Over the years, there’s been ongoing discussion on this forum around potential ABS/ESP issues* that can arise when changing wheel or tire sizes—particularly diameter or width—on rear-wheel-drive AMG GT models.
To help clarify the topic, here’s a concise summary of what you should know and how to properly re-calibrate the system of you wish to do so.

In most cases, a cumulative** diameter change of less than 5% (based on common limit stated in various forum posts) from the original (OEM) tire size is considered acceptable.
The ABS and ESP systems are generally capable of adapting automatically for most minor variations without intervention.
However, the wheel speed sensors themselves do not automatically re-calibrate, meaning your speedometer and odometer readings may become inaccurate.

If you’d like the speedometer to reflect the correct speed with the new tire diameter—or you’ve made changes exceeding that 5% threshold—it’s best to have the system re-calibrated so that both the ABS/ESP logic and speed sensors are synchronized with the new rolling circumference.

Fortunately, this is a straightforward procedure available at any Mercedes-Benz dealership. Simply request a “Diagnostic Recalibration” service to perform the following:

• Relearn Wheel Circumference
• Initialize Wheel Speed Sensors

The technician will connect your vehicle to the Mercedes-Benz STAR Diagnosis (Xentry) system, navigate to:

Control Units → Chassis → ESP/ABS → Adaptations

They will then execute the “Relearn Wheel Circumference” and/or “Initialize Wheel Speed Sensors” routines. Afterward, a short 10–15 minute drive is typically required to complete the learning process.
Once finished, the updated parameters are stored in the control unit memory—ensuring accurate wheel speed data, optimal ABS/ESP performance, and proper speedometer calibration.

This small but important step helps maintain the precision and balance Mercedes-AMG engineered into your GT, especially when operating near the limits of traction and performance.

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Technical Details:

* If the ABS (Anti-lock Braking System) and ESP (Electronic Stability Program) are not re-calibrated after changing wheel or tire diameters with excessive cumulative delta, several potential issues can arise.

Unstable or Premature ABS Activation: The ABS relies on precise data from all four wheel sensors to modulate brake pressure.

• With incorrect wheel circumference data, the ABS may pulse brakes unnecessarily.
• In emergency braking, it might extend stopping distance or cause a pulsing brake pedal under conditions where it shouldn’t activate.

ESP (Traction & Stability Control) Misbehavior: The ESP compares wheel speeds and yaw data to detect oversteer or understeer.

• If the system thinks one axle is rotating faster or slower than expected, it may apply braking force to the wrong wheel.
• This can cause unintended torque vectoring, reduced stability, or even cut engine power during normal acceleration.

** Cumulative diameter change is expressed as a percentage (%) and represents the relative difference between the OEM and new tire diameters. It is calculated separately for the front and rear tires as follows:

• Front Δ (delta) = (Front OEM Diameter ÷ New Front Diameter) − 1
• Rear Δ (delta) = (Rear OEM Diameter ÷ New Rear Diameter) − 1

The overall or cumulative delta (%) is then determined by subtracting the front delta from the rear delta:
Cumulative Δ = (Rear Δ) − (Front Δ)

 

This was informative and in my case good to know that i wont exceed that 5% threshold with a 285/345 setup.