Strange tire wear on TAG tires

[CCMH]

So after rubbing my hands around the edges of my tires today just checking for wear differences, I found one. Glad I was checking...

It seems my tag axle tires, both of them by the way, are wearing "roundish" around the edges. Unlike the rest of the tires on the bus. Tires have 8,000 miles on them, and just noticed this. Checked the air and the driver side tag tire had about 85lb's of pressure. Will be watching that tire to be sure, however, the passenger side tire was wearing the same... kinda roundish on the edges.

Is this normal for our buses? All of the other tires are wearing flat and sharp on the edges.

Any experience with this kind of wear would be greatly appreciated. Could this be from suspension issues? Chime in one and all.

So appreciative of this group!

[rahangman]

Sounds like a low pressure event....I keep my right at 100

[treedoc]

Curtis You definitly don't have enough tire pressure. A tire on a car, truck or what ever will do the same thing because of low tire pressure. Rick

[Jon Wehrenberg]

Michelin publishes a chart with the correct pressures for the weight carried by the tires. I strongly disagree with those who are of the opinion different pressures will solve the problem.

http://www.michelintruck.com/micheli...ion-tables.jsp

Assuming you have the proper pressures then I would make certain the tires are balanced and the tag axle is aligned correctly.

A tag axle will eat up a tire faster than any other position on the coach once a tire starts to exhibit an unusual wear pattern. When you have the alignment checked, and the tires balanced I would suggest you move them to the drive axle which tends to correct uneven wear.

[LNDYCHT]

Low air pressure is definitely an issue. If you do a lot of tight corners and maneuvering this will also add to this wear. There is more load on the drive axle, so the coach will tend to pivot on the drive axle making the tag axle tires slide as you turn. Low air pressure lets the tire roll over wearin the outside more rapidly. That is why it is easier to maneuver with the tag raised. I would expect to see some scuffing wear on tag tires.

[Jon Wehrenberg]

Depending on how the coach was ordered it may have the system that automatically dumps tag air in sharp turns.

That is invisible to the driver but as soon as the steering reaches full travel in one direction or the other tag air is exhausted and as soon as the steering centers the air bags for the tag axle are re-inflated. Some coaches (Jim C's, Hector's, Michael's and mine) have "stabilizators" (Prevost's term) which are hydraulic cylinders that come into play to keep the rear from dropping when tag air is dumped using the automatic feature.

I have zero unusual wear on my current coach and none on the previous coach and only raised the tag when negotiating extremely tight roads such as in a campground.

If Curtis wants to verify he has the automatic tag dump system he need only drop the front bumper and look up at the steering arm. It will have a stainless steel piece that acts as a cam to actuate a lever operated microswitch. That switch is what causes the dumping of tag air.

[truk4u]

Curtis,

Jon is dead on, forget suggestions to add air before actually weighing the bus and deciding the correct pressure based on the Michelin chart. Once you have that sorted out, then you can look for other causes assuming your pressure is close.

[gmcbuffalo]

Another article on tire use and wear.
http://www.todaystrucking.com/images...Manual2006.pdf

I had the same problem and everything I could find boiled down to under inflation. I had the bus aligned and it came out ok. so I was left with the underinflation theroy.

I have since replaced the tire and will be watching them.

Greg

[jack14r]

The tags take a beating,I am of the opinion that only enough air pressure by the chart is not enough for all situations,weight shifts when we brake,accelerate,corner or when the grade changes.I have seen tags that are scalloped and I also think that too little air pressure is part of the problem,I never set the air pressure on any tire below 100 PSI and I always use 115 on the steer which is higher than the chart calls for.

[Reagan Sirmons]

Jon, I noticed you use your tag sparringly according to your comment. Talk to me about that. I am inclined to use the tag freely yet I do stop when I am putting it back down. I would appreciate comments on this.
Thank you.
Pres