Tires wear, but uneven tread deterioration will hasten your need for replacement. Outside edge wear (as well as inside-edge wear) are the two most dreadful and costly forms of wear.
Read on to discover more about the underlying causes of outside tire wear and how to mitigate it going forward. After all, no one wishes to prematurely condemn their tires any faster than absolutely necessary.
What Causes Outside Tire Wear?
Heavy outside tire wear can be caused by a variety of factors, all of which require special attention to detail. Having a good understanding of each potential source of outside tire wear can be useful when trying to correct the problem at hand.
Here are a few of the most common contributors to outside tire wear.
#1. Under-Inflation Wear.
An under-inflated tire will very quickly show premature wear on the outside edges of its tread. This is because the outside “shoulder” of a tire’s tread is subjected to extra loads when operated at a lower than preferred pressure, and therefore, in an under-inflated state.
And, the inside edge of an under-inflated tire will often show valid signs of premature wear as well.
This situation can be easily corrected by properly inflating your tires to the specification of your vehicle’s manufacturer and taking proper steps to avoid dry rot.
So, if your TPMS light comes on indicating low tire pressure, but a simple visual inspection shows no clear flat tire, you may want to rethink driving your vehicle. Excessive outer tread wear is simply a common sign of driving your vehicle with low tire pressure. even just a few PSI.
#2. Excessive Positive Front Camber.
A camber measurement is a measure of the inward/outward tilt of a vehicle’s tires as compared against a vertical axis. Any excessive camber will cause irregular tire wear, most notably premature outer/inner edge wear.
In a case of excessive positive camber, outer edge tire wear can often be traced back to excessive positive camber. In most instances, this condition can typically be corrected through a simple alignment.
However, one may wish to, as well, rotate their tires in an effort to share any uneven wear sustained over time.
#3. Incorrect Toe Adjustment.
A toe adjustment measurement is the inward/outward angle of the front or rear tires of a vehicle, as viewed from a horizontal angle.
Incorrect toe adjustment can cause many issues, but the most noteworthy is unusual or rapid tire wear. In many cases, this wear pattern is primarily along a tire’s edge.
In order to correct this condition, the vehicle would be required to be aligned by certified personnel to mitigate further tire wear. Subsequently, unless their tires are too worn to rotate, it is prudent to rotate the affected tires.
If an incorrect toe is determined to be the cause of a tire’s irregular wear, one may also consider inspecting the front end of the vehicle for wear symptoms.
#4. Worn Suspension Components.
In some instances, worn suspension parts may also cause a tire’s outer edges of the tread to wear excessively.
In general, suspension-related tire wear is most often seen as cupping, or scalloping, within the tire’s tread pattern. With this wear, the tire can resemble peeling away tread in a definite pattern.
Where wear of this type is likely to have been experienced by the entire tire, it usually first appeared visible along the tire’s outside edge.
To repair wear of this nature, requiring replacement of a worn-out suspension component, etc., i.e., shocks and struts.
#5. Damage to Components.
Any type of irregular tire wear can also be attributed to damage sustained to a vehicle’s key suspension and/or steering components. Damage does not necessarily imply an accident, no matter how slight.
For example, an incident such as a curb strike at speed, under some conditions, can give rise to considerable damage to a vehicle’s suspension and or steering components.
Damage to a vehicle’s steering or suspension components can be caused by other factors, towing too much weight on a trailer, regular off-road driving, or prior incorrect installation of front-end components.
In all cases of tire wear caused by current compromised steering and/or suspension components, the damaged components must be repaired or replaced to have any chance of returning to normal tire wear.
In addition, if the performance of any steering and/or suspension components was altered prior to replacement, a front-end alignment may be required.
Identifying outside tire wear patterns
It is astonishing how often unnatural tire wear patterns occur, even though it is valuable to identify certain tire conditions in order to assess issues according to what wear pattern is present.
Feathering
Feathering is a situation where the edges of the tread ribs on the tire wear down on a diagonal angle, often the result of improper wheel alignment or excessive toe settings, which causes the inside edge of the tread bar to have a feathered, or tapering, appearance.
