Speed bump and pothole damage is one of the most common reasons a car that drove fine last week suddenly pulls, shakes or clunks. Your tires, wheels and suspension are built to absorb bumps, but a sharp-edged pothole or a speed bump taken too quickly can deliver more force than those parts are designed to handle in one blow.
Some damage is obvious right away, like a flat tire. Other damage, like a bent control arm or a worn strut mount, can take weeks to show up. If something feels different after a hard hit, a suspension and steering inspection can find the problem before it spreads to other parts.
What a hard impact can damage
Tires and wheels
When a tire drops into a pothole and slams against the far edge, the sidewall can get pinched between the rim and the pavement. That can break the cords inside, leaving a bulge in the sidewall, or cut the tire outright. Wheels can bend at the lip, which may cause a slow air leak or a vibration at highway speed. Alloy wheels can crack in severe cases.
Alignment and steering parts
A strong jolt can shift the alignment angles or bend a tie rod. Signs include a steering wheel that sits off-center when you drive straight, a pull to one side, or tires that start wearing on one edge. Our article on the dangers of misaligned wheels explains why that is worth correcting quickly.
Suspension components
Shocks and struts, coil springs, ball joints, control arm bushings and sway bar links all take part of the force. Repeated hard hits can speed up their wear, and a single severe one can bend an arm or break a spring. Clunks over smaller bumps, a bouncier ride or a corner that sits lower than the others are clues.
The underside of the car
Speed bumps are less likely to hurt the suspension when taken slowly, but low vehicles can scrape on them. That can tear plastic splash shields, dent the oil pan, or bend exhaust pipes and hangers. A damaged exhaust may start rattling or sound louder, and a dented oil pan can eventually leak.
How to drive over speed bumps
- Slow down early. Do your braking before the bump, not on top of it.
- Come off the brake just before the front wheels reach it. Braking pushes the nose down, compressing the front suspension and lowering the bumper.
- Approach straight on so both wheels on an axle rise together, unless your car is very low and the bump is steep. In that case, a slight angle can keep the front lip from scraping, but go very slowly.
- Do not accelerate until the rear wheels are over. Hitting the gas too early drops the rear and can scrape the exhaust.
How to reduce pothole damage
- Leave following distance. If you are close behind another vehicle, you cannot see the road surface in time to react.
- Be wary of puddles. After heavy rain, standing water can hide a deep hole. If you can safely avoid driving through it, do.
- Do not swerve. Moving suddenly into another lane or onto the shoulder is more dangerous than hitting the pothole. If you cannot avoid it, slow down and keep the wheel straight.
- Keep tires properly inflated. An underinflated tire has less cushion between the rim and the edge of the hole. Use the pressure on the label inside the driver’s door jamb, not the maximum printed on the tire.
- Grip the wheel firmly so the impact does not jerk the steering out of your hands.
What to check after a hard hit
Once you are safely parked, take a quick look around the car. Check each tire’s sidewall for bulges, cuts or scuffs, and look at the wheel lips for bends. Watch for a tire pressure warning light over the next day or two, since a damaged wheel or tire may leak slowly.
On your next drive, pay attention to how the car feels. A steering wheel that is no longer centered, a pull, a new vibration, a knock over bumps or a scraping sound are all reasons to have it inspected. These symptoms can overlap with other issues covered in our guide to common suspension problems, so it helps to note exactly when they happen.
If a tire is bulging, do not keep driving on it. Put on the spare if you can do so safely, and have the tire, wheel and alignment checked. Our tire and alignment services cover tire inspection, balancing and alignment.
Get it checked in Hermitage
If a pothole or speed bump left your car feeling different, Music City Auto Repair can look over the tires, wheels, steering and suspension, explain what we find and give you an estimate before any work begins. Request an appointment online or call 615-600-5994.
Frequently asked questions
Should I brake while driving over a pothole?
Slow down before you reach it, then ease off the brake just before the tire drops in. Braking hard during the impact compresses the front suspension and puts more of the hit into the tire, wheel and suspension parts. Never swerve into another lane to avoid one.
What does a bulge on a tire sidewall mean after hitting a pothole?
A bulge means the internal cords of the tire have been broken and air is pushing against the outer rubber. The tire can fail suddenly, so replace it with the spare and have it inspected. A sidewall bulge cannot be repaired.
Can scraping a speed bump damage the underside of my car?
Yes. Depending on the vehicle, scraping can crack a plastic air dam or splash shield, dent the oil pan, or bend exhaust pipes and hangers. If you hear a hard scrape, look for drips under the car and listen for new exhaust noise or rattles.
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