2022-2024 BMW Steering Clunking and Jerking at Low Speeds

BMW has released Service Information Bulletin (SIB) SI B36 01 21, dated January 8, 2024, to address customer inquiries regarding "clunking sounds" and a "jerking" sensation experienced in various 2022-2024 BMW models. This bulletin, which supersedes a previous version, SI B36 01 21 dated April 2021, clarifies the nature of these symptoms, particularly when driving at low speeds with a large steering angle.

This bulletin applies to a wide range of BMW models from 2022 to 2024, including various 2 Series, 3 Series, 4 Series, 5 Series, 7 Series, 8 Series, X3, X4, X5, X6, X7, XM, and i8 vehicles, specifically when they are equipped with Summer/High Performance (HP) tires.

Symptoms

Owners may notice a distinct BMW steering clunking jerking sensation from the front end of their vehicle. This typically occurs at low outside temperatures, specifically below 40 degrees Fahrenheit, and during slow driving speeds. Situations like parking or maneuvering with a large steering angle are common triggers.

The front end of the vehicle might feel slightly axially misaligned, leading to a "jerking" sensation or an audible "clunk". This acoustic acknowledgement of the clunking can be observed in specific conditions, as referenced in BMW's internal video V36 01 21.

Cause of the Issue

The technical explanation for the BMW steering clunking jerking behavior lies in the vehicle's front axle geometry, which is deliberately designed to deviate from the standard "Ackermann function". The Ackermann function ensures that the inside wheel turns at a greater angle than the outside wheel, allowing for a tighter turning radius and preventing the inside tire from scrubbing on the pavement.

This design, originally patented in 1818 for horse-drawn carriages, becomes evident in improved handling and a reduced vehicle turning radius. However, when combined with Summer/High Performance (HP) tires, especially those with enhanced grip levels, the issue arises. These tires exhibit reduced profile elasticity at low temperatures due to their specific rubber compound and profile design.

This reduced elasticity causes tension in the tire when driving slowly with very large steering angles. When rolling, particularly during abrupt changes in the coefficient of friction (e.g., due to varying road surfaces), this tension is released in individual or successive "jerking" movements. This phenomenon is further illustrated in video V36 02 21.

Important Warnings for Owners

BMW explicitly states that this "jerking" behavior is a normal characteristic of agile/sporty vehicles under these conditions and is not a defect. Owners should be aware of the following:

• There is no vehicle damage involved.
• This is of no consequence for vehicle safety.
• This does not cause tension in the all-wheel drive drivetrain.

Diagnosis and Recommendations

For technicians, the bulletin outlines diagnostic steps to confirm that the "jerking" and "clunking" are indeed due to the "Ackermann function" and not another issue. These steps include:

1. Repeating the driving condition using warmed-up tires, which can be achieved by driving the vehicle or parking it in a climate-controlled garage or workshop.
2. Repeating the driving condition with a tire that has a lower grip level, such as winter tires or all-season tires.
3. Checking wheel alignment and making any necessary corrections if there's any indication of damage, such as "curb rash", then reassessing the situation.

BMW recommends that customers use winter or all-season tires during the cold season if the diagnostic steps confirm the "jerking" or "clunking" is due to the "Ackermann function". This can help mitigate the sensation by providing tires with better elasticity in cold temperatures.

Claim Information

This Service Information Bulletin provides technical information to aid in understanding the situation. For technical inquiries, feedback can be submitted via the bulletin. Warranty inquiries should be directed to the Warranty department through Live Chat on the Warranty Documentation Portal or IDS by selecting Coverage, Policy, Coding Questions, and Mileage Corrections.

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Source: NHTSA ID: 10249767