Weird tire wear

[brulaz]

We've put a lot of miles on the new Elkmont recently (across the continent and back), and I just noticed that one of the tires (Marathon 15", passenger/door side) has uniformly high wear on the outside corner of the tread. The rest of the tread and inside corner is fine. The other tire is fine. The pressure is fine (50psi) and always has been (I check frequently).

There's no place inside the wheel well showing signs of rubbing. Clearances seem fine. The trailer's GAWR is not exceeded, and I would expect more of the weight on the other side anyway, with the dual batteries and water tank.

It's not sidewall wear as you might expect from rubbing against the curb, and it's very uniform, so I wouldn't think the wheel balance would be off. Last time I checked, there were balance weights on the back of the wheels.

Since I just noticed it, could this be something recent? Maybe something got stuck in the wheel well?

Or is there some other possibility?

[brulaz]

Took another look and compared tread depths of the two tires. The one with the high corner wear also has quite a bit more wear across the tread.

So now I think I'm wrong about side to side weight distribution. Maybe the passenger/door side does have more weight, from all the kitchen cupboards, frig, sun shade, water heater and water pressure tank. The other side has the main water tank (and batteries), but we usually drain all the water from it before traveling.

Although I like the softer/quieter ride at 50psi, I'll try raising the heavy (?) side tire to 65psi to preserve the tire.

Would like to weigh each side but don't know where I can get that done. The CAT scales I've been using will not work ...

[Keith Wire]

Brulaz,

Would like to weigh each side but don't know where I can get that done. The CAT scales I've been using will not work ...

I see you are in Canada. Are you in a big city or a town where there is a grain elevator? We are in a small town and, although I haven't done it yet, I talked to the fellows at the elevator and they said "sure bring it over"...

Also, when I read your first message I wondered if it was possible that the axle wasn't welded to the frame straight? Have you measured from the tongue to the axle on both sides?

Keith

[brulaz]

Well, we just passed all sorts of grain elevators (in both Canada and the US) on our trip, but I didn't notice this problem until one day from home in Ontario. Even the scale at our local municipal dump station is a full axle scale with no way to put just one wheel on it. I'll keep looking though ...

About the axle and frame (J&B also mentioned this), I'll check when we get back. But I would expect to also be getting odd wear on the other tire if something was not true there. But it's in very good shape.

[wmtire]

Hmmm Bruce, it does sound like something is wrong, maybe with the camber, on that side. There may be a possibility of something being bent there, since it is on the outside.

Just a side note, do you use a weight distribution hitch?

[brulaz]

Yes, we do have a WDH with 800# spring bars. Last time I checked, it was moving 200# off the hitch to the rear axle.

I also just checked the distance from the frame to ground at the tire. The side with the worn tire is roughly 1" lower than the other. I'll check it again after we unload the trailer tomorrow.

[Mr. Adventure]

The Cat scale I recently weighed at had plenty of pavement on one side, so getting weights on one side would have worked great. So I guess they're not all the same.

Does the trailer seem to tow in a straight line?

[RogerR]

Have you considered having the tires re-balanced and inspected by a reliable tire shop?

While you are doing that you might as well rotate them to even out the wear.

[Wavery]

It is normal for trailer tires to wear more on the curb side of the trailer.

Highways are sloped for water run-off. Trailers mostly tow in the right lane which would leave the right side tire down-hill, taking more weight and more drag (as the TV tries to tow the trailer "up-hill").

Trailers and other vehicles with 4-wheels will show ~less of this because they "Track" better on the slope. A single axle (2 wheel) trailer will constantly gravitate towards the low side.

As stated by the previous poster, rotate the tires.

[brulaz]

OK. I'll keep a look out for cat scales where I can just measure one wheel at a time.

I went back and checked the tread wear difference; it's only 1 mm diff in the centre. And measured more accurately the distance difference from axle to frame: 1.5cm. These #'s don't seem too bad after all.

Also checked the axle's relationship to the frame and it seems pretty true, as best I could tell +- 1 cm.

Wayne's remarks sound about right. At least I hope the wear is "normal" after about 15,000 km. I also noticed that a lot poorly maintained highways have some pretty deep ruts on the right side of the right lane which would help explain the edge wear.

So I'll rotate, and probably up the pressure to 65psi on both. That will mean a lot more banging in trailer, but hopefully might extend the tire life.

These Marathons are doing pretty well otherwise.

[Wavery]

OK. I'll keep a look out for cat scales where I can just measure one wheel at a time.

