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Open Roads Forum  >  Tech Issues

 > Trailer wheel alignment measurements

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Snowman9000

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Posted: 11/22/11 01:50pm Link  |  Print  |  Notify Moderator

(Paging JBarca! Paging JBarca!)


I have my new to me Crossoards fiver up on jackstands for replacement of tires, brake and bearing service, etc. I decided to check the alignment. My last trailer I had to put new axles on and align them, so this is not my first experience with this.

Anyway, let's start with the measurements:



The front axle appears to be perfectly aligned and toe'd.

The rear axle is where the complications show up. Measured in isolation, it has zero toe, which is great. Measured to the front axle, the rear right side is forward of the left side, yet the rear right side is toe out when compared to the front axle's right side.

The right side hangers are overall 1/8" closer together than the left side's. That pretty much accounts for the right side rear being forward of the left side rear.

While the rear axle in isolation shows no toe in or out, measuring it for parallel to the front axle does show toe out on the right side. Considering the way the axle is located, right side forward, it seems if anything the right side would be toe in, not toe out, when compared to the front.

I could go on, but these numbers don't seem to be adding up. I've already gone back and re-measured. The axles are hanging freely, and the equalizers and shackles are sitting the same on each side.

These are basically new axles btw. Crossroads had an axle problem in 2004 models, and many were replaced. These axles were built in 2005 and still have the remnants of shipping labels on them. So they must have been done under that service campaign. This trailer sat parked at a seasonal site, and all the running gear looks like new. What I'm saying is that it is doubtful that these axles have taken any abuse. That doesn't mean they were made straight, of course.
:/

Basically, what do you see in the numbers? Is it time to get the rear one bent by a shop?

EDIT: I found my errors. See the post after next.

* This post was edited 11/22/11 03:34pm by Snowman9000 *


2014 Sunseeker 2300 Class C (Chevy 4500)


DavidP

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Posted: 11/22/11 02:12pm Link  |  Print  |  Notify Moderator

The most important axle is the front which is perfect, the rear basically just follows and can be off to some degree. The big question is how are the tires wearing? That will tell you what needs to be done. IMO opinion the numbers look perfect and nothing needs to be done. Are you having a tire wear issue?

Snowman9000

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Posted: 11/22/11 03:33pm Link  |  Print  |  Notify Moderator

I don't know. The previous tires just sat. They were old and had to go. I figured I'd check it out before I put any miles on the new tires.

I went back and found my mistakes.
The front axle has 3/32" toe in (measured across a 24" spread from center).
The rear axle has 5/16" toe out.

Those are beyond the allowances. I think I will have them straightened at a shop. I'm going to wait till I get the tires back on and the weight on them to see if anything changes on the toe measurements. It shouldn't, I don't think.

If I absolutely knew I would get straight axles by ordering new ones, I'd do it myself. But these are basically new with very few miles on them, and look how they are. Better to get them bent, I think.

JBarca

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Posted: 11/22/11 07:29pm Link  |  Print  |  Notify Moderator

Hi Snow,

So that I can understand better how you took the measurements, need a diagram on where you put the tape measure with your final measurements.

And was the axle to the frame the same at all 4 wheel locations? Meaning this dimension.


And is the equalizer parallel to the frame? In my case I made sure the camper was level to my level concrete pad and then I could use a level. However you can measure the equalizer to the frame when taking measurements is what I was stating.

When you measure toe at the wheel (drum) and you said you did over 24 inches, how did you do that? Is it like this?






Some thoughts:

If your front axle to the rear axle are out of parallel but your hanger spring pin centers are dead on, then odds and may be when they tightened up the U bolts they may have pushed all the play in the axle seat to the spring pilot pin against each other. Mine, new, had 1/8" play in the axle seat. So I could of pushed one axle full forward and cocked on an angle and then do the other axle opposite. That total play can create 1/4" difference in axle center to center.

Also, before you go nuts on the thrust angle and axle parallelism measurements are the cheap plastic spring bushings shot?

While there are things you can do to adjust thrust angle and axle to axle parallelism, your stuck with the toe the way the axle was made or is now. They either need to be replaced or bent aligned to put them back in.

