Profile depth measurement

The tread depth measurement in vehicle tires is the measurement of the depth of the grooves, so the distance from the tread plane of the bottom of the tread grooves or -einschnitte. As a rule, the depth of the wide grooves and incisions on the tread (without the tire shoulders) that serve to drain water is decisive. Most countries have a legally regulated minimum tread depth for pneumatic tires for motor vehicles . In Europe, the minimum tread depth of 1.6 mm applies to summer tires for cars . Sometimes there are special requirements, for example for different types of vehicle. With winter tires, the minimum tread depth varies greatly depending on the country. Since the actual tread depth of a tire decreases due to progressive wear of the tread, the remaining tread depth is measured in order to draw conclusions about changes in driving characteristics and road safety.

Legal basis for the profile depth

In Germany the Road Traffic Licensing Regulations (StVZO) apply , in Austria the Motor Vehicle Act and the Motor Vehicle Act Implementation Ordinance (see section Regulations in the article Car tires ), in Switzerland the ordinances VTS , TAFV 1, TAFV 2, TAFV 3.

Road Traffic Licensing Regulations

Section 36 StVZO contains the provisions for tires and treads of motor vehicles and trailers. Section 36 of the StVZO does not apply to the different types of treads of road rollers, snow plows and sledges, but their treads must also protect solid roadways as much as possible (Section 30 of the StVZO).

Section 36 (3) of the StVZO contains the following regulation: The wheels of motor vehicles and trailers must be fitted with pneumatic tires, unless other tires are permitted below. Pneumatic tires are tires whose working capacity is mainly determined by the excess pressure of the enclosed air. Pneumatic tires on motor vehicles and trailers must have tread grooves or incisions around the entire circumference and across the entire width of the tread. The main profile must have a profile depth of at least 1.6 mm over the entire circumference; The main profile is the wide profile grooves in the middle area of the tread, which takes up about 3/4 of the tread width.

According to this, the tread depth in the middle area (main tread) of the tread of each running tire must be at least 1.6 mm all around, even with winter tires (Section 36 Paragraph 3 Sentence 4 StVZO). An exception applies to bicycles with an auxiliary motor, small motorcycles and light motorcycles, here a profile depth of at least 1.0 mm is required.

Directive 89/459 / EEC

Thus, the StVZO corresponds to Directive 89/459 / EEC of July 18, 1989 on the tread depth of tires, which provides for a minimum tread depth of 1.6 mm for tires. Since the minimum tread depth has proven to be too strict for some speed-limited motorcycles, a tread depth of 1.0 mm is sufficient for bicycles with an auxiliary motor, small motorcycles and light motorcycles (see Section 36 (2) sentence 5 StVZO). Additional fine profiles are not taken into account, which is now expressly derived from the wording (“the wide profile grooves”) of Section 36 (2) sentence StVZO. “Average lows” are irrelevant; Also out of consideration are grooves that are used exclusively for purposes other than slip resistance and water absorption.

Tire wear indicator

The tread depth is measured in the main grooves, which on modern tires are marked with a tire wear indicator. If these additional crossbeams are flush with the surrounding profile, there is between 0.8 and 1 mm of residual profile, depending on the manufacturer. The marking does not correspond to the required profile depth of 1.6 mm.

Manual measuring devices

One euro coin

One euro coin test

The cheapest option: If the brass edge of the coin disappears completely in the profile, the minimum profile depth applicable in many countries is still available. If it is level with the profile, the profile is still about 3 millimeters deep.

Purely mechanical profile depth gauge

Analog profile depth gauge

The mechanical profile depth gauge is based on the simple principle of the depth measuring device of a caliper . Handling is as easy as using a ruler. The value is read from the scale applied. The profile depth gauge is placed between two profile blocks and the measuring rod is pushed down to the bottom of the profile. You only have to make sure that there are no objects in the profile and that no measurements are taken at a point where a TWI (Tread Wear Indicator) is located.

Digital tread depth gauge

The only difference to the purely mechanical profile depth gauge is the display. The digitally displayed value only has to be read off.

Digital tread depth gauge
Digital tread depth gauge

Automatic measuring devices

Laser triangulation

Automatic tire measurement when driving over the measuring device

Detailed view of an automatic tire measurement

Using laser triangulation , it is possible to measure the tread depth and profile over the entire width of the tire. The measurement is carried out when driving over the measuring device installed flush with the surface of the vehicle up to vehicle speeds of over 100 km / h. The imaging process not only enables the minimum tread depth to be determined, but also makes it easier to recognize unevenly worn tires and to draw conclusions about incorrect track and camber settings.

Since the effort for such a system is considerable, it is mainly used where many measurements are to be carried out efficiently (traffic monitoring, car dealerships, vehicle fleets, etc.). The measurement is only carried out on a short area of the tire circumference. It is therefore not a substitute for manual checks and cannot detect whether there are defects in other parts of the tire.

Recommended minimum tread depth

Since a decreasing tread depth increases the risk of aquaplaning, many experts advise increasing the minimum tread depth. The Tire Safety Initiative, an initiative of the German Road Safety Council Association, provides advice on tire care.

