Tandem Axle Alignment

J

jhspear

New member
The trailer for my 2008 C-Dory probably had less than 2 thousand miles on it and yet the tires were clearly worn (plus old). I had them replaced with Goodyear radials at a reputable shop I frequent and on their advice I took the trailer to a specialty shop to have it aligned. The front axle aligned perfectly but the rear axle was bent such that the total toe in was a negative 1 1/4 inches and camber was a positive 3/4 inches. I was told that the axle was actually bent near where the torsion bars were connected and thus could not be aligned and had to be replaced.
EZ Loader had a new axle shipped up from Indiana to Wisconsin in a day and I will have it installed Friday. No...it was NOT free....I now know that axles are plenty expensive.
The shop foreman explained that he sees this problem frequently with trailers as axles are made with no regard as to the specific purpose as different trailer frames and loads result in various alignments which may or not be acceptable. He recommended having the axles of new trailers aligned. I forgot to ask, but assume that this would be particularly critical for tandem axle trailers.
Having seen other postings with complaints about rapid tire wear, I suspect trailer alignment might be a factor. One other interesting point the foreman made was that a slight positive camber as opposed to a negative camber will result in greater resistance to the wheel being knocked out of alignment when a curb or other obstruction is hit.
Anyone have a take on this?
 
Good god, it was out inches???? Most of the time rapid tire wear is from the boat being too heavy for the trailer. I didn't know you could even align a tandem trailer. Sounds like whatever caused the axle to bend was a heck of a bump.
 
There was a 26 trailer which had tires blow out, wheels destroyed, and axle bent, just from going over a curb or some one of those low barriers.

In our experience we had some bad tire wear with bias tires, and probably the trailer not being perfectly level. Going to radials, and using an adjustable hitch/equalizer hitch, resolved wear issues….So there are a number of things which can cause the wear.
 
Recently, I went through an event with my dealer concerning the new aluminum
tandem trailer, placement of the boat (CD 26 Venture), tongue weight
adjustment and axle positioning ("alignment" not mentioned but assumed -
maybe my error).

Apparently, to get close to the correct placement of the boat on the trailer, it
first should be loaded; minimum is fully fueled and watered - more gear is
probably better here. It is then placed on the trailer, fore and aft, to achieve a
tongue weight of 5 - 8 %; mine was a bit over 500 lbs which was in the range
and also be properly on the bunks.

Then both axles were moved forward on the trailer frame about a foot to
achieve the right balance. Not sure how this was calculated. "Experience" I
remember being thrown around.

My grand assumption, the axle alignment, was not mentioned but will be
measured today and thought of on future road trips by looking at tire wear
and observing handling on the road.

Towing the trailer level is another important factor. My Venture trailer is
stamped with "Hitch at 22" - a consideration in hitch selection. This trailer Mfg
states in the Owners Manual that a WEIGHT DISTRIBUTING HITCH SHOULD NOT
BE USED as it interferes with the trailer surge brakes. I am fortunate my tow
vehicle has automatic air suspension leveling to assist in towing.

My trailer/boat numbers:
a. Trailer + boat (100 gal fuel + 25 gal water): 8350 lbs (per dealer)
b. Trailer GVWR: 9365 lbs (on trailer plate)
c. Trailer maximum capacity: 8025 lbs (on trailer plate)
d. Trailer weight: b. - c. = 1340 lbs
e. Boat weight: a. - d. = 7010 lbs
f. Trailer/boat tongue weight: 550 lbs

Aye.
 
Foggy":rne2fb85 said:
Apparently, to get close to the correct placement of the boat on the trailer, it first should be loaded; minimum is fully fueled and watered - more gear is probably better here. It is then placed on the trailer, fore and aft, to achieve a tongue weight of 5 - 8 %; mine was a bit over 500 lbs which was in the range and also be properly on the bunks.

Then both axles were moved forward on the trailer frame about a foot to
achieve the right balance. Not sure how this was calculated. "Experience" I
remember being thrown around.
Click to expand...

The only part about this that confuses me is why they would move the axles forward a foot after they had the "just right" 5-8% tongue weight. That seems like it would throw things way off. I moved mine a few *inches* and it made a big difference in the percentage of tongue weight. Maybe they moved it a foot first, in order to achieve the proper tongue weight, but it just sounded backwards as I read it?

As far as loading up before getting the balance right: I tend to tow the boat with its fuel and water tanks empty, so I set mine up that way. Not that it throws things completely off when they are full - it's still fine - but empty is more common for me (I'm sure others are different that way). My tongue weight is at just 8% now (thank you Oregon, for all your free public scales that make it so easy to keep tabs on things) with tanks empty, and full tanks would add most of the weight behind the axle, so that probably helps in the flexibility.

