How do potholes damage a car beyond the tires?

Why potholes hit so hard

The damaging part is the far edge, not the hole. A tire drops into the void and then strikes the vertical lip on the way out, which loads the wheel and suspension with a sharp impact concentrated in a very short distance.

Suspension is designed to absorb vertical movement over travel. A pothole edge is closer to a hammer blow — high force with almost no distance to dissipate it — so the energy goes into the wheel, the strut, and the mounting points rather than being absorbed.

Low-profile tires make it worse. Less sidewall means less cushion between the road and the rim, which is why larger wheels on late-model vehicles produce more bent rims than the smaller wheels of twenty years ago. Heavier vehicles, including EVs, add more force to the same impact.

What actually gets damaged

The damage list runs well past the tire, and most of it is invisible from outside the car:

• Bent or cracked wheel — steel wheels bend, aluminum wheels crack, and a cracked wheel loses air
• Tire sidewall bulge, which is internal cord damage and a blowout risk even though the tire holds air
• Blown or leaking struts and shocks, and damaged strut mounts and bearings
• Bent control arms, tie rods, or steering knuckles, which put the alignment permanently out
• Broken coil springs, often not noticed until a clunk appears
• Damaged wheel bearings and CV joints
• Cracked lower bumper covers, air dams, and underbody aerodynamic shields torn loose
• Damaged exhaust hangers and dented exhaust components
• On a hard hit, movement at the subframe mounting points in the unibody structure

The alignment and sensor consequences

A pothole hit that changes camber or toe by a small amount will chew through a tire in a few thousand miles, and it will pull the car to one side long before you see the wear.

The less obvious consequence is driver assistance. Forward-facing cameras and radar are aimed relative to the vehicle’s thrust line and ride height, so an alignment change or a suspension repair can put them out of aim. Many manufacturers require a calibration after an alignment or a suspension component replacement for exactly this reason.

Steering angle sensors also need to be reset after alignment work on most vehicles, because stability control uses that sensor to know where you are pointing the wheels.

This is the part that surprises people about a pothole. It is not just a tire and a wheel — a single hard hit can put a car out of alignment, out of sensor aim, and out of the condition its safety systems were calibrated in, all at once.

What to check after a hard hit

Some of it you can check in a parking lot, and some of it needs the car on a rack. Start with the obvious and pay attention over the next few days.

• Look at the wheel for a flat spot, a lip that is no longer round, or a crack on the inner barrel
• Look at the tire sidewall for a bubble or bulge — that tire needs to come off the road
• Note whether the steering wheel is still centered when driving straight
• Note whether the car pulls to one side on a flat road
• Listen for a new clunk over bumps or a vibration at a specific speed
• Check for any driver-assist warning, or adaptive cruise and lane keeping behaving differently
• Look underneath for a hanging shield, a torn liner, or fresh fluid
• Check tire pressures, since a rim can be bent enough to leak slowly

Minnesota pothole season and insurance

Potholes form when water gets into cracks in the pavement, freezes, expands, and lifts the surface, then traffic breaks the weakened section out. Minnesota runs that cycle constantly from late winter into spring, which is why our worst road conditions are also our worst car damage weeks.

They are also hardest to avoid exactly when they are worst. A pothole full of meltwater looks like a puddle, and a fresh one has a square, sharp edge rather than a worn one. If you cannot avoid it, brake before it rather than through it and let the suspension travel do its job.

On the insurance side, pothole damage is a collision claim under most policies — you struck an object — so it is subject to your deductible and, on your own claim, can be treated as at-fault. Weigh the repair cost against the deductible before filing.

Claims against a city or county for pothole damage exist but are rarely paid, because most jurisdictions have to have had notice of the specific defect and a reasonable chance to repair it. Reporting the pothole is still worth doing, if only so the next driver does not hit it.

What we look at

For a hard pothole hit we start where the force went: wheel, tire, suspension, and steering, then structure. If anything on the underbody moved, laser measuring compares the vehicle against factory specification and you get documented before-and-after numbers.

Cracked bumper covers and torn shields get repaired or replaced, and where the manufacturer requires a calibration after alignment or suspension work, it is written into the repair plan and performed as part of the job.

If you hit something hard enough to worry about it, that is reason enough to have it checked. Send photos or call (651) 460-9996.