Country-specific minimum profile depth

The known and legally verifiable figures for the minimum profile depth should be listed here. In some cases, special requirements apply that are not specified here, for example for different vehicles such as mopeds, trucks or buses. The categories mentioned in the table can be roughly described as car tires / passenger cars for car tires , commercial / truck for commercial tires, motorcycle tires for motorcycle and bus for bus tires .

country	category	summer	winter	Remarks
Germany	Car Tires	1.6 mm	1.6 mm	In black ice, slippery snow, slush, frost or slippery ice, you may only drive with winter tires (M + S tires).
	Commercial Tires	1.6 mm	1.6 mm	In black ice, slippery snow, slush, frost or slippery ice, you may only drive with winter tires (M + S tires). Exceptions: agricultural and forestry vehicles, certain emergency vehicles, non-driven wheels of vehicles of classes M2, M3, N2, N3 , (heavy trucks, buses).
	Moped tires	1.0 mm	1.0 mm	Only applies to bicycles with an auxiliary motor, small motorbikes and light motorcycles (Section 36 (2) sentence 4 StVZO)
Denmark	Car Tires	1.6 mm	1.6 mm	no compulsory winter tires
	Commercial Tires	1.0 mm	1.0 mm	no compulsory winter tires
	Motorcycle	1.0 mm	1.0 mm	no compulsory winter tires
Estonia		1.6 mm	1.6 mm	Winter tires are compulsory from December 1st to April 1st - but may vary!
Finland	Car Tires	1.6 mm	3.0 mm	Winter tires are compulsory from December 1st to March 1st
	Commercial Tires	1.6 mm	k. A.	Winter tires are compulsory from December 1st to March 1st
	Motorcycles	1.0 mm	k. A.	Winter tires are compulsory from December 1st to March 1st
France	Car Tires	1.6 mm	1.6 mm	no general winter tire requirement. Winter tires are mandatory on some mountain roads!
France	Commercial Tires	1.6 mm	1.6 mm	no general winter tire requirement. Winter tires are mandatory on some mountain roads!
Great Britain	Car tires	1.6 mm	1.6 mm	no compulsory winter tires
	Commercial and bus tires	1.0 mm	1.0 mm	no compulsory winter tires
	Motorcycle	1.0 mm	1.0 mm	no compulsory winter tires
Italy	Car Tires	1.6 mm	1.6 mm	no compulsory winter tires
	Commercial Tires	1.6 mm	1.6 mm	no compulsory winter tires
	Motorcycle	1.0 mm	1.0 mm	no compulsory winter tires
Latvia		1.6 mm	1.6 mm	Winter tires are compulsory from December 1st to February 29th
Lithuania		1.6 mm	3.0 mm	Winter tires are compulsory from November 10th to April 1st
Luxembourg		1.6 mm	1.6 mm	Winter tires are compulsory for all cars in winter road conditions, d. H. "Black ice, frozen snow, melting snow, ice sheets or roads with frost" This also affects foreign vehicles, i. H. the rule applies to everyone who drives in Luxembourg, and not just to drivers who have a Luxembourg license plate
Norway	Car Tires	1.6 mm	3.0 mm	Tires with sufficient grip
	Commercial Tires	1.0 mm	1.0 mm	Tires with sufficient grip
	Motorcycle	1.0 mm	1.0 mm	Tires with sufficient grip
Austria	Car Tires	1.6 mm	4.0 mm (5.0 mm for diagonal tires)	Winter tires are compulsory in winter driving conditions for cars from November 1st to April 15th (see also the section Austria in the article Car tires )
Austria	Commercial Tires (vehicles over 3500 kg)	2.0 mm	5.0 mm (6.0 mm for cross-ply tires)	Winter tires are compulsory in all driving conditions (even on dry roads) for trucks from November 1st to April 15th, for buses from November 1st to March 15th (see also the section Austria in the article car tires )
Sweden	Car Tires	1.6 mm	3.0 mm	Winter tires compulsory in winter conditions from December 1st to March 1st Tourists are exempt from the regulation - however, the remaining profile must be at least 3.0 mm
Switzerland	Car Tires	1.6 mm	1.6 mm	no general winter tire requirement
Slovenia		1.6 mm	3.0 mm	Winter tires are compulsory from November 15th to March 15th
Spain		1.6 mm	1.6 mm	no compulsory winter tires
Czech Republic		1.6 mm	4.0 mm	Winter tires are compulsory from November 1st to April 30th for vehicles up to 3.5 t GVW on certain roads (including motorway sections, mountain roads; according to signs) All four wheels must be equipped with winter tires (min. 4 mm tread depth); Vehicles over 3.5 t GVW must have winter tires with min. 6 mm profile depth
Turkey		1.6 mm	1.6 mm	no general winter tire requirement Use of winter tires can be ordered by traffic sign
Ukraine		1.6 mm	6.0 mm	Winter tires are compulsory in winter road conditions (approx. November to April)
Hungary		1.6 mm	1.6 mm	no general winter tire requirement Use of winter tires can be ordered by traffic sign

swell

↑ Ordinance on the technical requirements for road vehicles (VTS)

↑ Committee of European Tire Retail Organizations ( Memento of the original from July 11, 2012 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 165 kB) @1@ 2

↑ Ordinance amending the Road Traffic Act and the Ordinance on the Catalog of Fines of December 1, 2010 ( Federal Law Gazette I p. 1737 )

↑ Minimum tread depth in Europe. Retrieved September 12, 2017 .

↑ "Light and Tires" 2015 campaign. Accessed on August 16, 2016 .

↑ Tageblatt, Luxembourg: The ACL | requires 4 millimeters instead of 1.6 Day sheet. (No longer available online.) Archived from the original on August 16, 2016 ; accessed on August 16, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.

^ Republic of Austria: Minimum tread depth of tires. Retrieved September 12, 2017 .

Web links

[1] Ordinance on the technical requirements for road vehicles (VTS)