Straight or drop axle?

[Martinjmpr]

(crossposted from tnttt.com because this seems to be a more "active" forum. )

In an effort to both lower and lighten our Teardrop "Bubbles", I have removed the old, heavy Dayton mobile home axle (build thread link in my signature below.) Not only was this heavy, but it was also "over-slung", that is, it was in a "spring-over-axle" configuration, apparently to give it more height (I guess the guy who built it intended for it to go off road?) Here is the original arrangement:

But now that's off and this is what I have left:

As you can see, there looks to be maybe 6"-7" between the top of the leaf spring and the frame.

Now my original plan was to put a straight axle in, about a 2000lb round axle, which has a diameter of maybe 2", and in an effort to keep the height down, I was going to "under-sling" it (that is, go to a spring-under-axle configuration.)

But, assuming the axle with the axle seat is maybe 3" max, that leaves at most 3 - 3 1/2 " of upward travel before the axle hits the frame. Does that seem adequate? I have never built a trailer so I don't know. I can say that the trailer is on the heavy side. It was 1100 lbs when I weighed it last, but my guess is that the Dayton axle and wheels accounted for at least 150lb of that and the new axle will be much ligher, but my guess is that it will still be probably 1,000lb. I will also say that the springs are rather stiff, so I'm not sure if I'm worrying unneccessarily or not.

Now, if that wheel travel appears to be inadequate, my other option would be to get a 'drop axle' and mount it under the spring. That would give me the full 6 - 7" of travel and still allow for a lower stance. Are there any specific problems or issues with drop axles?

Keep in mind this is not an "off road" trailer. The furthest we normally go off pavement is on well-graded dirt roads (FS/BLM roads) so I don't need tremendous wheel travel, but obviously I don't want the axle slamming into the trailer frame if I go over a curb either.

Thanks in advance!

 

[4x4x4doors]

If you took that jack setting under the spring and started cranking, how much would the spring deflect before the trailer body moved? In other words, how soft are those springs? Unless they're super soft, I would believe that you've probably got plenty of room.

 

[elmo_4_vt]

I agree... If they are standard "trailer" springs, they probably only move about 2" total from no load to full rated load. I'd go spring-under-axle with a 2000 (or probably 3500lb) axle and be done with it. Even though you don't need the 3500lb axle, it may be worth it for the better bearings you get and the ability to have standard trailer brakes. IMHO.

Don

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[Martinjmpr]

I agree... If they are standard "trailer" springs, they probably only move about 2" total from no load to full rated load. I'd go spring-under-axle with a 2000 (or probably 3500lb) axle and be done with it. Even though you don't need the 3500lb axle, it may be worth it for the better bearings you get and the ability to have standard trailer brakes. IMHO.

Don

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Don't want/need brakes so I think a 2000lb axle will work fine.

 

[bunger]

The 2000lb axle may limit your wheel/tire choices.
The 3500lb axle will have more stud configurations available so you will have many different wheel options.
A lot of us run the same hub configuration on our trailers as the tow vehicle, so we can use the tow vehicle spare if needed, and not carry a spare for just the trailer.

 

[njtacoma]

Repeat what has been said about spring under, I think you'll be fine.

Conventional Trailer springs (on a single axle application) typically only travel when hitting a bump (speed bump, drainage, etc). Other times they "articulate" around the hitch, so the springs themselves move very little.

For added security you could add a small bolt on bump stop to the frame. Energy suspension has several in their "universal" section that would probably work.

 

[Martinjmpr]

The 2000lb axle may limit your wheel/tire choices.
The 3500lb axle will have more stud configurations available so you will have many different wheel options.
A lot of us run the same hub configuration on our trailers as the tow vehicle, so we can use the tow vehicle spare if needed, and not carry a spare for just the trailer.

Hmmm...I hadn't thought about making the bolt pattern the same as my tow vehicle, but in any case, I'm trying to keep it light and simple as much as possible. To compound that issue, we will actually have two tow vehicles, my 4runner with a 6 lug 16" wheel will be the primary but the secondary will be my wife's 95 YJ with a 5 lug 15" wheel, so as cool as it sounds to have the tow vehicle and trailer using the same spare, I don't think it would work for me.

Repeat what has been said about spring under, I think you'll be fine.

Conventional Trailer springs (on a single axle application) typically only travel when hitting a bump (speed bump, drainage, etc). Other times they "articulate" around the hitch, so the springs themselves move very little.

For added security you could add a small bolt on bump stop to the frame. Energy suspension has several in their "universal" section that would probably work.

Yeah, I had thought about a bump stop. I would at least feel better if I knew the axle couldn't ding off the frame although I can't even imagine how big a bump that would have to be! It would probably damage the whole trailer to hit something that hard!

 

[htek]

If you go spring under with the new axle and still aren't comfortable with the clearance, you could always swap to slightly longer shackles to get the needed room.



Sent from my Nexus 7 using Tapatalk HD

 

[Martinjmpr]

If you go spring under with the new axle and still aren't comfortable with the clearance, you could always swap to slightly longer shackles to get the needed room.



Sent from my Nexus 7 using Tapatalk HD

Good point, I never thought of that.

Went and looked at my little Utility trailer last night, noticed it's spring-under-axle with even less travel than the TD and I've never had an issue with it, even fully loaded. I think we'll be fine with a straight axle.