Hitting a kerb can throw the suspension alignment out of kilter, even if the tyre and wheel rim appear undamaged, as the force of the impact is transferred to the steering links and the suspension components responsible for wheel alignment.
The effects of such an impact are not always immediately apparent — the car may handle seemingly normally for a while before the symptoms become obvious. After any significant impact with a kerb, we recommend having the wheel alignment checked at our workshop, rather than waiting until the car starts to pull noticeably to one side.
In short
- Hitting a kerb transfers force to the steering links and suspension components, altering the wheel alignment.
- The effects are not always immediately apparent — the car may handle seemingly normally for some time.
- A steering wheel that turns straight is not proof that the suspension is in good working order.
- After a harder impact with a kerb, it is worth having the wheel alignment checked, even if there is no visible damage.
Contents
1. What physically happens to the suspension when you hit a kerb?
2. Why can even a minor scrape throw the toe settings out of alignment?
3. What symptoms appear hours or days after the impact?
4. Does a steering wheel that turns straight away mean the suspension is fine?
6. What do we check after a kerb impact has been reported?
7. When should you go for an inspection straight away, and when can you wait?
What physically happens to the suspension when the car hits a kerb?
When hitting a kerb, the impact energy is transferred from the tyre and wheel rim to the suspension and steering components, such as tie-rods, link ends and control arms, which physically change their position or undergo slight deformation. As these components are responsible for precise wheel alignment, even a slight change in their geometry results in a change in the toe-in value without any visible mechanical damage. In extreme cases, following a high-speed impact, the wheel rim may also become bent or the tyre damaged, which further complicates the situation and makes it difficult to clearly identify the cause of the problem.
Why can even a minor scrape throw the toe-in out of alignment?
Even a seemingly minor scrape of the wheel against a kerb, at low speed and at an unfavourable angle, can transfer sufficient force to the end of the tie rod to slightly alter its alignment. Wheel toe is a value measured in fractions of a degree or millimetres, so a significant change does not require major damage; a slight shift in the adjustable component is sufficient. This is why drivers are sometimes surprised to learn that their wheel alignment has been thrown out of alignment following an incident which, in their view, was too minor to have caused any damage.
What symptoms appear hours or days after the impact?
The symptoms of misaligned wheel alignment following a kerb impact do not always appear immediately — sometimes the car drives seemingly normally for the first few dozen kilometres before the driver begins to notice a slight pull to one side. Over time, this symptom is accompanied by uneven tyre wear, which only becomes apparent after a few weeks of regular use. The delay between the incident and the appearance of clear symptoms means that many drivers do not link the deterioration in the car’s handling to a collision that occurred some time ago, but instead look for other causes.
Does a steering wheel that returns to centre mean that the suspension is in good condition?
A steering wheel that is straight whilst driving on a straight road is not proof that the suspension alignment remains intact, as a slight misalignment of the toe-in may not yet result in a noticeable pull to one side. It sometimes happens that the steering wheel remains straight, yet the wheels are rolling at a slightly incorrect angle, which only becomes apparent as uneven tyre wear over a longer period. Therefore, the mere absence of visible symptoms immediately after hitting a kerb should not be the sole criterion for deciding against having the wheel alignment checked.
How can you tell the difference between a wheel alignment issue and damage to a wheel rim or tyre?
Damage to a wheel rim caused by hitting a kerb usually manifests as a noticeable vibration in the steering wheel at a certain speed and, sometimes, an audible clunk when driving over uneven surfaces, whereas misaligned wheel alignment is primarily indicated by the car pulling to one side and uneven tyre wear. A damaged tyre, for example one with a bulge on the sidewall, is usually visible to the naked eye when inspecting the wheel, unlike a change in toe-in, which can only be detected on a specialist measuring rig. These types of damage often occur together following the same incident, which is why a full inspection after a heavy impact should cover the wheel, suspension and wheel alignment simultaneously, rather than just one of these components.
What do we check following a report of a kerb impact?
Following a report of a kerb impact, we first assess the condition of the wheel rim and tyre for visible damage, and then we check the suspension and steering system for play, which could indicate mechanical damage beyond mere wheel alignment. If these components are in good condition, we carry out a wheel roll test and, if necessary, a full wheel alignment check to determine whether, and to what extent, the wheel alignment deviates from the manufacturer’s recommended settings. This sequence helps to avoid a situation where we correct the toe-in, even though the real problem is a damaged suspension component that needs replacing.
When should you go for a check-up straight away, and when can you wait?
After a heavy impact with a kerb – felt as a distinct jolt in the steering wheel or an unusual noise at the moment of contact – it is worth scheduling an inspection as soon as possible, rather than waiting for visible symptoms to appear. In the case of a slight scrape with the wheel, without a noticeable jolt, you can monitor the car’s behaviour over the following days and arrange an inspection if the car starts to pull to one side or other worrying signs appear. We operate 24 hours a day, seven days a week, so if you feel a distinct jolt after an impact, there’s no need to wait until the next working day to have your suspension checked.
Summary
- Hitting a kerb can alter the wheel alignment even without visible damage to the rim or tyre.
- Symptoms of misaligned suspension can be delayed and only appear after some time.
- A steering wheel that pulls to one side is not proof that the suspension has not been affected.
- After a heavy impact, it is worth checking the wheel rim, tyre, suspension and wheel alignment together, rather than separately.