Axle mounted wrong?

[Roadtoaster]

Is this even possible? I've consistently had a wear problem on the curb side rear tire, even after having an alignment done at JC. Here are the symptoms;

1. Curb side rear tire wearing on inner and outer edges
2. The distance between the two curb side tires is greater than the distance between the street side tires.
3. The trailer tracks slightly off center, pulling to the curb side
4. The rear tire on the curb side is closer to the back wheel well opening than the street side

I've not hit any curbs and no other major impacts to the tires. Is there any adjustment in the axle mounting or do I have a frame mounting hole problem?

Any insight appreciated.

[Inland RV Center, In]

Originally Posted by Roadtoaster

Is this even possible? I've consistently had a wear problem on the curb side rear tire, even after having an alignment done at JC. Here are the symptoms;

1. Curb side rear tire wearing on inner and outer edges
2. The distance between the two curb side tires is greater than the distance between the street side tires.
3. The trailer tracks slightly off center, pulling to the curb side
4. The rear tire on the curb side is closer to the back wheel well opening than the street side

I've not hit any curbs and no other major impacts to the tires. Is there any adjustment in the axle mounting or do I have a frame mounting hole problem?

Any insight appreciated.

How about some photo's?

Are the tires exactly the same?

Measure from the back side center of the jack post back the the lowest forward edge of the axle mounting plate, which is the plate welded to the side of the frame. That dimension should be exactly the same for each side.

The measure the distance between the front and back axle mounting brackets.

Post that information and I will try to help you.

Andy

[HowieE]

Make sure the tires are the same diameter. Marathons will grow in diameter just before they blow.

While it is hard to believe the factor drilled the frame wrong I would get under there and make some measurements side to side between the front and rear bolts on the axle sets.

If the above checks out within reason.

These axles are not aligned will when they are made. It is the nature of the beast.

Take a straight edge, I use an 8 ft. florescent light bulb, and lay it across the center line of the wheels. All four edges of the tire should hit the tube or no more than a 1/16 off. If you have miss alignment they can be straightened, but for Gods sake do not take them the a Dealer or Jackson for that work. Find a truck axle shop, Gaumers in Chambersberg Pa. is where I go and have them aligned. Alignment requires some real equipment and some real know how because the axle tubes themselves have to be bent and this is a cause and effect situation.

[Roadtoaster]

Tires are new 16" Michelin's, zero miles, all the same size, all inflated to 70 lbs. I will get some photos and measurements posted later today. On edit, I also did the straight edge comparison, all in tolerance.

[Roadtoaster]

Not sure I measured to the place you said but I did measure to the same point on both sides of both axles. Bottom line, both curb side axles are mounted 1/4 inch farther back than the street side. Considering the wear on the rear tire, I must have a severe alignment problem otherwise the front curb side tire would be wearing too, wouldn't it? Also consider that deflection of the tape measure over almost 15 feet could account for some or all of the difference in measurements. Thoughts?

[nickmeloy]

Originally Posted by Roadtoaster

Not sure I measured to the place you said but I did measure to the same point on both sides of both axles. Bottom line, both curb side axles are mounted 1/4 inch farther back than the street side. Considering the wear on the rear tire, I must have a severe alignment problem otherwise the front curb side tire would be wearing too, wouldn't it? Also consider that deflection of the tape measure over almost 15 feet could account for some or all of the difference in measurements. Thoughts?

Is the picture in this post an indication of possible under-inflation for the load being imposed on the tire?

[Inland RV Center, In]

Originally Posted by Roadtoaster

Not sure I measured to the place you said but I did measure to the same point on both sides of both axles. Bottom line, both curb side axles are mounted 1/4 inch farther back than the street side. Considering the wear on the rear tire, I must have a severe alignment problem otherwise the front curb side tire would be wearing too, wouldn't it? Also consider that deflection of the tape measure over almost 15 feet could account for some or all of the difference in measurements. Thoughts?

Measure again and again.

