Your
tyres are often the first indication that something is wrong with
your car.
The trick is reading the signals.
Let's start with the basics: Obviously you can't read the signals if you rarely inspect your tyres. So first, check the tyre pressure at least once a month. tyres lose 1 psi each month under normal operating conditions; buy an air compressor and get used to the idea of airing them up. A compressor will pay for itself; fuel economy drops when tyre pressure drops, and many gas stations now charge for air. Don't just look at the tyre, feel it. Run your fingers along the tread, as many irregularities are more easily felt than seen.
Do your due diligence and you may detect a problem before the tyre is ruined. And remember, your tyres are your only connection to the road, and they're one of the most overlooked safety items.
What are your worn tyres trying to tell you? Let's look at some weirdly worn rubber to find out.
Let's start with the basics: Obviously you can't read the signals if you rarely inspect your tyres. So first, check the tyre pressure at least once a month. tyres lose 1 psi each month under normal operating conditions; buy an air compressor and get used to the idea of airing them up. A compressor will pay for itself; fuel economy drops when tyre pressure drops, and many gas stations now charge for air. Don't just look at the tyre, feel it. Run your fingers along the tread, as many irregularities are more easily felt than seen.
Do your due diligence and you may detect a problem before the tyre is ruined. And remember, your tyres are your only connection to the road, and they're one of the most overlooked safety items.
What are your worn tyres trying to tell you? Let's look at some weirdly worn rubber to find out.
Center Wear
It
Looks Like: Your
tyre is worn down only in the middle.
The Diagnosis: This tyre was overinflated, causing the center ring only to contact the road. Consequently, whoever drove this car had only a fraction of the rubber contacting the asphalt, so his or her traction suffered.
To find the correct tyre pressure, check the door placard or the owner's manual. Check the pressure when the tyres are cold, before you start driving. Some people claim that you should overinflate tyres to reduce rolling resistance and increase fuel economy. But that's a fool's game. You might save some fuel, but you'll pay more in prematurely worn tyres.
If your pressure is correct but you still see center wear, this could indicate that the wheel and tyres are not properly matched. There is one caveat here: Anthony, product information specialist at TyreTraders.com, says that some rear-wheel-drive vehicles can produce center wear on certain tyres, even if they're properly aired up and maintained. But that's true only for high-powered sports cars.
The Diagnosis: This tyre was overinflated, causing the center ring only to contact the road. Consequently, whoever drove this car had only a fraction of the rubber contacting the asphalt, so his or her traction suffered.
To find the correct tyre pressure, check the door placard or the owner's manual. Check the pressure when the tyres are cold, before you start driving. Some people claim that you should overinflate tyres to reduce rolling resistance and increase fuel economy. But that's a fool's game. You might save some fuel, but you'll pay more in prematurely worn tyres.
If your pressure is correct but you still see center wear, this could indicate that the wheel and tyres are not properly matched. There is one caveat here: Anthony, product information specialist at TyreTraders.com, says that some rear-wheel-drive vehicles can produce center wear on certain tyres, even if they're properly aired up and maintained. But that's true only for high-powered sports cars.
Cracking and Bulging
It
Looks Like: Pretty
self-explanatory.
The Diagnosis: This usually comes from hitting a pothole, curb, or debris. Underinflation and overinflation put tyres at a greater risk of damage from impacts.
Large cracks in the sidewall that runs along the rim are either impact-related or caused by chronic underinflation. Numerous small cracks in the sidewall or tread blocks come from exposure to the elements and age.
Bulging is what looks like a pimple in the tyre, most often in its sidewall. It happens when there's an impact that causes internal damage, but the damage doesn't show up until weeks or months later. With cracks or with bulging, you're looking at buying a replacement. "[The tyre] should be removed from service, regardless of the cost," Anthony says. "Eventually, it will fail."
The Diagnosis: This usually comes from hitting a pothole, curb, or debris. Underinflation and overinflation put tyres at a greater risk of damage from impacts.
Large cracks in the sidewall that runs along the rim are either impact-related or caused by chronic underinflation. Numerous small cracks in the sidewall or tread blocks come from exposure to the elements and age.
Bulging is what looks like a pimple in the tyre, most often in its sidewall. It happens when there's an impact that causes internal damage, but the damage doesn't show up until weeks or months later. With cracks or with bulging, you're looking at buying a replacement. "[The tyre] should be removed from service, regardless of the cost," Anthony says. "Eventually, it will fail."