I went back and checked the tread wear difference; it's only 1 mm diff in the centre. And measured more accurately the distance difference from axle to frame: 1.5cm. These #'s don't seem too bad after all.

Also checked the axle's relationship to the frame and it seems pretty true, as best I could tell +- 1 cm.

Wayne's remarks sound about right. At least I hope the wear is "normal" after about 15,000 km. I also noticed that a lot poorly maintained highways have some pretty deep ruts on the right side of the right lane which would help explain the edge wear.

So I'll rotate, and probably up the pressure to 65psi on both. That will mean a lot more banging in trailer, but hopefully might extend the tire life.

These Marathons are doing pretty well otherwise.

Weighing side-to-side may give you some good info for load balancing but will not explain the wear that you have. Even if one side were 200# heavier than the other, the wear should still be even across the tread of each tire (if towed on a level surface). However, one tire may be slightly more worn than the other, over a lot of miles.

If you were towing on level surfaces (which no one does) and had that type of wear pattern over the short haul, I would be looking at a "toe-in" condition on the side of the wear. Even then, the other side would show some evidence of outside wear on a single axle trailer because the other side would compensate to off-set the drag or the trailer would go down the highway noticeably crooked and sway may be an issue.

If you had "Cupping", that would tell you that it is an axle or balance issue. However, you stated that the wear is even. That's a "Drag" and/or under-inflation issue.

[Bill]

It is normal for trailer tires to wear more on the curb side of the trailer.

Highways are sloped for water run-off. Trailers mostly tow in the right lane which would leave the right side tire down-hill, taking more weight and more drag (as the TV tries to tow the trailer "up-hill").Wayne, I'm not sure this is right - is there a source? If I am doing the calculations right, a 2 percent sideslope (about 1 degree, typical* for an Interstate highway) should shift at most a couple pounds from the uphill tire onto the downhill tire. That certainly doesn't account for what the OP is seeing. I think he needs to keep looking.

Or is my math off?

Bill

*Ref: Highway Design Manual, Texas DOT

[Wavery]

Wayne, I'm not sure this is right - is there a source? If I am doing the calculations right, a 2 percent sideslope (about 1 degree, typical* for an Interstate highway) should shift at most a couple pounds from the uphill tire onto the downhill tire. That certainly doesn't account for what the OP is seeing.

Or is my math off?

Bill

*Ref: Highway Design Manual, Texas DOT

It has nothing to do with weight. It has to do with gravity pulling the trailer to the downhill side of the highway. If one were to look at a single axle trailer from the air as it is being pulled down the highway, one would see that the rear of the trailer is pointing slightly downhill from the rest of the rig (depending on the slope of the road). This will cause the downhill tire to have drag on the outer edge of the tire. This would be especially exaggerated if that tire were not at max air pressure.

Most of us would not notice this because we seldom put 9K miles of cross-country driving on our trailers in a short period of time.

We had a U Haul franchise at the dealership group that I managed (years ago). We used to see this on long-haul rental trailers all the time. We probably replaced right side tires 2 to 1 to left side tires.

[ShrimpBurrito]

This will cause the downhill tire to have drag on the outer edge of the tire.

If that happens, then wouldn't the opposite tire drag on the inside, and thus show more wear there, roughly equal to the wear on the outside of the curb-side tire?

Dave

[Wavery]

If that happens, then wouldn't the opposite tire drag on the inside, and thus show more wear there, roughly equal to the wear on the outside of the curb-side tire?

Dave
If you have ever watched race cars racing on a flat, oval track, you will notice that the outer tire is the one throwing up all the dirt. One could use the same logic.....Why doesn't the inner tire throw up as much dirt? The outer tire is the one that takes the brunt of the force of gravity and centrifugal force. The inner tire is just along for the ride.

The principal is similar on a single axle trailer. The downhill wheel (in this case) is the one that absorbs most (not all) of those forces.

I think that you will also find that highways that are built across the plains and deserts are sloped more drastically than the highways around the cities.

[Bill]

Brulaz -

Have you been whipping your TM around a dirt race track on the weekends?? Bad boy! No wonder you have strange tire wear.:D
-------------------------

Wayne -

I don't mean to be argumentative, but if slanted roadways lead to wear on the right tire, then we would all suffer from this. And I just don't recall a flood of reports - or any, for that matter.

In addition, if slanted roadways cause right side wear, then cars would suffer from it as well. Although they have twice as many tires, they travel 10 times as many miles for most of us. And again, I just don't recall any reports.

