Vehicle Dynamics Benefits of Polestar IPS Frictionless Braking SystemÂ
The Polestar IPS Frictionless Braking System (FBS) eliminates conventional friction brake components from the wheel ends, delivering a substantial reduction in unsprung and rotating mass at each corner.
This change improves road holding, chassis predictability and steering feel. For OEMs, the FBS is a chassis dynamics enabler as well as a braking technology.
1. Unsprung Mass and Its Impact
Unsprung mass comprises components between the suspension springs and the road: wheels, tyres, brake hardware, hubs, bearings and portions of the suspension links. Conventional brake assemblies contribute significantly to unsprung mass and also add rotating inertia.
Reducing unsprung mass improves tyre contact consistency, lowers dynamic tyre load variation and helps the suspension control wheel motion more effectively. Published studies show that decreasing unsprung mass reduces RMS tyre deflection, improving road holding.
2. How the FBS Changes Mass Properties
The FBS removes brake discs or drums, calipers, pads, shoes and associated hardware from each wheel end. This creates a large absolute reduction in unsprung mass per corner and lowers wheel rotational inertia.
Unlike incremental measures such as lightweight discs or calipers, the FBS represents a step-change in wheel-end mass reduction, shifting the sprung/unsprung mass ratio in favour of better dynamic control.
3. Vehicle Dynamics Benefits
Improved road holding. Lighter unsprung assemblies follow road contours more accurately, reducing wheel hop and momentary loss of contact. Dynamic tyre load variation is reduced, improving lateral and longitudinal force generation during cornering, braking and acceleration.
More predictable sprung mass behaviour. The suspension can absorb and dissipate road energy more effectively, reducing abrupt body motions and making vehicle response more linear and repeatable.
Enhanced steering sensitivity and feel. Lower wheel rotational inertia reduces gyroscopic resistance and steering effort, producing a lighter, more responsive steering feel and clearer feedback through the wheel.
4. Design and Development Implications
For OEM evaluators and chassis engineers, the FBS opens opportunities to retune spring and damper characteristics, bump/rebound control and roll stiffness distribution to exploit the improved wheel control.
The technology may also simplify NVH tuning by removing friction-brake noise sources and reducing certain high-frequency vibration modes associated with heavy wheel-end hardware.
Conclusion
The Polestar IPS Frictionless Braking System delivers a fundamental change in wheel-end mass properties by eliminating conventional friction brake components. The result is better road holding, more predictable chassis behaviour and lighter, more responsive steering.
For OEMs, this is not only a new braking paradigm but also an opportunity to improve overall vehicle dynamics without increasing total vehicle mass.