For those who own a car, tires are some of the most expensive things about owning a car. The cost of tires can be around $1,000 per set, and saving money by preserving their life is great, but incorrect tire wear, like cupping, reduces your mileage.
So, what is tire cupping, what are its causes, and are there any serious hazards to operating your vehicle on cupped tires?
What is Tire Cupping?
Tire cupping is an odd sort of tire wear, quite literally shaped like a dished or scalloped tread. Most often, cupping will not be limited to one area of the tread, but will follow the outside circumference of the overall tire.
Cupping is a major form of irregular tire wear, incurred on literally thousands of vehicles each year. From cars to motorcycles, virtually every vehicle will have some form of irregular tire wear.
The most common form of irregular tire wear is mechanical fatigue. However, the problem of identifying the source of this mechanical fatigue can be somewhat more involved.
Unfortunately, the risk of tire cupping often will not be resolved without mechanical intervention, and by then, in many cases, the damage is done.
So, consequently, every year, there are a significant number of tires that are otherwise impeccable tires removed from service due to extreme cupping.
What Causes Cupping on Tires?
There can be several underlying causes of tire cupping, with each cause varying in frequency and severity. Identifying and knowing about each independent cause is important in fixing tread-related problems of this nature.
Here are a few of the most frequent causes of tire cupping.
#1. Not Regularly Rotating Tires.
Tires simply do not wear evenly, and tire rotations (every 6000 miles or every 6 months is ideal for most vehicles) help lessen uneven tread wear, cupping, scalloping, and bald spots.
Tire rotations are important for every vehicle, but trucks and cargo vans are often the most prone vehicles to cupping when a tire rotation schedule isn’t followed.
Usually, the tire chains, Les Schwab and Discount Tire, will do free tire rotations if you purchased the tires through them.
Also, many oil change places (and some dealerships) offer free tire rotation with an oil change. There’s really no excuse not to rotate your tires.
#2. Worn or Damaged Suspension Components.
One of the most common causes of tire cupping is seriously worn suspension components.
A vehicle’s shocks and struts absorb vibration from the road, while preventing the tires themselves from bouncing up and down erratically down the road.
When any of these components become compromised, cupping is often right around the corner.
#3. Out of Balance Condition.
All wheels and tires have natural heavy spots, which need to be balanced out in order to have a smooth ride. This process must also occur again over the life of a tire to maintain a tire’s stability.
However, once a tire gets seriously out of balance, there is irregular wear that comes along with this. Often, as an out-of-balance tire skips across a roadway, cupping wear occurs.
#4. Tires Out of Round.
In some instances, a tire will show excessive runout, meaning a tire is out of round, and you’ll be able to notice when your tire rolls down the road as the tire has a more noticeable hop/wobble.
With tires, excessive runout generally happens when a tire twists a structural belt, is of poor construction, or simply gets worse over time to the point of excessive cupping.
#5. Poor Alignment.
An improperly aligned front end can also cause tire cupping, as the standard vehicle’s front steering and suspension allow for three individual adjustments (caster, camber, and toe), any of which may be of concern if out of spec.
In severe cases, it’s almost a guarantee that irregular tire wear occurs.
Is Tire Cupping Dangerous?
Driving on severely cupped tires can be dangerous. This is because cupped tread does not grip the road like tread with normal wear. In short, cupping reduces tread-to-pavement contact, which limits a vehicle’s traction.
The loss of traction is no different than when there is improper wear on the tire, such as inside tire wear or outside tire wear, particularly if driving in slick conditions. This is a serious safety issue that could lead to a greater chance of being involved in an accident.
Severely cupped tires should be removed from service and thrown away as soon as possible. The causes of tire cupping should also be investigated and fixed, so that they do not cause any additional irregular tire wear. If steps are not taken, it could affect your safety, and of course, others on the road.
What Do Cupped Tires Sound Like?
Cupped tires make a rather loud humming or droning sound while driving down the road. In some respects, it will sound similar to a bad wheel bearing.
The difference with cupped tires is that it will not sound any different when steering either left or right. As a side note, this noise seems to be very common with cupped all-terrain or mud tires specifically.
As tire cupping develops, the sound associated with it will only continue to get worse, potentially culminating in a deafening racket. Unfortunately, the only way to reduce this noise is by replacing the vehicle’s tires that are irregularly worn.
Can a Cupped Tire Be Fixed?
Whether cupped tires can be fixed is a circumstantial consideration. If cupping is caught early enough, some of the cupping may be minimized if a vehicle’s tires are rotated and balanced correctly onto different wheel-end positions.
Additionally, the cupping cause should have its diagnosis and correction done as soon as possible. Doing so prevents the recently rotated tires from cupping immediately
However, some tires may not be salvageable – when cupping is known to have developed continuously since new, and there are extensive variations in tread wear patterns.
In circumstances such as these, it may be best to begin fresh with new tires after properly correcting any mechanical issues.
Tire Cupping vs. Feathering
There are many people who interject cupping and feathering to describe irregular tire wear, and tire cupping and feathering are two different animals.
Cupping means an observable dishing/scallop of a tire tread contour, while feathering implies a trail of slanted wear to individual tread blocks.
The latter causes a tire tread block to be worn noticeably more on one edge of a tread block, while the other edge of a tread block likewise would be worn and upturned in its wear.
This appears as a stair-stepped block pattern across the entire tread, which is most often associated with alignment issues.
Prevention
Preventing tire cupping is perhaps the best thing that can be accomplished with regular ongoing preventive vehicle maintenance, which would typically include having a vehicle’s tires rotated and balanced regularly, and if and when a set of vehicle tires ever needs to be serviced, the vehicle’s alignment checked as well.
Having consistent preventative procedures with tires will help reduce the severity and amount of irregular wear patterns in general, including cupping.
We additionally would suggest that a vehicle’s steering and suspension components be inspected, monitored, and maintained by a professional at regular intervals and to repair any steering and suspension component found to be defective, damaged, or excessively worn.
Doing so will thereby help ensure a vehicle’s tires will be less likely to sustain needless damage, saving the public money and time.