I haven't found anything on this using the search feature, so...

I just noticed that the sidewalls on my BFG AT KOs are distorted, i.e. wavy and bumpy. Checking around I see that this is not unusual for light truck tires, but not found universally either. Mine appear to be the most extreme example but you can only scrutinize so many tires in parking lots.

I just had them rebalanced and rotated and the techs made no comment. They washed them which is how I noticed in the first place. Yes, they have been used hard. I don't rock crawl but I do jeep trails and unmaintained roads. I encounter a lot of washboarding, ruts and potholes on the latter. The tires are are 2-3 years old (not sure).

Has anybody else experienced or seen this and if so, any comments? I want to hear something from this forum before I hear something from a tire saleperson.

I haven't seen that or heard of that before, not on the AT KO's at least. They have a thicker sidewall than all street oriented tires; thus I would not be surprized to see that from a street tire, but not the KO's.

That's a defect. It MAY have been there since you got them.

I haven't had a set do that, but I've seen other tires with it...and while not that unusual in the tire world, its still not normal.

it depends on what the wavy part looks like. if its a round bubble or a finger shapped bubble the its from the tire being pinched against the rim.

if its an indentation then its the seam of the tire. that type of seam is mostly seen on truck and suv tires, but i have seen it on performance and regular tires as well. the indentation is not anything to worry about. it is common.

some may disagree with me and thats fine, its not like i managed a tire shop for years, or have been sent to many classes about tires and construction of tires by major companies such as Goodyear, Michelin, and Continental.

if you said you had goodyear trackers (the original version) i would say take them back right away, because they have a design flaw and is why they are no longer being produced.

It sounded like wavy rather than bubbles from the description...so it is typically from mounting issues as as described, or from plies with uneven tension, so as to produce areas of sidewall with tighter and looser ply sections.

As the tire rolls, the hysteresis impact builds due to the uneven tension, and premature failure, especially at speed, can occur.

For normal/low speed driving, it rarely has an impact.

If its a ply tension defect, it was likely present when purchased, and should be taken back.

from The Tire Rack

"Sidewall Indentations, Undulations and Protrusions

It is not unusual to find subtle indentations in the sidewalls of radial ply tires. Fortunately they are a visual condition that will not affect the performance of the tires.

Sidewall indentations (also referred to as sidewall "undulations") are a common characteristic of tire construction on almost all radial tires. These indentations are more noticeable in larger tires with taller sidewalls, as well as tires that operate at higher inflation pressures.

Tires are reinforced by encasing individual fabric cords (typically polyester or rayon) in rubber. Radial ply tires feature one or more layers of cord (depending on the tire's required strength) that basically run parallel to each other from bead to bead (with each individual cord running up the sidewall, across the tread and down the other sidewall). Because of their "straight across" direction, the overlap where the sidewall cords are lap-spliced may sometimes cause a slight indentation.

When the tire is being cured, it is pressed against its metal mold. However when the tire is mounted on a wheel and inflated to typical air pressures, it is free to naturally expand. These overlapping splices may create slight indentations since the stretching capacity of the lap-splices is slightly less than the rest of the body ply material because the splices are the most reinforced area of the tire's sidewall. Since radial tires feature steel cord reinforcing belts under their treads to keep them flat, indentations only appears on the sidewalls.

However, if protruding bulges, rather than indentations appear on the sidewall of a recently installed tire, it reveals that there is an undesirable gap between some of the body ply cords inside the tire. The tire should be removed from service and replaced under the tire manufacturer's defects in materials and workmanship warranty.

If a protruding bulge doesn't appear until later in the tire's life, it was usually caused by a road hazard when the cord was injured as the tire struck a pothole, curb or object in the road."

Ahh... thanks. Mostly it is the indentations you refer to, and they are somewhat regular. However, there are some bulges which appeared after a couple year's use, and hard use it was at times! I suspect my last trip into Death valey is the culprit: loaded with passengers and gear, miles of washboarded and potholed gravel/dirt road, speed about 25mph. Maybe next tires should be 6-ply.

Just checked out my BFG AT's and they seem to have the same thing you are describing. No issues with them and I just had my emissions test/balance rotate and nothing was said.