I'll also ask are the axles installed right? Someone may have goofed and mounted them 180 degrees out. This could turn heavy toe out into heavy toe in. I found on mine the break wire hole in the axle tube should be to the back of the axle to create the right relationship. I do not know if all axles brands are made that way as I did not trust Alko to do it right so I measured at the drums and made sure the front of the axle was installed front.

This much I will say if you are going down the bend to align route, Rebuild the spring pins and shackles with bronze bushed and heavy duty shackles "before" you take it in to bend align. Having them align to worn bushings is not good. Having them optimize the alignment on known bushings is best.

There is one good thing about the bend to align, they can tweak each wheel location under camper load. If you have a heavy slide one side of the camper is heavier generally. The spring on that side can/may flatten more and it can shift the exact numbers of thrust angle and axle to axle parallelism. And that shift can kick a wheel into or out of true alignment under load. How much depends on how out of balance the left and right side of the camper is.

Hope this helps and good luck. Your good work on the Jayco has prepped you well.

John

PS. I myself am not a bend to align fan for me especially if you are grossly out, however I have no major objection for others not wanting to deal with the cost/time of replacing the axles and go the bend to align route.


John & Cindy

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Snowman9000

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Posted: 11/23/11 05:39am Link  |  Print  |  Notify Moderator

Yes, my measuring methods were exactly as shown in your post above. I checked the axle to frame distance and equalizer level too. I used a 24" straight edge at the drums.

I'm with you on the HD shackles. I am planning to order a wet bolt kit today. And a rubber-damped equalizer, if I can find one that fits without lowering the trailer. I understand that's an issue when replacing Al-Ko, which I have, with Dexter. I will say that the running gear shows no wear right now, though. The seller said it was parked at a seasonal site every year.

As for choosing to have them bent, my problem is that it appears to be a crapshoot to get new axles which are made straight to begin with!


JBarca

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Posted: 11/23/11 05:47am Link  |  Print  |  Notify Moderator

Snowman9000 wrote:



As for choosing to have them bent, my problem is that it appears to be a crapshoot to get new axles which are made straight to begin with!


A suggestion, Order Dexters if you are going to order them.

DavidP

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Posted: 11/23/11 08:39am Link  |  Print  |  Notify Moderator

Based on your current measurements before doing anything I would see how the tires wear. I would not be surprised at all if you find nothing needs to be done and your setup is fine.

Snowman9000

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Posted: 11/23/11 11:01am Link  |  Print  |  Notify Moderator

David, it might be acceptable, but it's outside of specs by a fair amount. I have it jacked up and it would not be too hard to fix, if a new axle will fix it.

I called some truck suspension shops that list RV work in their listings. The bottom line is that I'd be better off putting a new axle on. I need to go recheck the specs, but I think the front axle is okay. It is toed-in 3/32" on the 24" spread, which isn't much at all. The back axle is not okay.

Then while I'm at it I might as well address the 1/8" discrepancy in the hanger locations. And do the Lippert enhancement to stiffen the hanger areas of the frame. And Equa-Flex equalizers and wet bolts. I plan to tow this trailer a lot and it will be nice to have it upgraded to suit.

SCClockDr

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Posted: 11/23/11 05:03pm Link  |  Print  |  Notify Moderator

To verify the 2 axles are indeed parallel I use a set of trammel points fixed to a 1" square aluminum bar. positing the points to the center pips of the spindles on the left then check the right. The right pips should accept the trammel points perfectly. If not then there is a parallelism issue.


George & Cathy
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Snowman9000

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Posted: 11/26/11 11:52am Link  |  Print  |  Notify Moderator

I realized I made a novice mistake. I measured the toe in/out on the axles when they were hanging all the way down. That has them rolled back and forward, so the camber comes into play. Today I put the trailer back down onto the tires and rechecked the numbers.

Bottom line, the axles seem fine but the rear one's alignment is off because the hangers are improperly spaced on one side. I am going to tow it over to the Lippert Service Center in Goshen, IN and have them fix it, put on their Equa-Flex equalizers and wet bolts, and do their retrofit crossmembers to strengthen the frame.

It's a hassle but I bet they knock it out in a couple of hours, versus a couple of weeks and a lot of running around for me.


* This post was edited 11/26/11 07:01pm by Snowman9000 *

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