The Nokian WR G2 is an All-Season police tire with a Severe Snow rating.
During the 2011 Michigan State Police Tire Tests, the Nokian WR G2 “All-Weather +” tire performed as well as the best All-Season police tires from Goodyear and Firestone. The Nokian brand is better known by fleet managers in the northern states and Canada than by their counterparts in the southern states. In snowy regions, Nokian is downright famous for their Hakkapeliitta winter tires. (Hakkapeliitta is a famous Finnish battle cry.) In 1936, Nokian produced the world’s first “winter” tire. Today, Nokian tires hold the world’s top speed record on ice.
The best kept secret about Nokian is that they also make All-Season tires. Of course, the Finns don’t call them All-Season — that is a North American concept. (It requires no testing whatsoever to be labeled an “All-Season” tire.) The European market has only two types of categories for tires: summer tires and winter tires. For winter tires, there is a performance test…you have to earn the Snowflake-on-Mountaintop icon.
True All-Weather Tire
The WR G2 fits both tire categories, so Nokian calls it an All-Weather + tire. In fact, it is a summer (All-Season) tire with the Snowflake-on-Mountain (Severe Service) snow rating. The WR G2 can be run all year around in snowy regions, unlike the OE All-Season police tires. Nokian lists the WR G2 on their website under both summer and winter categories. The initials WR G2 means Winter Radial Gen 2. It was launched in Europe in 2007, so it has had lots of street time.
It may come as a surprise even to the fleet managers familiar with Nokian winter tires how competitive these Nokian summer-winter tires were during the MSP’s All-Season tests against the best police tires made. Let’s take a closer look.
From the MSP test results, it is possible to directly compare the Nokian WR G2 on dry and on wet pavement to the Goodyear Eagle RS-A on three cars – the Ford CVPI, Chevy Impala and Chevy Caprice. On one sedan – the Ford CVPI – it is possible to directly compare the Nokian to both the Goodyear and the Firestone Firehawk GT Pursuit.
The averages of the three-sedan results show the Nokian WR G2 out-performed the Goodyear Eagle RS-A in four out of six categories: wet braking, wet brake-and-turn, steady-state cornering, and road course lap times. In two categories, the Goodyear bettered the Nokian: tire wear and dry braking.
In the admittedly small “sample size of one” with the Ford CVPI, the Nokian split the results with the Goodyear and Firestone. The Nokian turned in the best wet braking; the Goodyear did the best in tire wear and lap times; the Firestone took the dry braking, wet brake-and-turn, and steady state cornering stages. Put another way, the Nokian was first or second in five out of six test stages on the Ford CVPI.
Running nose-to-nose with the best two All-Season police tires — in a classic All-Season (dry and wet) tire test — is a major accomplishment for Nokian. The punch line — the Nokian WR G2 is also Severe Snow-rated, while the Goodyear and Firestone are not. The Snowflake on Mountain embossment on this Nokian tire is proof of that.
Unlike the M+S icon, which is design-based but not testing-confirmed, the Snowflake-in-Mountain icon is performance-based. In a winter season-oriented test protocol, there is no comparison between the Nokian and the other police tires. (See the sidebar on All-Season versus Severe Snow.)
We conducted a long-term driving evaluation on a set of Nokian WR G2 tires. They hit the pavement the beginning of January, right in time for the first heavy snow of the season. The evaluation continued through the downpours of a Midwestern spring, followed by the heat of summer – a real “all-weather” road test.
The road surfaces varied from interstates, to state roads, to gravel country roads. During the winter, we drove on snow-covered, hard-packed snow and ice with combinations of salt-sand, sand-only and no surface counter-measures at all. And we frequently drove as aggressively…as if we were testing tires.
The wet traction (accelerating, braking and cornering) was outstanding, clearly superior to the All-Season police tires. Our driving experience over six months confirmed the numerous controlled tire tests. This Nokian All-Weather tire is all about wet weather performance. We could feel it during aggressive starts, hard stops and aggressive cornering. The ABS, traction control and stability control kicked in less often than with other All-Season police tires. If your current police tire is slippery when wet, the WR G2 is the answer.
Likewise, the hydroplane resistance was outstanding. Hydroplane, of course, is a function of tread depth (or water depth) and vehicle speed. Even still, nothing moves water out of the way better than a snow tire designed to move slush out of the way. The angular tread blocks in the inner part of the asymmetric tread pattern move water away from the footprint.
The dry traction (accelerating, braking and cornering) during the warmer temps was average for an All-Season police tire. ABS controls dry braking, traction control limits dry wheelspin, and the overall traction on dry pavement is obviously better for any tire than dry pavement. The only obvious dry traction driving impressions are from steady-state entrance and exit ramp cornering and aggressive turns at intersections.
In the warmer spring and summer, the WR G2 had the same dry traction as the OE All-Season police tires. We could not tell any difference. In temperatures below 32 deg F, however, the Nokian had better dry traction than the All-Season tires. The ABS and traction control were activated less during hard stops and quick starts under these dry but cold conditions.
Likewise, under dry and warm conditions, the steering response (the overall handling) from the Nokian was average for an All-Season police tire. The turn-in response, and response to evasive maneuvers was the same as OE All-Season police tires under warm temps, but noticeably better under freezing temps.
The light and deep snow traction was outstanding, of course. With the Severe Service snow rating, the WR G2 clearly separated itself from any All-Season tire. From light snow, to snow that was deep enough to scrape the radiator air dam, the WR G2 acted like a true “snow” tire. On hard-packed snow, the traction was slightly better while braking and accelerating than an All-Season police tire. However, nothing except studded tires works really well on hard-packed snow or ice.
