Systematic Study to Understand and Resolve Brake Pull in Commercial Vehicles Using Simulation and Proving Ground Tests

2026-26-0083

1/16/2026

Authors
Abstract
Content
In traditional commercial vehicles with leaf spring suspension and Recirculating Ball Joint (RCBT) steering systems often experience undesirable pulling due to unsymmetrical steering mechanism during braking, especially when the suspension and steering hardpoints are not properly tuned. This work analyzes the mechanisms responsible for pulling tendencies, primarily addressing brake steer and bump steer, which occur due to misalignments in the suspension and steering geometries. Brake steer occurs when braking forces create an imbalance in torque, resulting in the vehicle deviating to one side. On the other hand, bump steer refers to the unwanted changes in the wheel alignment when the suspension undergoes travel, leading to instability or unintended steering input. These two phenomena, if not controlled, can result in undesirable vehicle handling, especially under heavy braking conditions. This work focuses on evaluating these mechanisms and suggests strategies for minimizing their impact through accurate suspension and steering hardpoint tuning. A dedicated methodology was formulated to optimize suspension and steering hardpoints, leveraging Adams Car MBD simulations for fast and accurate predictions of pull direction. Adjustments were made to the front leaf spring pivot and Pitman arm draglink pivot to address bump steer, and the knuckle-to-draglink joint was optimized to minimize brake steer. Simulation outcomes showed that the severe right pull initially observed was reduced to a mild left pull after these changes. Despite offering valuable tuning strategies and directional predictions, the study acknowledges that exact pull magnitude cannot be predicted with certainty due to complex vehicle dynamics. However, the study successfully establishes a method for predicting pull direction, which can serve as a strong foundation for further refining suspension and steering system designs in small commercial vehicles.
Meta TagsDetails
Pages
4
Citation
Pandhare, V., M, A., Nizampatnam, B., Londhe, A., et al., "Systematic Study to Understand and Resolve Brake Pull in Commercial Vehicles Using Simulation and Proving Ground Tests," SAE Technical Paper 2026-26-0083, 2026, https://doi.org/10.4271/2026-26-0083.
Additional Details
Publisher
Published
Jan 16
Product Code
2026-26-0083
Content Type
Technical Paper
Language
English