When should you switch to summer or winter tires?

Many drivers use one of two rules of thumb when planning a tire change: the “zero to zero rule” or the 7-degree limit.

The “O-to-O rule” states that winter tires are only used from October until Easter. The 7 degree limit is based on the outside temperature and the assumption that summer tires have the best grip at temperatures above 7 degrees.

“Both rules of thumb have their flaws and are only partly true,” explains Ahmed Leser, vehicle expert at TÜV Thüringen. In general, snowfall in our latitudes is possible from October to April. If Easter falls at the end of March or the first week of April, the road conditions thereafter can be very wintry.

Readers also have objections to the 7-degree limit: while it is correct in principle that summer tires have better grip than winter tires at this temperature, the assumption can only serve as a rough guide: “Who knows for sure if warmer a period in March followed by a colder period with snowfalls in April?” Readers are concerned.

Therefore, the expert advises: “When it comes to changing tires, drivers should keep an eye on the long-term weather trend. Specific dates, such as Easter or certain temperatures, can only give a rough idea.”

Should I switch to summer or winter tires at all?

In Germany, there is a situational obligation to use winter tires, according to Auto Club Europa (ACE). It is not tied to a specific date, but indicates that the tires must be adapted to the respective weather situation. Therefore, winter tires are mandatory when driving on ice, snow, slush, ice or frost.

Road Safety Topic: What should I consider when choosing tires before changing them?

Tires wear out over time, so they should be checked regularly for damage. The tread depth should also be checked regularly. According to the rules of the road, this must be at least 1.6 millimeters, otherwise the tire will no longer be considered serviceable and a fine is due.

The tread depth of 1.6 mm applies to summer and winter tires in Germany. However, since this is what determines traction in the first place, car clubs recommend a minimum tread depth of 4mm for winter tires as well.

In addition, drivers should also pay attention to the age of winter tires, according to ADAC. After six years, the rubber compound on them becomes so hard that traction is reduced at low temperatures. Tire age can be recognized by the so-called DOT number, which is a four-digit number on the tire wall that begins with the letter combination “DOT”. The four digits indicate the calendar week and year of manufacture.

There are also all-season tires. Wouldn’t that save me the trouble of changing tires?

According to ADAC, all-season tires are legally considered winter tires. However, to do so, they must meet the following criteria:

• Modern winter tires have an alpine symbol, which is a mountain pictogram with a snowflake.
• In addition, until September 30, 2024 tires marked “M+S” are considered suitable for winter use if they were manufactured before December 31, 2017 (DOT number 5217).

If none of the markings is present, the tire is not an all-season tire, but a summer tire with all relevant ice and snow restrictions.

Can’t I just “use” my old winter tires in the summer?

The use of winter tires in summer is not expressly prohibited. And by law, tires are usually required to have a minimum profile of 1.6 millimeters, according to ADAC.

However, winter tires with a tread depth of less than 4 millimeters should not be “used”: in summer temperatures, winter tires show weaknesses that can even be dangerous to you and others. Among other things, dry braking and traction are dangerously degraded at high asphalt temperatures.

Do I need to go to the workshop to change the wheel?

No, drivers can also change tires themselves. All you need for this is suitable wrenches, a jack, a torque wrench and, if necessary, a rust remover spray. Then do the following:

• To fix the car, apply the handbrake. On vehicles with automatic transmission, move the selector lever to the park position “P”.
• Now loosen the hubcaps or wheel covers with the appropriate tool.
• Then loosen the wheel bolts about a quarter of a turn with a wrench. Always loosen wheel bolts before jacking up. If the screws are rusty, use a rust remover spray.
• Use the jack to raise the car. Attention: Each vehicle has its own jacking point. Check your vehicle’s owner’s manual to find out exactly where it is. Also make sure the jack is securely supported when lifting. Otherwise, lower the vehicle first and then jack it up again.
• Now completely unscrew the wheel bolts.
• Now you can remove the wheel. The car must be jacked up so that the wheel hangs a little in the air.
• Clearly mark the wheels you removed so you know where to put them next spring or fall. For example, use chalk to write “HL” for “rear left” on the corresponding wheel.
• Now fit the new wheels to the car according to their markings, insert the screws and lightly tighten them – always crosswise – out of order.
• Lower the vehicle with the jack only until the wheel touches the ground.
• Now use a torque wrench and tighten the screws crosswise until the torque wrench engages. The correct torque can be found in your vehicle’s log book.
• Now lower the car completely and remove the jack.
• Check the air pressure and inflate the tire as instructed in the owner’s manual. You can also drive to the nearest gas station to check the air pressure after a complete tire change.
• After a run of 50 to 100 km, the tightness of the wheel nuts should be checked again with a torque wrench and, if necessary, tightened.

Used sources:

• Material of the German Press Agency (dpa)
• ace.de mandatory winter tires
• adac.de: Changing tires or rims yourself: information, instructions, tips
• adac.de: Tires: Proper tread depth for better grip
• adac.de: Winter tires are a must: safe driving on snow and ice

Note: This article is from our archives.