Don’t brake in a pothole!

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Don’t brake in a pothole!

The impact

When a wheel hits a pothole, it falls into the hole and has to emerge. It is rare that the entry that causes the damage; rather it is the exit. The amount of damage depends on the diameter of the tire, the depth and length of the pothole and the speed of the vehicle. When a wheel passes over a road’s contours, most of the force exercised on the suspension is directed upward because the contact is made with the bottom of the tire. The higher up the tire the impact, the more the force of the impact tends to push the wheel both backward and upward. The smaller the diameter of the wheel, the more severe the impact, especially if the depth of the hole is the same as the diameter of the wheel.

Longer potholes cause more damage because their length means that at practically any speed, the tire risks hitting its bottom before being able to emerge. Similarly, low speed can result in damage to the vehicle’s frame or platform because, here again, the tire has time to hit the bottom of the hole.

The consequences

When a tire hits the inside of a pothole, it is pushed both backward and upward, which transmits the shock to the wheel, the suspension and the steering. The most likely results of a severe impact with a pothole are one or more of the following: loss of a hubcap, a damaged tire, a bent or broken wheel, a wheel knocked out of alignment, damaged suspension, bent steering parts, damaged shock absorbers.

Hub cap:

Because hub caps are often attached to wheels only by pressure clamps, they are easy to lose and can cost $20 to $150 each to replace.


The tire is the first to absorb the impact, and this can break its interior structure and/or tear its sidewall. Overinflation increases the risk of structural damage to a tire, whereas an underinflated tire can be broken by being squeezed between the pothole and the wheel. A new tire can cost anywhere from $70 to more than $400. Low-profile tires — with which manufacturers are increasingly equipping new cars these days — can be severely damaged by such an impact. If you have any doubts following a collision with a pothole, it would be wise to have your tire examined by a specialist, who will be able to detect a possible broken tire belt, which could pose a serious safety hazard.


It the tire does not absorb the entire shock because, for example, it is underinflated, the wheel will suffer the consequences. It may bend, crack, or break as a result of the impact and there is little likelihood of it being repairable. Thus, more often than not, it must be replaced. Of course, alloy wheels are both more fragile and more expensive. While a new steel wheel may cost $40 to $200, an alloy wheel can cost $500 and up.

Suspension and alignment:

A wheel that falls into a pothole is subject to both vertical and horizontal force. These are transmitted to the suspension, whose normal movement is vertical. If the horizontal force is significant, the suspension parts, such as the suspension arm, and steering parts, including the steering linkage, can be damaged and the wheels can be knocked out of alignment. Replacing a steering linkage can cost between $75 and $250, depending on the make of car, while a suspension arm can lighten your wallet by $150 to more than $350.

If the wheels are not realigned, tires can wear quickly and the vehicle’s handling may deteriorate noticeably. A wheel alignment can cost $50 to $150, depending on the sophistication of the steering system and the amount of damage.

Fortunately, shock absorbers are rarely broken by a collision with a pothole. The more likely result of constant driving on bad roads is shortened shock absorber life. There are ways to tell if a shock absorber is reaching the end of its useful life span. While oil leaking from a shock absorber is a bad sign, it does not necessarily mean it’s the end; a shock absorber can still last a long time. The reverse is also true, however: just because a shock absorber isn’t leaking at all does not necessarily mean it shouldn’t be replaced soon. The best way to check is to push down hard two or three times on a corner of the vehicle, then let go when the car is at its lowest point. If the car bounces twice or more, it is time to change that shock absorber. Repeat the test on all four corners of the vehicle. It is possible that the pair of shocks on the same axle will have to be replaced at once. A shock absorber can cost from $50 to upwards of $500.


Despite release from liability obtained by Quebec municipalities and the province’s Ministry of Transport in 1993, it is still possible to receive compensation in the event your vehicle incurs damage. See our automotive tip on pothole damage in Claims and Compensation. Motorists may also consult their insurance company to see if it is more advantageous to submit a claim to the company, given the deductible in their insurance policy. If you choose not to submit a claim to your insurance company, your claims history in the central claims registry, Fichier central des sinistres, should remain unchanged.

A word of advice

If you can’t possibly avoid a pothole, at least avoid braking suddenly; instead, allow the wheel to roll freely into the hole. In fact, a blocked wheel is likely to sustain much more damage than a rolling wheel. Sometimes it is better just to hit the pothole than to try to avoid it by making a manoeuvre that could cause a more serious accident. And don’t try to recover a lost hubcap on a busy highway or you may be hit by a passing vehicle. If you must do so, make sure there is no danger to yourself or other road users. Finally, if you must stop to inspect damage to your car, ensure that you are parked in a safe place.

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