From what I understand there are now weight distributing hitches that can be used with surge brakes, but perhaps your trailer manufacturer (still) advises against them for a specific reason. I haven't used them/don't need one with my 22, but have just read reviews, etc. I thought I might need one with my newer tow rig (to take weight off the rear axle), but it ended up being fine, and even with capacity to spare, without anything added.

I've been surprised with both my tow vehicles in that I expected them to "sag" a bit when I hitched up, so I planned for that when setting the ball height, but... they didn't really move. So I had to go back and re-adjust my hitch ball height. There is no number stamped on my trailer, but I used a level on the frame to check it. Top of the ball 19-1/2" off the ground in my case makes the trailer flat/level.

Sounds like you are getting close to taking delivery of your new C-Dory. Exciting times!

***
On the topic of axle alignment: I'm going to have to take another look at my trailer today. The axles are attached to a sort of "carriage" that includes (I thought) the axles, fenders, and springs. Now I'm curious if that aligns the axles, or if they are set separately. My tire wear has been even, but I just want to see how it works now.
 
I still don't really see how you could do any meaningful kind of alignment on any of the boat trailers I have worked on - which is a lot of them. Sure you could angle the axle quite a bit from left to right, but then you'd have positive toe on one side and negative on the other. Adjusting camber? How? The spindles are welded/bolted onto the axle tube. I guess you could put the axle in a jig, apply heat, and then use a puller - never heard of it, but possible. I guess you could adjust caster by sliding the axle forward, but I'm not really sure that counts as the centerline of the axle is the same. And the rest of it, it is all just bolted together.

There are kits I have heard about and seen in catalogs that allow adjustments, but I have never worked with them and haven't heard of them coming from manufactures with them installed. When I worked at a local RV parts store, every once in a while someone would inquire about them and they were expensive. The service department never used them and I don't remember every actually ordering one. For the most part, if something was bent and showed an out of alignment condition, you just started replacing hangers, hardware, axles, and anthing else that wasn't plumb. Of course, this was a long time ago and things probably have changed since then......somebody knows....I'm interested.
 
I am in the process of rehabing my EZ Loader trailer, (for a C-22).
I have experienced tread wear on the outside of the rear right tire, its a
tandem. I have talked to several alignment shops and they have had nothing to offer. The spindles on that right side are apart 3/16 different from the left side. the axles are bolted in place and offer no way to adjust them. My conclusions that the axle is bent. A replacement is $600 plus shipping. The wearing is rather slow and $700 will pay for a lot of tires. I'll be keeping an eye on it.

Carpy
 
When I had my single axle trailer upgraded to tandem, the shop replaced the old single carriages with doubles. On these carriages, if the distance between the pivot holes is the same on right and left side (as they should be), and the pivot shackles are the same length (as they should be), then the axles will be parallel. By measuring from the hitch to each side carriage, and sliding these carriages forward or back, the tongue weight and perpendicular alignment can be achieved. Once this is correct, unusual tire wear can only be caused by bent or weak axles.

The shop did a great job on my trailer. Tire wear is normal.
 
bcassal":do3c0h4r said:
I am in the process of rehabing my EZ Loader trailer, (for a C-22).
I have experienced tread wear on the outside of the rear right tire, its a
tandem. I have talked to several alignment shops and they have had nothing to offer. The spindles on that right side are apart 3/16 different from the left side. the axles are bolted in place and offer no way to adjust them. My conclusions that the axle is bent. A replacement is $600 plus shipping. The wearing is rather slow and $700 will pay for a lot of tires. I'll be keeping an eye on it.

Carpy
Click to expand...

You need to find a frame shop / alignment shop with someone old enough to remember bending Ford I Beam front axels to correct camber. A straight axle has to be bent to correct camber & toe. :wink: (there is no caster on straight axles) :roll:
 
The axles bolt or u bolt to the frame. So I can't see why the axle mounting could not be moved forward or backward on either side. A good frame shop should be able to handle this or bending an axle.
As far as adjusting tongue weight if your setup will allow it moving the bow stop frontwards or backwards was an option for us. With our new boat the truck seemed like it bounced a lot after the trailer hit a bump. My thinking was that the boat was a little well too balanced. We slid the bow stop forward three inches; problem solved. My thinking is that if you need a weight distribution hitch you need a heavier duty tow vehicle. JMHO.
D.D.
 
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