What Causes Vehicle Pulling to One Side?
2 Answers
The reasons for a vehicle pulling to one side include the following: 1. Uneven tire pressure on both sides: Normally, a car's tire pressure should be between 2.0~2.5MPa (refer to the vehicle's user manual for exact specifications). Higher tire pressure causes the tire to expand more, increasing its diameter. Consequently, the tire covers a longer distance per rotation (due to a larger circumference). In this scenario, the tire with higher pressure travels a longer distance, while the tire with lower pressure covers a shorter distance. Additionally, higher tire pressure reduces the contact area with the ground, decreasing rolling resistance. As a result, the vehicle tends to pull toward the side with lower tire pressure. 2. Uneven tread wear on both sides: The surface of a tire has rubber treads with a certain thickness, which diminishes over time with use. This situation is somewhat similar to the first case. A tire with more tread wear effectively has a smaller diameter, causing the vehicle to pull toward the side with more tread wear when driving. 3. Poor piston retraction in one side's brake caliper: If the brake piston on one wheel does not retract properly, it increases the rolling resistance on that side. Even without applying the brakes, the vehicle will pull toward the side with higher resistance. 4. Inconsistent wheel hub bearing preload on both sides: During wheel hub bearing installation, the nut outside the bearing is tightened to apply a certain preload. A higher preload increases the wheel's rotational resistance. If the preload on the tapered bearings differs between the left and right sides, one wheel will have higher rotational resistance, causing the vehicle to pull toward that side.
I've been driving for half my life and have encountered steering pull issues many times. The most common cause is uneven tire pressure—when the pressure difference is significant, the steering wheel naturally pulls toward the side with lower pressure. Another factor is uneven tire wear. Once, my car pulled severely on the highway, and when I got home, I found the right front tire was completely worn out while the left side was still like new. Wheel misalignment is also a frequent issue—incorrect toe angles or weakened suspension springs can cause the car to drift. Also worth mentioning is brake system failure; if one side's brakes drag or malfunction, the car will pull in that direction. Safety is no trivial matter. Every time this happens, I immediately check the tire pressure. If that's fine, I head straight to a professional shop for an alignment check. Don't wait for a small issue to become a major hazard—delaying only costs you more in the long run.