If you have ever watched race cars racing on a flat, oval track, you will notice that the outer tire is the one throwing up all the dirt. One could use the same logic.....Why doesn't the inner tire throw up as much dirt? The outer tire is the one that takes the brunt of the force of gravity and centrifugal force. The inner tire is just along for the ride.

The oval track story is fun, but not particularly relevant. Race cars on an oval track do indeed wear the outside (right) tires very quickly. But the reason they do is that the cars run around the oval counterclockwise, at high speeds, in a near-constant left turn. The centrifugal force of the near-constant turn makes the car tend to roll to the right. As the weight comes off the inside tires, the stresses are all borne by the outside tires. (And if the driver pushes it too far, the car actually will roll over.)

By contrast, a TM on a straight road does not experience centrifugal force, so there is no tendency to roll in either direction. And on a highway, the turns are very gentle compared to those experienced by a race car on a track. And the turns that it does make are evenly distributed left vs right, so any wear would be balanced between the sides.

The principal is similar on a single axle trailer. The downhill wheel (in this case) is the one that absorbs most (not all) of those forces.

Again, it is the roll that wears the outside tires, not the fact that the outside tires are the downhill tires. In fact, on most tracks, the right wheels are the uphill wheels, not downhill - but they still wear excessively.

I think that you will also find that highways that are built across the plains and deserts are sloped more drastically than the highways around the cities.Again, my experience says that this is not true, and the Highway Design Manuals suggest that it is not. Do you have a source for the statement?

In the end, the only reason we care is that the Original Poster (OP) is experiencing a problem, and he needs help identifying the cause. I don't think we can just blow it off as the inevitable effect of slanted pavement.

Bill

[mjlaupp]

Brulaz,

A Google search on the net produced this hit at The Hull Truth Boating Forum:

http://www.thehulltruth.com/boating-forum/224101-uneven-tire-wear-trailer.html

The poster reported the same tire wear on the outside of the curb side tires. The diagnosis was bent axles most likely caused by hitting curbs or potholes.
Repair was to replace the axles.

[ED-n-KEL]

Hmmm Bruce, it does sound like something is wrong, maybe with the camber, on that side. There may be a possibility of something being bent there, since it is on the outside.

I'm with WMTIRE here...
I think you need to have the alignment checked.
Just because it's a new trailer, doesn't mean they can't make blunders when manufacturing the axle.

[ED-n-KEL]

We had a U Haul franchise at the dealership group that I managed (years ago). We used to see this on long-haul rental trailers all the time. We probably replaced right side tires 2 to 1 to left side tires.

Wayne's explanation sounds totally feasible to me, but I'd still want to have the alignment checked, if only for peace of mind.

[Kevin Krause]

Bill stole my thunder. I was going to joke about high speed cornering and a preference for left turns. Are you guilty of either of these Brulaz?

[brulaz]

So where do you go to have the alignment checked on a Dexter axle on a travel trailer?

Are there RV dealers competent to do this or ... ?

And no, no race tracks, counter clockwise or other wise

EDIT: John Wahlstein has taken his Elkmont on a similar trip, except his tires were at 65psi.
Hopefully he'll chime in with his tire wear story, or lack of it.

[ShrimpBurrito]

FWIW, I just took some measurements on my tires. I just bought them in Grand Junction, CO in mid-June (~3 months ago) due to blowouts enroute on a transcontinental trip. From there, we traveled to the east coast, and then back home to Los Angeles, driving an additional ~6,000 miles over the course of about 6 weeks. Much of that was interstate, and the TM weighed about 4,100 lbs on that trip. For maybe 2,000 of those miles, tire pressure was 80 psi. That is the max pressure for the tire, at which is has a load capacity of 2830 pounds. Not a good idea....everything in the TM shakes....but I was paranoid about more blowouts. For the rest of the trip, they were 70 psi, and since we've been back, I now run them at 65 psi.

There are 4 tread grooves on each of my tires, and I just measured each one of them on both tires using a tire tread depth gauge. I have no idea what the depth was when I bought them, but I can tell you that every one of the grooves on both tires is 10/32". Thus, both tires appear to be wearing evenly, both across each tire individually as well as in comparison to each other.

I'm not sure if that data is worth anything, but I was curious myself so I thought I'd share.

Dave

[ED-n-KEL]

I would assume almost anyone with an alignment rack should be able to check it.
Go make a dry run to your local tire chain store and simply ask them to see what they say before lugging the TM to them.
An important point here is that they probably won't be able to do anything about correcting it. They will merely either rule it out, or confirm something is bent.

