Axle upgrade, single to double

[William8979]

Hi,

I have a 55 single axle 26' Overlander. Has anyone done an upgrade to a double axle? Seems like this should be do-able and a safer trailer in the end.

Thanks
Will

[markdoane]

I haven't done it, but I did replace the single axle and wheel wells on my '59. I assume you would center the new axles either side of the original, unless you plan to move the center of gravity by adding tanks or batteries.

You will need to move four outriggers. That may give you an opportunity to re-arrange some of the interior furnishings, like the refrigerator and stove.

Beyond moving the outriggers, you will need to fabricate new wheel wells (not a big deal), and open up the wheel openings. I assume you will be putting in torsion rubber axles instead of leaf springs. I think you can go with fairly light axles, like 3500#.

I think it's very do-able, and good luck.

[Over59]

Why would you do that?

[till]

In addition to what Don has said, If you change over to torsion axles, you will have to fabricate mounting plates for the axles.

It realy comes down to weather you want to do a fair amount of welding.

Other wise, as Don said, it is do-able.

[Inland RV Center, In]

William8979

You can use 3000 pound Torsion axles with that change.

We have the axle mounting plates.

3500 pound axles will beat that trailer to death.

Use extreme caution as to where you will locate the tandem. Too far forward will cause a huge lack of tongue weight, which will give you a sway that cannot be eleiminated.

The best way is to measure the same size trailer, but a later model that has tandem. That will give you a good starting point.

Andy

[59toaster]

It could be done but with a good sway control set up the question is why do it at all.

Check with "Till" he is parting a 67 Overlander and will have the wheel tubs.

[rluhr]

I was wondering the same thing. What makes you think the Overlander is unsafe as designed? I would think a properly installed sway-reducing hitch combined with reasonable tow vehicle would be fine. Adding an axle is a major experiment, in addition to introducing additional risks if done improperly.

[William8979]

Thanks for all the input. My reasoning for doing this is basically safety in numbers. If one tire goes, well.... That said, I'm not set on doing this. I am just brain storming this project and have no experience with single axle trailers this size. I will be using sway controls. I'm up for doing the work, but if there are good reasons not to do this I have plenty of ways to spend my time and money. Again, thanks.

Will

[Ken J]

Duel axle was a major improvement on the bigger trailers. They track better, you have a fair amount of weight on two tires vs four. And, as you point out it's better if you get a flat. Guess what I would do is if I had a single axle, I would live with it, make sure I kept the best tires on it and made sure I checked tire pressure often ( I know you should do this with double axle also). My 58 has the optional duel axle which I have to say does give me a higher comfort level - not sure it should because there are lots of single axle long trailers out there. I don't think I would go to the expense and difficulity of making it duel.

Ken J.

[markdoane]

Will,

If you have leaf spring axle, the spring mounting plate should keep the trailer upright if you have a flat tire. It might gouge an ugly scrape in the pavement.

That's one advantage of having leaf springs.

If you want to make it a little safer, you can add a skid plate to the bottom of the spring plate. That gives the axle someting to ride on if you have a flat tire.

Here's a picture of how I did mine.

[Over59]

Don. Can you show that installed?

[markdoane]

Originally Posted by Over59

Don. Can you show that installed?

Here's a long shot and a close-up. The skid is thick enough to protect the nuts on the U-bolts from being sheared off.

[Pick]

Not to mention the fact that you have to buy another axle, 2 more tires and wheels. With todays radial tire technology, and quality tires, such as Goodyear Marathons or Michelins, I would keep it a single axle and buy 3 new tires and be done with it.

[markdoane]

I think the reason I would choose to go two axles would be for increased load capacity, not for safety. I was able to increase the load rating on my trailer by 800 lbs by replacing the axle and adding a leaf to the springs.

The single axles from the '50s were marginal, even for the original weight of those trailers. When you start adding batteries, greywater tanks, microwaves and TV sets it's easy to exceed the original axle rating.

Here's a size comparison between the old and new axle spindles:

[Action]

Clearly Airstream thought enough of it to only offer dual axles on Overlander in later years. A single axle on a 26' trailer, no matter what the size of the axle, is pushing the edge at best. And Airstream thought so too based on later offerings.

>>>>>>>>>>>>>>>>>Action

[Anon]

I would like to see some photos if you do upgrade to the dual axles!
I like all years of vintage Airstreams but the old big ones with single axles always kind of distrubed me. It looked "wrong". I take into account the weight. Like someone else said; throw in a microwave, greay water tank and all that other good stuff and POOF it is too heavy.
Let us know what you do. I would love to see pictures of an older one that has been tastefully upgraded to dual axles.
As for tubs, I would look for a scrapped Airstream or Argosy and use those tubs.

[Over59]

Thanks for the pic Don. Is that skid plate a standard axel shop item or will they do that eye rowing thing when I ask for it on my new axles.?

[markdoane]

Originally Posted by Over59

Thanks for the pic Don. Is that skid plate a standard axel shop item or will they do that eye rowing thing when I ask for it on my new axles.?

I think they'll be doing tryouts for the olympic rowing team.

I needed to get new spring mounting plates because the new axle was larger diameter than the original. So it had holes drilled for 3" U-bolts instead of 2 5/8". It also had a higher weight capacity of 5200#.

I cut the original plates in half and used them to make the skids. I also had to fabricate new mounting posts for the shocks, because the shocks are now inside the frame, rather than between the frame and wheel.

The spring mounting plate is mild steel, available at any axle store. I had it welded by ultradog, but most welders could handle it without any problems.