Cupping
Cupping, or scalloping, is are dip or cups in a tire’s tread, typically in a series. Cupping is generally due to worn or damaged suspension components leading to an uneven tire-to-road contact patch.
Edge Wear
Edge wear is the wear of the inner or outer edge of the tire tread. Edge wear is typically caused by either too high or too low tire air pressure, leading to undesirable tire-to-road contact weight distribution.
If you have edge wear, you likely have an under-inflated tire.
Patchy Wear
Patchy wear refers to irregular tire wear in random patches on the tire surface. Patchy wear is commonly caused by improper tire balance, leading to uneven tire-to-road contact.
Is It Safe to Drive on a Tire with Uneven Outer Edge Wear?
Whether or not you can drive on one or more tires that have significant outer edge wear depends on how much wear has actually taken place.
If this kind of irregular wear has just occurred, and is not too bad, you can usually fix this tire by moving it to a different wheel-end position. However, the issue must be resolved for this irregular wear to be fixed.
Conversely, any tire that has been structurally compromised through abnormal wear should be thrown away right away.
The same goes for tires that have any significant outer edge wear. If you see secondary rubber (structural non-tread rubber), or any belting, you need to stop using that tire immediately.
A tire with wear that is not symmetrical can be prone to blow-outs, which may cause you to wreck. This is particularly true if you can see the cord or belting material.
Operating on tires in that state is very dangerous and poses a high risk of injury in the event of a wreck, so regular inspection of tires is vital and can even save lives at times.
If ever in doubt, it is better to be safe and stop using a tire than to take the chance either on your safety or the safety of your family. Tires can be expensive, but they are priceless when your life is on the line.
What if one tire is wearing on the outside?
If you notice that you have one tire wearing on the outer edge, the chances are that the tire is underinflated.
Using a tire pressure gauge, check that the PSI is (or relatively close to) the manufacturer’s specifications found on the driver’s side door jamb or owner’s manual.
While that is the most likely scenario, any of the other four causes listed above could also be responsible.
Do tires wear on the outside faster?
If you are not doing any form of car racing with a custom alignment setup, your tires do not wear on the outside any faster than they should. Under normal driving conditions, your tires should wear uniformly.
But in general, the front tires (which do the most work) will wear faster (also more on the sides) than rear tires do.
Now, if you have a rear-wheel-drive car and frequent a dragstrip on Friday nights, or do burnouts or donuts, you might have other opinions on that.
How to Avoid Tires Wearing on the Outside
Proper Tire Inflation
To avoid uneven tire wear, make sure to check tire air pressure regularly. Tires naturally lose air, so it’s important to make sure it is in the recommended range provided by the manufacturer.
Running on improperly inflated tires can cause irregular wear patterns and substantially reduce traction. A good tire pressure gauge can be purchased fairly cheaply. Be sure to check for a sticker that is usually located inside the driver’s door jamb or somewhere in the owner’s manual.
Also, be aware that changes in season and temperatures can impact the air pressure in your tires.
Frequent Tire Rotation
Rotating tires often is a good way to distribute wear equally on all four wheels. You should rotate your tires every 5,000 to 7,500 miles, or every oil change, whichever comes first.
It is important to rotate tires to help ensure differences in wear patterns between the front and rear tires are minimized, which can help prolong all four tires’ lives.
Alignment Inspections
Misalignment of wheel angles often causes wear along the outer edges. Be sure to periodically check alignment, as misalignment can cause a tendency for outside tire wear.
If uneven or quick tire wear (outer edges) has been noticed, steering control is poor, or you feel your car pulling to one side, it is time to check the alignment of your vehicle.
Suspension Maintenance
The suspension system (springs, bushings, shocks, etc.) acts to evenly distribute the vehicle’s weight and create traction for the tires. Worn or damaged components of your car’s suspension can lead to irregular wear patterns.
Regular inspections and maintenance of the suspension system components (bushings, broken springs, sagging springs, bent struts and spindles, etc.) should eliminate possible sources of outside tire wear.