Hit a Kerb? How It Can Affect Wheel Alignment

Short answer: a solid kerb strike can knock a wheel out of alignment, and it can also bend the rim, damage the tyre’s inner sidewall, or all three at once. Alignment is the cheapest of those to fix and the easiest to spot. The rim damage is the one people miss, because the outside of the wheel can look fine while the inner flange is bent. If the car pulls, the steering wheel sits off-centre, or you feel a new vibration at 80 to 100 km/h, get the wheels checked before the tyres wear out unevenly and you are buying rubber as well.

Kerb strikes are the single most common wheel damage we see in Five Dock. Narrow Inner West streets, angled parking on Great North Road, roundabouts in Drummoyne and Abbotsford, and reversing into a gutter you cannot see over a bonnet. It is an ordinary event with a set of consequences worth understanding before you decide whether to do anything about it.

What actually happens to a wheel when you hit a kerb?

Three things can move, in rough order of how easily they move.

The alignment angles. Toe is the most sensitive. A knock to the front wheel can shift toe by a fraction of a degree, which is enough to scrub the tyre and pull the car. Camber and caster can also shift if the strike was hard, and a really hard hit can bend a control arm or a tie rod rather than just moving an adjustment.

The rim. Alloy wheels are cast or forged aluminium and they deform rather than spring back. Kerb rash on the outer lip is cosmetic. A bend in the inner flange, where the tyre bead seals, is not: it causes a slow air leak and a vibration.

The tyre. A pinch between the kerb and the rim can bruise the sidewall internally. That damage does not always show on the outside and it is not repairable.

How do I know if hitting the kerb affected my alignment?

Drive it and look at it. Four signals, in order of reliability:

1. The steering wheel is no longer centred when the car is tracking straight. This is the clearest single sign.
2. The car pulls to the left or right on a flat, straight road when you ease off the wheel. Test it somewhere safe and level; road camber alone will cause a slight drift to the left, so do not read a small drift as a fault.
3. Uneven wear on one tyre edge. Run your hand across the tread from inside to outside. Feathering, or the inner shoulder wearing faster than the rest, is a toe problem.
4. A vibration that was not there before. If it comes in at speed and is felt through the steering wheel, suspect a bent rim or a thrown balance weight rather than alignment.

A vibration is a different fault to a pull, and it is worth being precise about that, because the two send you to two different jobs. A pull is wheel alignment. A vibration is usually a balance or a rim problem, and that is rim repair in Five Dock.

Can a kerb bend a rim without leaving a mark?

Yes, and this is the part worth taking seriously. The outer face of an alloy wheel is the part that takes the visible scrape. The inner flange, behind the spokes and hidden by the tyre, is where the wheel usually bends, because that is where the leverage is.

A bent inner flange typically presents as:

• a tyre that loses two or three PSI a week with no puncture to find
• a vibration at highway speed that balancing does not fully cure
• a bead that will not reseal cleanly when the tyre is refitted

That last one is why the damage often gets found in a tyre shop rather than in a driveway. Once the tyre comes off the rim, the bend is obvious. Before that, it is not.

We straighten bent rims here rather than sending them out, which is why the diagnosis and the fix happen in the same visit. If you want to understand where the decision line sits between fixing and replacing a wheel, we have written that up separately: rim repair versus replacement.

Does kerb rash need repairing, or is it just cosmetic?

Kerb rash on the outer lip is cosmetic while the damage stays in the paint and the top layer of alloy. Two reasons people fix it anyway, and both are legitimate:

• Resale and lease return. Four kerbed wheels are a visible deduction at trade-in and a chargeable item on a novated lease return.
• Corrosion. Once the protective coating is broken, exposed aluminium oxidises. Salt air on the coast accelerates it. The white powdery bloom you see on older kerbed wheels is that process, and it eventually reaches the bead seat.

Deep gouges that reach into the flange are no longer cosmetic. If you can catch a fingernail in a gouge on the lip edge, get it looked at. Pricing sits in what kerbed wheel repair costs in Sydney.

How soon should I get it checked?

Sooner is cheaper, and this is the practical argument rather than a scare line. A misaligned front end scrubs tread off the inner shoulder continuously. Once the shoulder is down past the wear indicators, alignment no longer saves the tyre; you are buying a tyre and then paying for the alignment anyway.

Our rule of thumb in the workshop: if you hit the kerb hard enough to make a noise you noticed, get it checked in the next week or two. If the car pulls or the wheel is off-centre, get it checked now, because it is already wearing rubber.

What a proper post-kerb check looks like

If you bring a car in after a kerb strike, this is the sequence that answers the question properly:

1. Visual on all four wheels, inside and out, with the wheel turned to full lock so the inner flange is visible.
2. Pressure check and a leak test on the struck wheel.
3. Tyre inspection for sidewall bulges, bruising and bead damage.
4. A four-wheel alignment measurement, not just a front toe adjustment, because a rear thrust angle problem makes the steering wheel sit crooked no matter what the front does.
5. A balance check if there is any vibration.

Steps 1 to 3 take a few minutes and will tell you whether steps 4 and 5 are needed at all. Ask for the before-and-after alignment printout; a shop that will not show you the numbers is asking you to take alignment on faith.

Frequently asked questions

Can hitting a kerb cause a wheel alignment problem straight away? Yes. Toe can shift on a single impact. There is no delay and no bedding-in period.

Will a bent rim always leak air? No. A small bend can vibrate without leaking, and a bend at the bead seat can leak without vibrating. The two symptoms are independent.

Is a kerbed alloy wheel dangerous to drive on? Cosmetic rash is not. A bent flange, a crack, or a bruised tyre sidewall is, because all three can fail without warning at speed. Cracks in particular are not repairable by straightening.

Can you repair a kerbed wheel without removing the tyre? Cosmetic lip refinishing can sometimes be done with the tyre on. Straightening a bend cannot, because the rim has to be trued on a machine.

Do I need an alignment after a rim repair? Not because of the repair itself. You need one if the impact that damaged the rim also moved the suspension geometry, which it often did.

Get it looked at

If you have kerbed a wheel anywhere around Five Dock, Drummoyne, Abbotsford, Canada Bay or Burwood, bring the car in and we will tell you which of the three problems you actually have before you spend anything. We do the alignment and the rim straightening on site, so you are not chasing two businesses for one kerb.

Call the workshop or drop in at 18 Spencer Street, Five Dock. If you are local, here is what we cover for wheel and tyre work for Drummoyne drivers, and if the kerb also took a chunk out of the tyre, tyre repair is the page you want.