31.7. Is it permitted to install tyres with different tread patterns on the same axle of a passenger car?
UAЧи дозволяється встановлювати на одну вісь легкового автомобіля шини з різним малюнком протектора?
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This exam question from the Traffic Rules of Ukraine checks a basic safety principle: the wheels on one axle must operate identically so that the car brakes predictably and maintains its trajectory. Different tread patterns on the left and right wheels alter road grip, water displacement, and behavior on slippery surfaces, which increases the risk of skidding and the car pulling to one side during maneuvering or emergency braking. That is why such requirements are directly related to road safety and often appear on the theoretical exam.
In content, this question belongs to the section of the traffic rules regarding the technical condition and operation of vehicles, specifically to point 31.4 and subpoint 31.4.5 (d) of the Traffic Rules of Ukraine (requirements for tires and wheels). The regulation directly classifies as a technical nonconformity the case when tires of different models with different tread patterns are installed on one axle of a passenger car, and operation with such nonconformity is prohibited.
When evaluating the answer options, statements about the possibility of fitting different treads on any axle or only on the rear axle do not comply with the requirements of 31.4.5 (d), since the prohibition applies specifically to one axle, regardless of whether it is the front or rear. In practice, this rule is simply explained: different treads on one axle provide different grip strengths and different braking responses, making the car less controllable; as an exception, in real life, a "spare/donut" is sometimes used only to reach a repair location, but such a combination is not suitable for regular use.
Clause 31.4
The operation of vehicles is prohibited under the law if the following technical malfunctions and non-compliance with such requirements are present.
(This is a general provision that establishes a ban on the operation of vehicles in case of non-compliance with technical requirements, in particular — requirements for tires.)
Clause 31.4.5 (d) (requirements for tires and wheels)
Diagonal tires together with radial ones, studded and non-studded, frost-resistant and non-frost-resistant, tires of different sizes or constructions, as well as tires of different models with different tread patterns for passenger cars, and different types of tread patterns for trucks, are installed on one axle of the vehicle.
(This subclause directly prohibits the use of tires of different models with different tread patterns on one axle of a passenger car, i.e., such tires cannot be installed for further operation.)
Therefore, the correct answer is "Not allowed," given that according to clause 31.4.5 (d) of the Traffic Rules, the operation of a passenger car is prohibited if tires of different models with different tread patterns are installed on one axle.
While driving, it is important that the wheels on the same axle operate identically: have the same grip on the road, channel water equally, and respond the same way to braking and turning. If the left and right wheels on one axle have different tread patterns, these properties differ, and as a result, the car may behave unpredictably.
The Traffic Rules of Ukraine directly classify such a situation as a technical non-compliance, which is prohibited for operation. Clause 31.4.5 (d) states that it is not allowed to install tires of different models with different tread patterns on the same axle of a passenger car. That is, even if both tires are of the same size and in good condition, but the tread is different, the Traffic Rules requirement is violated.
The practical meaning of this prohibition is simple: during braking on a wet or slippery road, one tire may "hold" better and the other worse, causing the car to pull to one side, increasing the risk of skidding or loss of stability. The same occurs in turns and during sharp maneuvers, when the difference in grip on one axle becomes critical.
Therefore, the correct answer is "Not allowed," since clause 31.4.5 (d) of the Traffic Rules prohibits the operation of a passenger car if tires of different models with different tread patterns are installed on the same axle, which impairs handling and safety.