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Tire Vibration
Have had tire vibration since I purchased my coach about 1 1/2 years ago. Found out there were beads inside, had those removed and Centramatics installed. Still had vibrations, had Centramatics removed and wheels lead balanced. Still have vibration, tires had also been rotated on the rims with no better results.
JoSam’s in Orlando has installed 3 top hat nuts on each wheel to center the rims a little better and shaved the tires a little to get them back to being a little more round. Defiantly a big improvement.
As Jon has noted in past post, the tire was not centered when inflated on the rim at some point in the past and now I have to deal with the balance issue. I remember past post discussing tires (especially the bigger ones) should be inflated laying horizontal on the floor versus hanging vertically because the shear weight of the tire hanging will probably prevent it from seating centered on the rim. I discussed this with JoSam rep and he agreed, but said OSHA requires ALL tires to be inflated (during mounting) in a tire cage which hangs the tire and rim vertically hence often causing the unwanted issue I have experienced.
So when the day comes that I get new tires on the rims how do I prevent the same issue when tire shops have to deal with OSHA mandates when mounting?
Chuck
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
11 Replies
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I don’t know if it’s legal, but my tire shop seats the beads horizontally with wheel on a bucket and then places in cage for completing inflation.
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Joel, your tire shop is seating the tire bead exactly how it is to be done. Once the bead is seated and sufficient pressure is in the tire to keep it seated (very little is required) it can then be inflated in a cage.
Once a tire is incorrectly mounted and there is “runout” that tire is on a path to destruction and as was pointed out, dramatic steps have to be taken to true the tire back up. At Michelin, in our training, we spent an entire morning dealing with this issue and seeing how easy it is to mount a tire wrong, not only on the wheel, but mounting the wheel on the vehicle to create runout that feels like a balance issue.
It took zero added effort to mount a tire correctly so everything was concentric, and yet the problem seems to be so widespread between tire dealers that Michelin dedicated an entire morning showing how to do it the wrong way, and then how and why to do it the right way.
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Picture shows the correct mounting position of tire on rim. There is no plan “B”. This ring must line up center correctly done on floor usually laying on a piece of carpet, prior to inflation.
If you inspect your tires …all should be as pictured.
When spin balanced this tire will call for very little balance weightsas it is correctly mounted.
I have watched first spin on tires calling for too much weight. The balance man if he knows his job will deflate the tire and rotate it 180 degrees back on his carpet protector.
Re-installing on balance machine corrects a slightly miss aligned tire on rim, thus no need for large amounts of balance weights.
AL
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The OSHA rule is that a pneumatic truck tire must be inflated within a safety cage or there is isn’t a cage available, then the wheel must be attached to a vehicle, and there cannot be a wall near the vehicle.
Technicians are permitted to inflate air into a tire outside of the safety cage, “only to a pressure sufficient to force the tire bead onto the rim ledge and create an airtight seal with the tire and bead”. The Tire Industry Association, the Technology Maintenance Council, and OSHA have agreed that this amount of pressure sufficient is only 3 to 5 psi. Tests show that the tire is seated against the bead with as little 2 psi, so “3 to 5 psi” is enough.
Here’s the reference:
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Yes, agree with the OSHA rules. I do remember after reading the low air install pre mount is what they normally do.
Didn’t go into great detail but your explanation is correct.
AL
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Is it true that once a new tire has been improperly mounted then driven for a few hundred miles where it heats up then cools, it now has memory and is difficult if not impossible to recenter on the rim
Chuck
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
I don’t know about memory, but the lack of concentricity when mounting causes uneven tire wear so one side the tire may have more tread than the area 180 degrees from that point.
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I have also experienced this issue at times on the road . Then there are roads smooth as can be . I have 1 yr old Michelin’s and in June had a new front end rebuild and alignment done at Prevost in Jack . So I feel the road contributes at times to the feeling of tier issues. We just finished our summer run of over 7k miles with the above results . However still worth looking into and thanks for the detailed info . Good stuff for sure .
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Here is the info on the Tru-Balance nuts JoSam’s put on my 365 steer & tags then they shaved the tires to get them round again. Been about 300 miles and ride is much better.
The passengers side tag was high on the outside edge all the way around (not just a high spot here and there). Might be my imagination but the coach had a slight lane wonder that has seamed to stop since the tires were trued.
Chuck
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The lack of concentricity that created the problem and ended up requiring the tire to be shaved to make it a true round never needed to happen.
To start with the person mounting a tire on the wheel needs to seat the bead with the wheel and tire laying in a horizontal position, and once the bead is seated just use the ring molded into the rubber of the tire near the bead to verify visually the mounted tire is centered. Those two simple actions virtually eliminate a non centered tire.
The next step isn’t so easy. But if the few minutes it takes per wheel are spent the tire is going to run true. With the wheel mounted, but before it is lowered to the floor or ground, use a dial indicator set on the ground or clamped to a fixed spot on the coach with the point or stylus making contact with the tire. Rotate the tire and wheel assembly and note the runout or deviation from concentricity. I cannot remember the allowable deviation, but for this purpose lets say the maximum allowable runout is 30″. If the runout is greater rotate the wheel to where the greatest deviation is at the top, loosen all the lug nuts and allow gravity to drop the wheel down. You may not even realize the wheel has dropped. Retighten all the lug nuts and remeasure the runout.
At Michelin this process was demonstrated and a tire and wheel assembly that had runout of about 80″ was now well within the allowable deviation from concentricity.
A mismounted new tire would feel like it was out of balance. The obvious way to deal with that would be to balance the tire. That would initially correct the problem, but not for long. It soon would again feel like it was out of balance. The bottom line is the tire was wearing into an egg shape.
With a set of tires costing thousands of dollars it just does not make any sense to have some uneducated person slap a set of tires on the coach without doing it properly and then measuring how well the mounting was done. I have seen old time tire guys dismount a tire, and mount a new one with the wheel still on the truck or bus. It is those bad practices that contribute to damaging thousands of dollars worth of tires. Be vigilant.
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All the stars came together to help PC members understand some things that never change about tires.
Tire busters as their called have caused more problems then we can write about.
Excellent post Jon,
AL
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