Cupping (Also Called Scalloping)
It
Looks Like: A
pattern of alternating hills and valleys
The Diagnosis: It happens when worn or damaged suspension components cause the tyre to bounce as it travels, coming down harder on some spots of the tyre than others. Bad shock absorbers are the usual cause, though anything that connects the wheel to the rest of the car could be a culprit.
Be careful with your diagnosis, though. Even tyre shops sometimes incorrectly identify feathering or heel-toe wear as cupping. A wheel that is out of balance may also cause cupping or bald spots to form, though there will be fewer hills and valleys than you'd see with cupping caused by a failed shock absorber.
The Diagnosis: It happens when worn or damaged suspension components cause the tyre to bounce as it travels, coming down harder on some spots of the tyre than others. Bad shock absorbers are the usual cause, though anything that connects the wheel to the rest of the car could be a culprit.
Be careful with your diagnosis, though. Even tyre shops sometimes incorrectly identify feathering or heel-toe wear as cupping. A wheel that is out of balance may also cause cupping or bald spots to form, though there will be fewer hills and valleys than you'd see with cupping caused by a failed shock absorber.
Diagonal Swipe
It
Looks Like: Cupping
or scuffing, but in a diagonal pattern.
The Diagnosis: This tyre trouble is most often seen on the rear tyres of a front-wheel-drive car with an incorrect toe setting. Insufficient tyre rotation intervals may also cause a diagonal swipe. A third possibility: If you frequently carry heavy loads in the trunk or cargo area of a vehicle, that may change the geometry of the suspension, leading to a diagonal swipe.
The Diagnosis: This tyre trouble is most often seen on the rear tyres of a front-wheel-drive car with an incorrect toe setting. Insufficient tyre rotation intervals may also cause a diagonal swipe. A third possibility: If you frequently carry heavy loads in the trunk or cargo area of a vehicle, that may change the geometry of the suspension, leading to a diagonal swipe.
Outer-Edge Wear
It
Looks Like: The
inside and outside edges are worn down; the middle is not.
The Diagnosis: This is a telltale sign of underinflation. Too little pressure is arguably the most dangerous condition for a tyre, as it will flex more and the heat that builds up could cause a blowout. (Remember the Ford Explorer Firestone mess? The cause was mainly underinflated tyres.) And an underinflated tyre won't absorb bumps well and may knock the front end out of alignment or damage the suspension.How to Avoid Underinflation: Again, keep an eye on your tyre pressure by checking it monthly. Don't rely on the car's tyre-pressure monitoring system to let you know when a tyre is low on air. "[The warning system's] threshold is typically 25 percent underinflated," Anthony says. This means a tyre that should be at 28 psi could be down 22 psi before you see a warning light. And that could be low enough for you to destroy a tyre.
The Diagnosis: This is a telltale sign of underinflation. Too little pressure is arguably the most dangerous condition for a tyre, as it will flex more and the heat that builds up could cause a blowout. (Remember the Ford Explorer Firestone mess? The cause was mainly underinflated tyres.) And an underinflated tyre won't absorb bumps well and may knock the front end out of alignment or damage the suspension.How to Avoid Underinflation: Again, keep an eye on your tyre pressure by checking it monthly. Don't rely on the car's tyre-pressure monitoring system to let you know when a tyre is low on air. "[The warning system's] threshold is typically 25 percent underinflated," Anthony says. This means a tyre that should be at 28 psi could be down 22 psi before you see a warning light. And that could be low enough for you to destroy a tyre.
Feathering
It
Looks Like: Feathered
tread blocks are shaped like a series of ramps in a directional wear
pattern that goes sideways across the tyre. The lower edges of the
ramps are rounded while the higher edges are sharp. If you can't tell
by looking, run your hands across the tread blocks.
The Diagnosis: Most often, feathering means the car's toe setting (a measure of the car's alignment) is off. If the toe setting is correct, a worn or damaged suspension bushing could be causing the car's alignment to shift as you drive. Check for worn or damaged ball joints and wheel bearings as well.
The Diagnosis: Most often, feathering means the car's toe setting (a measure of the car's alignment) is off. If the toe setting is correct, a worn or damaged suspension bushing could be causing the car's alignment to shift as you drive. Check for worn or damaged ball joints and wheel bearings as well.
Flat Spots
It
Looks Like: One
single spot on the tyre is more worn down than the rest.
