Repair And Fix it

A good diagnostician is something of a Car Whisperer, one who can pick up on the tiniest of clues to intuit both the cause of a problem and the avenue to its solution. Tire cupping isnt the most common wear pattern out there, but it is one of the most serious and telling in terms of diagnosing the chassis condition.

Cupping

In terms of tire wear patterns, "cupping" ers to a series of regular dips appearing in the outer edge of a tires tread. Also called "scalloping," these dips look as though someones taken shallow scoops out of the rubber with the worlds most sinister ice cream scooper. This sort of cupping shouldnt be confused with the cupping that often occurs on large drag tires. In this context, cupping happens when the tires inflation pressure is too low and the center of the tire curves upward or "cups" at high speed.

Cupping Causes

Cupping is a sign of rapid tire bounce or side-to-side oscillation. Theres no one single cause behind such bouncing or oscillations; any component that connects the wheel to the car is suspect. Worn shock absorbers will fail to control wheel movement, allowing the tires to bounce and cup the tread. Suspension bushings and ball joints are secondary suspects, followed by wheel bearings and steering end-links. The last two, however, should exhibit noticeable symptoms -- vibration through the steering wheel and chassis -- well before cupping becomes an issue.

Argument 1 -- Driving on Cupped Tires

Some contend that cupping isnt necessarily a death sentence for tires, provided that the lowest point in the scallops dont extend past the tires lowest safe wear zone. After youve fixed whats causing the cupping, the high points in the scallops will wear far more quickly than the low points, which should smooth them out over time. Rotating the tires may help to speed the smoothing, since doing so will at least change the frequency of oscillation acting upon that tire.

Argument 2 -- Not Driving on Cupped Tires

While it is true that fixing the problem and driving on cupped tires may eventually smooth them out, the fact is that the low points in the scallops will continue to wear just like the high points. Granted, theyll wear more slowly, but even with the best-case scenario, youre looking at a tire with a serious -- if smooth -- bald strip around the edge. From this perspective, any cupping at all is the death knell for your tire and a sign that it needs replacement ASAP.

Conclusion

Provided that youve replaced the worn shocks, bushings or relevant suspension component, driving on a cupped tire will eventually smooth it out to some extent. But thats like saying that sooner or later the wind will eventually erode mountains. True, it will, but itll also erode the valleys between the mountains and create low-lying dips in the landscape. Its a game of time and specific conditions, and one youre probably going to lose. Considering the likelihood and consequences of tire failure after cupping, youre best off replacing the cupped tire sooner rather than later.

You see them every day as you drive down the highway, giant vehicles that are used to distribute our goods and food. As drivers on the road we are extra caul not to get in the way of these trucks. As it is, we see so many accidents involving semi trucks because they are big and bulky. It is important that the driver is in-tune with his truck because even the smallest issue can cause a giant problem. This is why it is so important that the tires on these semi trucks are balanced correctly. This job requires the use of specialized truck tire tools. It should take you about an hour to balance your semi truck tires.

Instructions

1

Park your semi truck on level ground and set the brakes.

2

Block the front and back side of one of the tires you are not working on yet by setting one of the 4x4 blocks in front of a tire and one behind the same tire.

3

Jack up one of the wheels by positioning the big rig jack under the axle and jacking it up. Slide the jack stand under the axle for extra security.

4

Remove the lug nuts with the lug nut wrench by placing the end over the nut and turning the nut counterclockwise.

5

Inspect the operation of the truck bubble balancer. Notice how it works with the plate on top. You will see that there is a bubble in the middle of the balancer. This bubble area looks very much like a carpenters level. You will also see that the balancer has a control lever on the side. This is used to raise the wheel into the balancing mode.

6

Place the semi tire on the balancer plate so that you can see the bubble area through the center of the wheel. Push the lever to raise the tire into the balancing mode.

7

Notice the position of the bubble. The idea is to get that bubble into the center. Lay wheel weights on the tire until you get the bubble in the middle.

8

Install the wheel weights using the weight hammer at the locations on the wheel that center the bubble.

9

Replace the tire on the truck and install the lug nuts with the big rig lug wrench.

10

Remove the jack stand and lower the jack. Repeat for the other tires on the truck.