BTW:
Thanks Steel for the TireRack Info!!!!

Tim

that info was basically what i had already said, but comming from a reputable business and a sponsor of this site. that way it carries more weight and doesnt sound like it was just my "opinion".

Just for grins I called some local shops and of the five that I called all but one tried to sell me new tires. The one good one was CostCo!!!

Tim

PS- Not sure how to do it but you might want to see about putting this up in the sticky posts at the top just in case others were curious about the same thing.

Like anyone ever reads the stickys.

this is true, but it should be a sticky anyway.

So far, the main purpose of the stickies is to make it easier where to tell the newbies to look for the answer to their post....rather than answering their post.



The differing tensions I described, and that TireRack described are the same I think...the difference is they sell tires, and they don't want too many returns for flaws...and I've seen the one's with this issue get worse with time and fail eventually...sometimes.

So people who SELL tires will call it "normal", and people who DRIVE on the tires can consider it a defect.

(A defect doesn't mean the tire won't work, just that its made with uneven tensions, which over time, get worse...if you wear out the tread/replace the tire under normal wear and tear first, you win...if not, you lose/get a PRO-Rated compensation of a few bucks to represent the loss in use, etc.)

I worked with people who MAKE the tires for example, and the difference in emphasis between those who SELL the tires, and those who MAKE the tires, is my perspective.

The MAKERS TELL the Sellers the TireRack type blurb, the seller's believe it, and tell the customers...who therefore accept the tires in good faith, and, often, w/o any problem what so ever....making the system work.

We have a post above from one customer who noticed the deterioration over time though as an example of what I'm talking about....soup to nuts.

Its a Fox and Hen House question.

yeah your right, as usual. sorry i ever said anything. :rolleyes:

Sheesh, I'm not saying you are wrong...most of the time its true, which is why the system works most of the time...its the rest of the time that I'm trying to caveat.



Sorry if it sounded like that.

Lets say I wanted to clarify the issue, not dispute it.

developing a "conspiracy theory" between tire manuacturers and tire sellers, is a long way to go to "clarify" something isnt it?

the info i posted from tire rack was out of speed, i didnt want to take my time to find a similar artical published by "Michelin" a "tire manufacturer", discussing the same subject matter, which is where i got my original info from in the first place. ie. attending classes that they (Michelin)sent me to.

Aww, its no more a conspiracy theory than any other customer service algorythm.

Most makers of things have to deal with returns, and they issue guidelines to try to control their losses.

As we all seem to agree that the tires in question (mostly) last long enough to be OK with the consumers, the algorythm works, and the sellers prevent (excess) returns for the defect....as if they took ALL of them back, they might go under in a short time, etc....and only a small number really needed to be taken back anyway.



If you buy something, and you bring it back because it seems to have a flaw, say the new car makes a particular noise when braking...nine times out of ten, you will be told something to the effect of "That's normal, they all do that, don't worry about it".

This is how most business stay in business...because the odds are in their favor.

Now, if the flaw is hazardous/has a higher known failure rate, they don't do it, as they are then exposed to tort liability issues they'd rather also avoid...so - they only do this when the flaw is not likely (Enough) to lead to failure.

And I'm not only talking about tires...its a general business practice.

Didn't know this was news to some.

Chances are that there is not a problem if experienced tire techs think they're OK. If you think your shop is giving you a false opinion, get a second opinion from a "neutral" shop. The most important thing is not to take any speculative answers from internet people who have never seen the tires in question. I have seen many different types of undulations in tire sidewall and only certain types constitute a defect. SteelX seems to be very knowledgeable on this subject and I tend to agree, in general, with his viewpoint.

Good luck. Let us know what the results are.

Well, thanks all, for the research and discussion. I did get the chance to check out another set of identical tires on a Jeep, fairly new, and noticed the same thing. This seems to jibe with most of what I heard elsewhere, i.e. it appears to be common with this make and model. The tread wear is even and the tires behave on the road after balancing. At least I can be easy in my mind when I next go out. However, I wouldn't mind going for heavier construction (more plys) on my next tire replacement. Too bad there's not a heavier version of the AT. The MTs are not what i want as far as tread goes.