[mjlaupp]

So where do you go to have the alignment checked on a Dexter axle on a travel trailer?...
Try this:
http://www.dexteraxle.com/find_a_distributor

[Wavery]

So where do you go to have the alignment checked on a Dexter axle on a travel trailer?

Are there RV dealers competent to do this or ... ?

And no, no race tracks, counter clockwise or other wise

EDIT: John Wahlstein has taken his Elkmont on a similar trip, except his tires were at 65psi.
Hopefully he'll chime in with his tire wear story, or lack of it.
You can check for toe-in by measuring the distance from the front of one tire to the front of the other tire and compare that to this measurement from the rear of the tires. They should be the same distance.

For camber, you can use a simple carpenters level or dropping a plumb-line next to each tire (on level ground). You could also use a 24" carpenters square (on straight, level ground).

http://t3.gstatic.com/images?q=tbn:ANd9GcR9YXE75PbT_dQEkoNPa6Nh6_mWMX8oD Dgf7YTnmxhmth7Rrqw&t=1&usg=__zyq_bAyDnnBcjCXgV1CtKu3tKKA=

http://t3.gstatic.com/images?q=tbn:ANd9GcTdF7KOYwmIwjtGq57f8hzxf164n6SZY SpnVMyy7PJqSn0mTUA&t=1&usg=__KgVlLRbADuRSxNMI0MnE3lYlOck=

The key is knowing that the surface that the trailer is sitting on is level......

[Mr. Adventure]

So where do you go to have the alignment checked on a Dexter axle on a travel trailer?

Are there RV dealers competent to do this or ... ?

And no, no race tracks, counter clockwise or other wise

EDIT: John Wahlstein has taken his Elkmont on a similar trip, except his tires were at 65psi.
Hopefully he'll chime in with his tire wear story, or lack of it.

I've never looked closely at this before, but is it even possible to adjust the alignment of a trailer axle? These pictures from the Dexter site show pretty solid connections from the spindles all the way to the trailer frame:

http://dexteraxle.com/i/u/1080235/f/6-8K_cat_4-07/2300-3500_lbs.pdf

[rumbleweed]

I don't think an individual wheel can be adjusted, but the entire axle could have slipped out of alignment if a large pot hole was hit with one wheel and the frame clamp was not tight. Probably more prone to this with a lift kit. If this was the case, I would expect uneven wear on the other side of the other tire.

[Bill]

I hate to bring this up, but ... Both TM and Dexter Axle warn owners never to jack up the TM by putting the jack under the axle. Reason? The axle will bend, and may take a permanent set. This would cause wear on the outside of the tire at the bent end. I think this is the "camber" that wmtire mentioned.

Several years ago, as part of my switch to 15" tires, my local tire jockey started to jack up the TM by putting the floor jack under the axle. Fortunately I caught him. The jack must be under the frame.

Brulaz - anything?

Bill

[brulaz]

I always jack it up using the corner leveling jacks. Nothing on the axle. And I bought it new so ...

Can't get at the trailer right now, but next week I'll use a carpenter's level to check for a bent axle, but I'm not sure what that will tell me. Even if bent, the torsion link could be offset so the tire camber is ok.

So will also call around some local tire/alignment shops to see if I can get the camber checked. Can't think of anyplace level enough for me to do it. I know there's one shop that routinely has trailers and rv's in it's lot ...

And if the camber is off, there's no adjustment that I know of except whole axle replacement?

[ShrimpBurrito]

Several years ago, as part of my switch to 15" tires, my local tire jockey started to jack up the TM by putting the floor jack under the axle. Fortunately I caught him.

This same exact thing has happened to me. It's the norm to jack up the axle, so you really need to watch the tech. Even if you tell the guy at the counter, and he writes it on the work order, the tech actually doing the work likely won't follow through unless you are standing over his shoulder.

Dave

[cochise]

Took another look and compared tread depths of the two tires. The one with the high corner wear also has quite a bit more wear across the tread.

So now I think I'm wrong about side to side weight distribution. Maybe the passenger/door side does have more weight, from all the kitchen cupboards, frig, sun shade, water heater and water pressure tank. The other side has the main water tank (and batteries), but we usually drain all the water from it before traveling.

Although I like the softer/quieter ride at 50psi, I'll try raising the heavy (?) side tire to 65psi to preserve the tire.

Would like to weigh each side but don't know where I can get that done. The CAT scales I've been using will not work ...

