type of vehicle.

The test was performed on a really hard terrain, after all whoever drives a 4x4 expects to overcome all kinds of difficulties, and was performed with three Volvo XC60 equipped with 235/65 R17 tires in three different configurations: summer, M + S and 3PMSF. The result? Well, even with a four-wheel drive car 3PMSF tires offer a greater degree of traction uphill. Furthermore, since downhill the advantage of 4x4 traction is somewhat reduced, braking and stopping is directly conditioned by the type of tires used. The test was performed on a snowy path, both uphill and downhill on variable slopes. The vehicle equipped with summer tires failed to get over the first gradient and started going dangerously backwards with locked wheels, completely out of control. As for the vehicle equipped with M + S tires, the test was partially successful, managing to drive over all the different road sections, but struggling when stopping, restarting uphill and in the most extreme conditions. The vehicle equipped with 3PMSF tires, on the other hand, completed the test guaranteeing sprint, traction and braking safety both uphill and downhill.

In extreme conditions, whereas the vehicle with 3PMSF tires came through with flying colors, the vehicle equipped with normal M + S tires needed a nudge or two to get out of troubles. Nothing serious, but it was a demonstration of how this was indeed a real and true test, and not a representation to be used by the authorities and the press.

 

The evolution of the tire continues, and with it the chance to have better safety conditions in the future, but only if the right maintenance procedures are performed.

back to archive