Every driver has noticed at least once that the car's steering wheel began to behave differently than when buying the car. Sometimes, to change the trajectory of movement, you have to turn the steering wheel to a larger angle, and sometimes the steering wheel seems to have free play, which does not lead to an immediate reaction of the wheels. It is this phenomenon that in technical documentation and traffic regulations is called total backlash.
Understanding the nature of this parameter is critical not only for passing a technical inspection, but also for ensuring your own safety on the road. Total backlash - this is the total angle of rotation of the steering wheel from the extreme left position, at which the steering wheels begin to turn to the right, to the extreme right position, at which the wheels begin to turn to the left. Simply put, this is that backlash that does not lead to a change in the direction of movement of the car.
Ignoring this parameter can lead to serious consequences, including loss of control at high speed. In this article we will examine in detail the standards, testing methods and consequences of operating a vehicle with faulty steering.
Total backlash standards according to the Russian Federation Traffic Regulations
The legislation of the Russian Federation clearly regulates the maximum permissible values of free play of the steering wheel. These standards are stated in the “Basic provisions for the approval of vehicles for operation” and are mandatory for all categories of drivers. Exceeding these values is equivalent to a malfunction that prohibits the operation of the vehicle.
For passenger cars based on trucks, buses and trolleybuses, the following limit values apply:
- 🚗 Passenger cars - no more than 10 degrees.
- 🚛 Trucks - no more than 25 degrees.
- 🚌 Buses - no more than 20 degrees.
It is worth noting that for passenger cars the norm of 10 degrees is the most stringent. This is due to the high speeds at which such vehicles operate and the need for an instant driver response to changing road conditions. Excess of play even a couple of degrees can significantly increase the vehicle's braking distance.
The physical essence of play in the steering mechanism
To understand where free play comes from, it is necessary to consider the steering design. Backlash does not occur at one point, but is the sum of the gaps in all joints: from the steering wheel to the steering knuckles. In modern cars with power steering (hydraulic or electric), the situation can be more complex due to the presence of additional elements.
The main places where gaps form are:
- ⚙️ Splined connection of the steering column shaft.
- ⚙️ Gear transmission in the steering mechanism (rack or worm).
- ⚙️ Tie rod joints and ends.
It is important to distinguish between structural play, which is designed by engineers to compensate for thermal expansion and lubrication, and operational play, which occurs due to wear. Power steering (Power steering) can also make its own adjustments if there are air pockets in the system or wear on the pump, although this affects the force rather than the geometric play. However, if steering rack has wear in the teeth, this will directly increase the free play.
⚠️ Attention: Even if the total play is within the normal range, but you feel jerking or jamming when turning the steering wheel, operating the car is prohibited. Smooth operation is more important than degrees of free movement.
Methods for measuring steering free play
Checking the total play can be done either in specialized service centers or independently with a minimum set of tools. The official methodology, prescribed in GOST 22246-96, requires the use of a special device - a play meter, which is installed on the steering wheel.
However, for initial diagnostics in a garage, you can use a regular protractor or even a ruler if you know the conversion technique. The measurement is carried out on a horizontal platform with a dry and clean surface. The engine must be running (for the power steering to work) and the wheels must be straight.
The measurement process is as follows:
- Fix the zero mark on the stationary part of the steering column.
- Turn the steering wheel in one direction until the wheels begin to move (an assistant can determine this or you can monitor the tire projector).
- Lock the rotation angle.
- Repeat the procedure on the other side.
- The sum of the rotation angles before the wheels begin to move is the desired backlash.
When using a ruler, measure the movement of the steering wheel rim. For a standard 400mm handlebar, 17mm of rim offset roughly equates to 1 degree of rotation. Thus, for a passenger car, the maximum rim displacement should not exceed 170 mm (total in both directions from the center before the wheels begin to move).
☑️ Steering diagnostics
The influence of tire condition and pressure on play
Many drivers forget that the feeling of a “wobbly” steering wheel and increased free play can be influenced not only by mechanical components, but also by the condition of the wheels. Low tire pressure or severe tread wear creates the illusion of increased play because the tire sidewall deforms before the rim begins to turn.
This is especially true for cars with wide profile tires. The soft sidewall acts as an additional spring, smoothing out the first degrees of steering rotation. Therefore, before you climb under the car and adjust steering rack, make sure the tire pressure meets the manufacturer's recommendations.
It is also worth considering the type of tire. Winter tires are usually softer than summer tires, and their sidewall can introduce an error of up to 1-2 degrees in measurements. This is not a malfunction, but may cause a formal failure to pass a strict technical inspection.
Table of acceptable values and consequences
For clarity, we present a summary table that will help you quickly navigate the regulations and possible risks.
| Vehicle type | Maximum backlash (degrees) | Risk if exceeded | Action of the traffic police |
|---|---|---|---|
| Passenger cars | 10° | High risk of skidding at speed | Prohibition of operation |
| Trucks | 25° | Increasing turning radius | Prohibition of operation |
| Buses | 20° | Course instability in the wind | Prohibition of operation |
| Motorcycles | 15° | Loss of balance | Prohibition of operation |
As can be seen from the table, the requirements for passenger cars are the most stringent. This is due to the fact that at high speeds, even a minimal delay in the reaction of the wheels can lead to an accident. Exceeding the norm of 10 degrees for a passenger car means that at a speed of 90 km/h the car will travel straight ahead for several meters by inertia, despite the driver’s active steering actions.