As for ride comfort, there was no vibration or harshness at all. The WR G2 had a driving smoothness equal to any All-Season tire. The Nokian tire was slightly noisier than the average All-Season tire, but you would have to be driving a Cadillac to tell — not an Impala.
We recorded tread wear knowing the only way to properly judge tread life is to try a set on a couple of your patrol vehicles. The tires were not on a dedicated traffic unit, which would get the most aggressive use. Instead, they were on an admin vehicle, which gets wear and tear similar to most calls-for-service, patrol vehicles.
During the 6-month evaluation period, we put 7,000 miles on the tires. At that point, the tires still had 75 percent of the tread remaining. Being very familiar with both the Eagle RS-A and the Firehawk GT Pursuit, the Nokian WR G2 seemed to have about the same tread wear under the same driving conditions.
One of the great outcomes of the 2011 MSP tire testing is to give well-deserved exposure to the Nokian brand of tires. The tire experts in Finland clearly do summer tires (true All-Season) as well as they do winter (dedicated snow) tires.
MSP Police Vehicle Tire Evaluation
Average of Results from Ford CVPI, Impala and Caprice
Eagle RS-A WR G2
60 mph Dry Asphalt Braking 144.9 feet 152.7 feet
35 mph Wet Jennite Braking 105.7 feet 99.8 feet
40 mph Wet Braking in Turn 80.3 feet 77.7 feet
Steady State Turn (w/o ESC) .94 g .98 g
Wear Sequence Lap Times 63.4 sec 63.0 sec
Percent of Tire Worn in Testing 36% 40%
Results from Ford CVPI only
Goodyear Nokian Firestone
Eagle RS-A WR G2 Firehawk GT
60 mph Dry Asphalt Braking 140.4 feet 148.3 feet 137.9 feet
35 mph Wet Jennite Braking 112.6 feet 103.5 feet 106.6 feet
40 mph Wet Braking in Turn 83.7 feet 77.6 feet 71.1 feet
Steady State Turn (w/o ESC) .92 g .97 g 1.0 g
Wear Sequence Lap Times 62.5 sec 62.7 sec 63.0 sec
Percent of Tire Worn in Testing 38% 45% 60%
So, What Does All-Season Mean, Anyhow?
…the M+S rating versus Severe Snow rating
Virtually every All-Season tire is a Three-Season tire. That can be quickly confirmed by any patrol officer facing even light snow on the typical All-Season police tire. For most tires, All-Season means Spring-Summer-Fall conditions. It definitely does not mean Winter conditions. The best response to the freezing and snowy season is to take off the All-Season tires and put on true Winter tires…the ones with the Severe Snow icon embossed in the sidewall.
Tires are a complex compromise of wet / dry traction, of hot / dry and frigid / snow performance, and wear / cost. That said, one of the most elusive goals is finding an All-Season tire that really is an “all-season” tire, in other words, it is also a true Winter tire. And it also needs to be speed-rated for police work. And available in police sizes.
Mud & Snow Versus Snowflake
So, what does the All-Season designation really mean? All of the All-Season police tires are rated M/S, M+S or M&S, that is, “Mud and Snow.” This is a very misleading term. Established by the Rubber Manufacturers Association (RMA), the M+S designation refers only to the tread pattern. The M+S standard calls for a tire with grooves at the outside of the tread that extend into the center.
The M+S standard also means that 25 percent of the tire tread contact surface be open, i.e., a more open tread pattern. However, there are no performance standards to meet or traction tests to pass. Any tire with grooves through the tread blocks and 25 percent of the tread void can be labeled as M+S.
So, what makes a true Winter (snow) tire? In 1999, the RMA established a real-world performance test in snow to define a real Winter (snow) tire and to earn a Severe Snow rating. The Winter tire must provide traction at least 10 percent better than a standard reference test tire. Tires that pass this performance test are embossed with a Snowflake on Mountaintop icon. The typical All-Season M+S tire cannot pass this test, i.e., the M+S rating doesn’t mean much. The Severe Snow rating with its Snowflake on Mountaintop icon really means something.
A tire with the Severe Snow rating has three major advantages over a typical All-Season tire. The single most important aspect is a tread compound that remains soft at lower temperatures. Under lower temperatures, the rubber in the All-Season tire gets hard. A Winter tire compound remains soft and pliable at lower temperatures. The differences in braking and cornering — on dry roads — start to be seen at temps below 45 deg F.
The second major advantage is due to the sipes, or tiny slits in the tread blocks. These are not the grooves or gaps or channels in the tread. Instead, they are cuts or slices in the tread blocks. An All-Season tire may have a few sipes in the tread. However, the Severe Snow-rated tire has so many sipes, this feature alone visually defines most of the tires with this performance rating.
The sipes play a major role under wet snow, icy snow and mirror ice conditions. Up to 50 percent of tire performance under these three common winter conditions comes strictly from the sipes! They are also designed to close and turn their tread block solid during cornering. Under some conditions, the snow-packed sipes offer more traction than the grooves in the tread. The police speed ratings cannot be achieved with aggressively spaced tread blocks. At these higher speeds, the Severe Snow-rated tire performance comes almost exclusively from the sipes and rubber compounds.
The third and most obvious design difference of a tire that has earned a Severe Snow rating is the tread block design, i.e., open grooves and aggressive, more angular or curved tread patterns. On packed snow, the effect of the tread pattern is 40 percent, the compound adhesion is 40 percent, while the sipes contribute 20 percent. Under wet snow conditions, the tread grooves, compound adhesion and sipes effect all contribute 33 percent of the resulting traction.