Each 1/8 inch side to side difference in the axle mounting plate, will cause both axles to be out of alignment with respect to the shell, and result in about 3 inches dog legged towing, from front to back, per 1/8 inch, for a 31 foot trailer.

Andy

[Roadtoaster]

It certainly could indicate that but I have a TPMS and check pressures constantly, adding air to maintain 65 psi. This same tire location was the one wearing before I had the alignment at JC.

[overlander63]

Originally Posted by Roadtoaster

It certainly could indicate that but I have a TPMS and check pressures constantly, adding air to maintain 65 psi. This same tire location was the one wearing before I had the alignment at JC.

The last Marathon on our trailer that disassembled itself showed wear like that.
Generally, if the alignment is off, either the inside tread or outside tread will be worn, not both. If toe is really bad, the entire tread will be worn off, usually more on inside or outside, and the remaining tread will be excessively feathered.

[nickmeloy]

Originally Posted by Roadtoaster

It certainly could indicate that but I have a TPMS and check pressures constantly, adding air to maintain 65 psi. This same tire location was the one wearing before I had the alignment at JC.

I did not mean to infer that you were running the tire pressure low. What I was trying to suggest was that the actual loading on the tire was such that 65 psig was insufficient to support that load.

[panheaddale]

That doesn't look like an alignment issue. Wear is to consistent on both sides of the tire. Definitely looks like an underinflated tire. What is in the trailer over top of that tire? Looks like there might be a lot of weight over that tire to where it may need more than 65 psi to wear correctly. No center tire wear is kinda the give away for underinflation.

[Roadtoaster]

Over that tire is the closet and part of the shower, certainly no extra weight as you might find with a fridge. I believe the black and fresh water tanks are on either side of that axle. Never full when driving. I'd hate to think I'm the reason for the condition of that tire!

[Roadtoaster]

Originally Posted by Inland RV Center, In

Measure again and again.

Each 1/8 inch side to side difference in the axle mounting plate, will cause both axles to be out of alignment with respect to the shell, and result in about 3 inches dog legged towing, from front to back, per 1/8 inch, for a 31 foot trailer.

Andy

Thanks Andy. I had to take the trailer back to the storage lot so I will measure again next weekend. Interesting how a fraction of a inch can significantly affect off center towing.

I appreciate everyone's comments. With new Michelin's on the trailer, I would like to fix this issue.

[cwf]

Another "possibility" might be that that other axle on that side is not holding up enough weight. That woul overload that specific tire.

Check ride height and level tow or slightly elevated at tongue. The higher the tongue the more weight shifts to rear axle. Yet, if rear axle cannot support the load, the front must.

I do not recall how to verify you have correct and matching axles, but I would start with those basic checks. It is possible the carry capacity on the side wearing is reduced on the non wearing or, there is a problem with the failing tire support where it is not moving enough.

[xrvr]

Bad wheel? Hub? Lug nuts loose? Jim

[M2HB]

If it was me, I would put it on a concrete surface with a creeper so I could take a good look at it. I would run a string from the center of the coupler (spaced down to clear) to the center of the rear bumper. I would then use this centerline (trig) to determine if the axles are perpendicular to the centerline. Also, don't just measure to the mounting plates. I have seen mounting plates that weren't made correctly and the axle wasn't positioned in the mounting plate as it should have been. The part that matters is the spindles being perpendicular to the centerline of the trailer and the proper bow in the axle to compensate for the weight that will be applied to that axle. You can measure from the back of the frame (or another known point), but you are assuming that the frame was built correctly when you do that.

[Roadtoaster]

Hopefully I will have the time this weekend to continue the investigation. I have a long trip starting in about 6 weeks so no time to waste. I do appreciate everyone's suggestions.

[LFC]

Originally Posted by Roadtoaster

2. The distance between the two curb side tires is greater than the distance between the street side tires.

4. The rear tire on the curb side is closer to the back wheel well opening than the street side

Check the wheel well openings when you pulled straight forward....when backed up to park the wheels can appear to be out of line with the wheel well openings.

I was told it's because the axles are torsion bar axles and they flex and twist when you back up.