Why are the standards for trucks higher?
The standards for trucks and buses are higher (20-25 degrees) due to the design features of their steering mechanisms. Trucks often have longer tie rods, more articulation joints, and mechanical gearboxes with higher ratios. In addition, the weight of the vehicle requires more force, and engineers provide large clearances to prevent the mechanism from snagging under load. However, this does not mean that you can drive a truck with a loose steering wheel - this is dangerous due to the long wheelbase and the risk of trailer folding.
Reasons for increasing backlash and fault diagnosis
If the measurements show exceeding the permissible values, it is necessary to find the source of the problem. The most common culprit is worn tie rod joints. They develop a finger seat, which leads to looseness. The second most popular reason is wear of the gear pair in the rack or gearbox itself.
It is also worth paying attention to the following nodes:
- 🔍 Steering shaft driveshaft (often rusts and wedges or breaks).
- 🔍 Steering column shaft bearings.
- 🔍 Pendulum lever (in classic pendants).
For accurate diagnosis, the car is raised on a lift. The assistant should sharply rotate the steering wheel left and right, and at this time you feel all the connections with your hand. The play will be tactilely felt as a blow or displacement of parts relative to each other. Pay special attention to the places where the steering rack is attached to the subframe - loose fastening bolts can give the effect of play in the entire system.
When diagnosing, use a mounting blade. Try using it to pry the steering rod up and down. If you feel free play in the tip joint, it must be replaced, even if the boot is intact.
Legal consequences and penalties
Operating a vehicle with faulty steering is considered a serious violation. According to Article 12.5 Part 1 of the Code of Administrative Offenses of the Russian Federation, driving a vehicle with faults for which operation is prohibited entails a warning or the imposition of an administrative fine in the amount of 500 rubles.
However, the amount of the fine is not the biggest problem. The main danger lies in the fact that if such a malfunction is detected, the traffic police inspector has every right to prohibit further movement of the vehicle. This means you will have to call a tow truck at your own expense or make repairs on site if possible.
In addition, in the event of an accident, even if you are not at fault for other reasons, the presence of faulty steering (excessive play) may become the basis for reconsidering guilt or admitting mutual guilt. The insurance company can also use this fact to refuse payment, arguing that the car is technically faulty.
⚠️ Attention: If the inspection reveals a backlash that exceeds the norm, you will be given a diagnostic card marked “Failed”. Without a valid diagnostic card, it is impossible to issue an MTPL policy, and driving without MTPL entails additional fines.
Adjustment and Troubleshooting
Elimination of the total backlash depends on its cause. If the tips or rods are worn out, only replacement helps. There is nothing to regulate there, since the metal is already worn off. If the problem is in the steering rack, it is often possible to adjust the clamping mechanism.
Many modern racks have an adjusting screw with a lock nut. By tightening it, you can select the gap between the gear and the rack.
Procedure:1. Loosen the locknut.
2. Tighten the adjusting screw until the play disappears (without fanaticism!).
3. Check the ease of rotation of the steering wheel (it should not bite in extreme positions).
4. Tighten the locknut while holding the adjusting screw.
It is important not to overtighten the mechanism. If you clamp the rack too tightly, it will begin to wear out quickly, and the steering force will become enormous, which is also a violation of the rules (steering force standards also exist). After adjustment, be sure to check the total play again.
Proper adjustment of the steering rack allows you to extend the life of the unit and remove play without expensive replacement, but it requires precision and understanding of the design.
Does wheel alignment affect the total play?
Wheel alignment itself does not affect the degrees of free play of the steering wheel. However, if the wheel alignment angles are incorrect, the car may pull to the side, and the driver has to constantly steer to maintain the trajectory. This creates a subjective feeling of instability, which is confused with play. In addition, if the toe-in is severely misaligned, uneven tire wear may occur, which, as we found out earlier, affects the sharpness of the steering response.
Is it possible to drive with a backlash of up to 15 degrees in a passenger car?
Absolutely not. The limit for passenger cars is 10 degrees. A backlash of 15 degrees is an increase in the norm by 50%. At a speed of 60 km/h this may still be tolerable, but if you urgently avoid an obstacle on the highway (100+ km/h), the car will not have time to react to your actions, and you may fly into the oncoming lane or onto the side of the road. This is a direct threat to life.
Why did the play not disappear after replacing the steering tips?
If replacing the tips does not help, the source of the play is deeper. This could be the steering rack itself (wear of the teeth or sliding bushings), the steering shaft driveshaft, or even worn out silent blocks of the suspension arms. In some cases, play is caused by a broken wheel hub bearing, which allows the disk to “walk” a little relative to the axis.
How often should steering play be checked?
Officially - at every scheduled technical inspection (once every year or two). However, it is recommended to carry out a quick check yourself every 10-15 thousand kilometers or after getting into deep holes. A sharp impact of the wheel on an obstacle can instantly disable the tip or bend the rod, creating a dangerous backlash.