02 · The test numbers

What the Tests Say: Ice, Snow, Wet and Dry

The clearest comparison we found puts all six kinds of tire through the same tests, all from one maker so the brand doesn’t muddy things. Tire Reviews tested six Nokian tires in Finland: snow and ice at about −15°C, wet and dry at about +15°C. Shorter is better.

What that means for you

• On ice, it isn’t close. The Nordic winter tire stopped in less than half the all-season’s distance, and studs shaved off about 10% more.
• In snow, all-weathers hold their own. The all-weather matched the European winter tire and was close to the Nordic one. The all-season needed 70% more room.
• On warm, bare pavement, the order flips. Soft winter rubber and studs stop longer on wet and dry roads at +15°C, which is exactly why you take them off in spring.
• Summer tires own warm roads, and fail in winter. The summer tire stopped shortest of all on wet (27.1 m) and dry (25.6 m) pavement, but needed 98.6 m in snow and couldn’t even be tested on ice.

North American tests point the same way. In Consumer Reports testing, winter tires accelerated from 10 to 30 km/h on packed snow in 19.5 metres, against 26 metres for all-seasons, and stopped about 1.8 metres shorter on ice. CARFAX Canada says that from 50 km/h, winter tires stop about two car lengths sooner than all-seasons.

04 · Track tires

Road-Legal Slicks: What to Run If You Take Your Car to the Track

First, a reality check: true racing slicks have no tread at all, and no DOT marking, so they aren’t legal on the road. What people call “road-legal slicks” are DOT-stamped tires with just enough tread to pass the rules. They come in two flavours, and both are summer tires taken to the extreme.

200-treadwear “extreme performance” tires, like the Bridgestone Potenza RE-71RS, Yokohama Advan A052 and Falken Azenis RT660, still look like street tires and you can drive them to the track. R-compound (DOT competition) tires, like the Toyo Proxes R888R, Nitto NT01 and Hoosier R7, are semi-slicks with only a couple of grooves and a treadwear rating of 100 or less. They’re faster again, but they’re really race tires.

Track-focused “Cup” tires blur the line between street and race rubber.

Before your first track day

• Heat cycle new tiresThe first session countsHoosier recommends keeping the first session on new R7s to 10 to 15 minutes, building speed lap by lap, then letting them cool and rest for at least 24 hours, ideally a week.
• Watch the weatherDry and warm onlySemi-slicks are dry tires, and none of them are rain tires. They also hate the cold, and like any summer tire they can crack if stored below about −7°C.
• Think about a second setWheels or a trailerMost people keep track tires on their own wheels and swap at the track, so they’re not driving to work on a tire with three heat cycles left.
• Check the rulesRun group and insuranceTrack-day groups set their own tire rules, often by run group, and some insurers treat R-compounds differently. Ask before you book.

Track tire pressure: set it hot, not cold

On track, the number that matters is the hot pressure, measured within a minute or two of coming off track. Air in a hot tire typically rises 4 to 12 psi over a session. Performance Plus Tire suggests hot targets of about 33 to 39 psi for street performance tires, and Hoosier lists 32 to 42 psi hot for its DOT radials depending on car weight, from cold starting pressures as low as 26 psi.

1. 1. Start lowerFor street performance tires, start a few psi below the door sticker (never below the maker’s minimum) so you land on target hot.
2. 2. Check hot, right awaySame gauge, same routine, straight after the session, before the tires cool.
3. 3. Bleed to the hot targetOnly ever let air out down to your hot number. Bleeding to the cold number leaves you badly underinflated once they cool.
4. 4. Reset for the drive homeBack to the door-sticker pressure, cold, before you get on the highway.

06 · Tire pressure

What Tire Pressure Should You Run?

Use the pressure on the sticker in your driver’s door jamb (sometimes inside the fuel door or glove box). That’s what your car’s maker tested it with, and it’s usually somewhere around 220 to 240 kPa, or 32 to 35 psi, for a typical car. Front and rear numbers can differ. Summer and winter tires in the same size run the same pressure unless the tire maker says otherwise. (Track days are different; see the track pressure tips above.)

Two things people get wrong: running the “Max. press.” number from the sidewall (too high, which shrinks the contact patch and hurts grip), and letting air out for “more traction” in snow. Underinflated tires handle badly, wear out faster, use more fuel and can overheat. Don’t do it on the road.

A good gauge costs a few dollars. Most read in psi; door stickers in Canada usually show kPa too.

Why your tire light comes on the first cold morning

Air shrinks as it cools. According to Goodyear, tire pressure drops roughly 1 to 2 psi for every 5.6°C (10°F) the temperature falls. Set your tires in a 20°C garage, drive out into −10°C, and you can be 5 psi or more low without any leak at all. That’s why the tire pressure warning light so often comes on during the first cold snap of the year.

1. 1. Check coldCheck before driving, or after the car has sat for a few hours. A warm tire reads high.
2. 2. Check outside temperatureIf you fill up in a heated garage, the pressure will drop when you drive out into the cold. Check it once the car has cooled to outside temperature.
3. 3. Check monthlyAnd after every big temperature swing. Only 30% of Canadian drivers checked monthly in a Rubber Association of Canada survey.
4. 4. Don’t wait for the lightThe warning only has to come on once a tire is 25% low under US rules. On a 33 psi tire, that’s already about 8 psi down.

Swapping to winter tires on their own wheels? Make sure the new wheels have working pressure sensors, or the warning light will stay on all winter. Most shops can fit and program sensors when you buy the set.