The car pulls to one side: finding the cause in three checks

“It pulls right” is the symptom people take straight to an alignment shop. Sometimes that is correct. But at least half the cases are solved more cheaply, and it can be checked on the road in ten minutes.

Three candidates

Tyres. Different pressures, different wear, mismatched models across an axle, or a defect in the tyre itself.

Brakes. A sticking caliper braking one wheel continuously.

Geometry. Alignment disturbed after a pothole or a repair.

Check one: pressures

The cheapest and most often decisive. A pressure difference across one axle produces noticeable pull.

Measure cold, with a gauge rather than by eye. A few tenths of a bar is already felt through the wheel.

Check two: swap the front wheels

The main test, and it separates the tyres from the car.

Swap the front wheels side to side. Then:

• The pull changed direction — a tyre is at fault. This is called conicity: an internal structural defect invisible from outside.
• The pull stayed the same — it is the car: brakes or geometry.

The test is free and settles half of all cases.

Check three: the hot disc

Drive a few miles without heavy braking and carefully bring a hand near each disc.

One disc noticeably hotter than the others means a sticking caliper. Supporting signs: a smell, a hum, the car rolling worse in neutral, higher fuel consumption.

When it is the geometry

The signs: the steering wheel sits off-centre on a straight road, tyres wear unevenly, and the symptom began after a pothole or suspension work.

What the electronics do with it: the steering angle sensor measures position against its own zero. After the geometry changes, the wheel sits crooked while the sensor treats that as straight ahead — hence stability codes and incorrect interventions; covered in the steering angle calibration article.

Important: an alignment without calibrating the sensor is half the job.

Two more causes

Suspension wear. A worn bush or ball joint changes geometry under load: straight on a level road, pulling under braking.

Road camber. Roads are cambered to shed water. A slight pull to the nearside in the left lane is normal, not a fault. Verify on an empty, level surface.

The procedure

1. Measure pressures on all four cold tyres.
2. Swap the front wheels and drive again.
3. Check disc temperature after a gentle drive.
4. Inspect the tread for uneven wear.
5. Read ABS and stability codes.
6. Alignment with steering angle calibration if the earlier checks are clean.

In short

• Swapping the front wheels is the main free test.
• If the pull changes sides, blame the tyre, not the car.
• A hot disc after a gentle drive means a caliper.
• A slight pull on a cambered road is normal.
• An alignment without sensor calibration is half the job.

Download the app — ABS, stability, and steering angle codes are read with an ELM327 adapter over Bluetooth SPP on Android.