I wanted to lower the tire pressure to 50 PSI also, to get a smoother ride, but I contacted Goodyear and was told NOT to deviate from the posted 65 PSI as it could affect the tire wear and also void the warranty. So maybe that is your problem.

[cochise]

Brulaz,



I see you are in Canada. Are you in a big city or a town where there is a grain elevator? We are in a small town and, although I haven't done it yet, I talked to the fellows at the elevator and they said "sure bring it over"...

Also, when I read your first message I wondered if it was possible that the axle wasn't welded to the frame straight? Have you measured from the tongue to the axle on both sides?

Keith

The tire/wheel needs to be perpendicular to the road surface. Maybe is it not.

[Wavery]

This same exact thing has happened to me. It's the norm to jack up the axle, so you really need to watch the tech. Even if you tell the guy at the counter, and he writes it on the work order, the tech actually doing the work likely won't follow through unless you are standing over his shoulder.

Dave
That's a fact.......When I took my trailer in for tires, last year, the tech stuck a floor-jack under the axle automatically. I was standing right there so I asked him to please jack up the trailer by the frame, behind the axle. He was happy to comply.

I think that he knew that it was wrong but it is faster and easier to use the axle and they assume that the customer doesn't know the difference.

He also did not torque the lug-nuts. He just spun them on with an impact wrench. When he was finished, I went to my truck, pulled out my torque wrench and torqued them myself. I didn't say a word but the shop supervisor was visibly embarrassed. I think that he was about to tell me that I couldn't do that in the shop but changed his mind. When I went to pay my bill, he gave me a "Courtesy" 10% discount. I thought that was nice.........BTW.......I would go back there again in a heart-beat.

The tire/wheel needs to be perpendicular to the road surface. Maybe is it not.

That's also correct. If the surface is straight (from one side of the trailer to the other), it doesn't need to be perfectly level if you are using a square from the surface to the wheel to check the camber. If you are using a level, the surface must be level from one side of the trailer to the other. It would be nice to find a concrete surface that is both level and straight and check it with a square and a level. After-all, that's all an alignment rack does. The alignment rack is level from one side to the other and each tire pad is square and level.............BTW, I would check both sides and compare the findings.

You could stretch a chalk-line over the grounds surface to see if it is straight (no gaps under the string or the string not hitting high spots). When you find a straight area about 10-12' across, snap the chalk-line and put the tires on the chalk-line.

[brulaz]

Haven't had a chance yet to take it to an alignment place, but did check the axle.

The axle looks bent upwards in the centre. Laid a 65cm strait edge against the bottom centre and there's about a 6mm gap in the centre. But from the centre to the frame it measures straight. The brackets attaching the axle to the frame also seem to be bent slightly inward to compensate? But that's just by eyeball.

The camber/tread wear problem is only on one side though while the axle bend appears to be precisely in the middle. Could the bend be normal, deliberate? Perhaps to compensate for some reverse play at the axle/torsion lever, torsion lever/wheel attachments?

[wmtire]

Could the bend be normal, deliberate?

It's actually for the camber, and this is taken from the FAQ's of dexter website.

AXLES - Why are some axles bent in the middle?
The upward bend in the axle is called "camber". Camber is the angular relationship of the wheel to the road surface in the vertical plane. Axles are typically built with a pre-determined bend in the tube that compensates for the expected deflection under load.

Have you ever noticed an empty flatbed trailer being towed by a semi-truck? You will also notice these trailer beds have an upward bend to compensate for when it's loaded.

[brulaz]

OK. Thanks Bobby.

And despite that really obvious camber in the axle, the tire does seem perpendicular to the ground. I don't have a flat surface anywhere around here so I just leveled the trailer with the jacks, taking as little weight off the wheels as possible. Then put a unwarped 2x6 in front of the tire, leveled that and laid my big carpenter square up against the side of the tire. It was a perfect 90 degrees as best I can tell.

Not sure how accurate that is, but I'll accept it. So I swapped the tire with the spare (new) and set all pressures at 65psi. It will be a while before we put 15,000 km on this one. We'll see what happens. Hopefully the higher pressure will at least reduce this problem.

[brulaz]

Well, much to my surprise, Trailmanor decided to replace the axle, wheels and tires with new stuff. I had the trailer down there for roof repair and asked them to look at the tire wear. They talked to Dexter axle, Ed (of Trailmanor) said nobody could come up with a good explanation, but that something was obviously wrong, so they just replaced it all! They plan to send the axle back to Dexter to see if they can find anything.

Obviously we were pleased. We also got the new style aluminum wheels.