The Diagnosis: Single spots of heavy wear show up on the tyres when a car has been in a skid—say, the driver saw a deer on the highway and slammed on the brakes. A car without an antilock braking system is more likely to lock up its tyres under heavy braking, which can cause a flat spot.
Also, cars that are parked for extended periods of time risk getting flat spots where the weight of the car has deformed the patch of tyre contacting the ground. Unlike flat spots resulting from a skid, these show no additional tread wear—but nonetheless, the tyre is misshapen. Although radial tyres can have this problem, bias-ply tyres are more prone to getting flat spots from sitting too long, especially if the tyres are sitting in any kind of corrosive liquid, such as gasoline or antifreeze.
The Diagnosis: Single spots of heavy wear show up on the tyres when a car has been in a skid—say, the driver saw a deer on the highway and slammed on the brakes. A car without an antilock braking system is more likely to lock up its tyres under heavy braking, which can cause a flat spot.
Also, cars that are parked for extended periods of time risk getting flat spots where the weight of the car has deformed the patch of tyre contacting the ground. Unlike flat spots resulting from a skid, these show no additional tread wear—but nonetheless, the tyre is misshapen. Although radial tyres can have this problem, bias-ply tyres are more prone to getting flat spots from sitting too long, especially if the tyres are sitting in any kind of corrosive liquid, such as gasoline or antifreeze.
Heel-Toe
It
Looks Like: Feathering,
only the ramps run front-to-back along the tyre rather than
side-to-side. The leading edge of the tread blocks will be worn
smooth while the trailing edge will be sharp.
The Diagnosis: "[It's] definitely one of the most common conditions we see," Anthony says. "Because it's so common, a lot of people think it's normal." Heel-toe wear is typically a symptom of insufficient tyre rotation intervals. So check your car's maintenance schedule and make sure you keep up. Misalignment or worn or damaged suspension bushings, ball joints, and wheel bearings can also cause heel-toe wear.
The Diagnosis: "[It's] definitely one of the most common conditions we see," Anthony says. "Because it's so common, a lot of people think it's normal." Heel-toe wear is typically a symptom of insufficient tyre rotation intervals. So check your car's maintenance schedule and make sure you keep up. Misalignment or worn or damaged suspension bushings, ball joints, and wheel bearings can also cause heel-toe wear.
Single-Side Wear
It
Looks Like: One
side of your tyres wears down faster than the other.
The Diagnosis: The car's camber setting is likely off, causing the tyre to lean too far to one side. Take the car for an alignment adjustment. Worn or damaged springs, ball joints, and suspension bushings can also cause single-side wear as could carrying heavy loads frequently, incorrect toe setting, and insufficient tyre-rotation intervals. Some performance cars leave the factory with enough camber to induce single-side wear, but that's rare.
The Diagnosis: The car's camber setting is likely off, causing the tyre to lean too far to one side. Take the car for an alignment adjustment. Worn or damaged springs, ball joints, and suspension bushings can also cause single-side wear as could carrying heavy loads frequently, incorrect toe setting, and insufficient tyre-rotation intervals. Some performance cars leave the factory with enough camber to induce single-side wear, but that's rare.
Tread-Wear Indicators
They
Look Like: Ridges
between the tread blocks. They sit tucked away between the treads
where they can't contact the road.
The Diagnosis: When the tread wears down to the point that it is flush with the indicators, the tyre has reached the end of its life. But depending upon the driving conditions you usually encounter, you may not want to wait for the indicators to become flush with the tread.
The tread depth of a typical tyre is 11/32 inch, and those channels are there to funnel out water and prevent hydroplaning. The tread-wear indicators are 2/32 inch high, but Anthony recommends no less than 5/32 to 6/32 inch of tread for snow and 4/32 inch of tread for rain or sleet. Wet-weather performance declines significantly after 4/32 inch, so replace the tyre before its indicators become flush with the tread block.
The Diagnosis: When the tread wears down to the point that it is flush with the indicators, the tyre has reached the end of its life. But depending upon the driving conditions you usually encounter, you may not want to wait for the indicators to become flush with the tread.
The tread depth of a typical tyre is 11/32 inch, and those channels are there to funnel out water and prevent hydroplaning. The tread-wear indicators are 2/32 inch high, but Anthony recommends no less than 5/32 to 6/32 inch of tread for snow and 4/32 inch of tread for rain or sleet. Wet-weather performance declines significantly after 4/32 inch, so replace the tyre before its indicators become flush with the tread block.
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