Spring Over Axle (SOA) trailer conversion

   / Spring Over Axle (SOA) trailer conversion #1  

joshuabardwell

Elite Member
Joined
May 6, 2012
Messages
2,926
Location
Knoxville, TN
Tractor
Bobcat CT225
I am really tempted to do an SOA conversion on my trailer. The trailer rides low enough that I have to have a really long shank on my WD head in order to get the trailer to ride level. Even worse, the spring bars scrape on the ground sometimes, if I go over a bump or a dip. The extra 4-6" or so would really make a difference, I think.

I have researched the topic extensively, in large part right here on TBN. My axles have camber, so I will need to have new spring perches welded on the top of the axle. I'm really torn on whether to proceed. Mostly, I'm concerned that I'm going to end up messing up my trailer's alignment and wear out my tires, or cause the trailer to pull badly. I guess what I'm looking for is input as to whether this kind of thing is fairly robust, or whether it is fairly sensitive. If I eyeball the location of the perches directly across from the existing ones, and eyeball them parallel, is it likely to be good enough? Once the trailer is assembled, do I need to confirm the alignment, or is it pretty much likely to be good to go? Will the existing spring mounts force the alignment to be correct, for example?

I have read that you can't re-use U-bolts, because the threads won't re-tension right. I've also read some people express concerns about weakening an axle by doing welds on it because the metal is supposedly relatively thin. Any validity to these concerns?

Thanks!
 
   / Spring Over Axle (SOA) trailer conversion #2  
Dexter makes a kit that uses studs and long nuts to square up the axle perches and it comes with new u-bolts. The u-bolts hold the perches to the axle but I welded mine on anyway. This was on my old camper with 3500lb axles.

DSC00239.jpg

DSC00231.jpg
 
   / Spring Over Axle (SOA) trailer conversion
  • Thread Starter
#3  
I'm familiar with that kit, although I didn't realize that it was self-aligning like that. That's cool. I thought you were supposed to weld the perches anyway, though. The etrailer FAQ on the product seems to indicate so. Can you confirm that welding isn't required per, I don't know, the instructions in the kit or whatever? If so, the cost of the kit might balance out the cost of not having to weld the perches on.
 
   / Spring Over Axle (SOA) trailer conversion #5  
I have done it a few times to customers trailers and always did the welding. As for the u bolts use a torque wrench and retorque after lowering the trailer and with a load on it. Torque them again with load at 50 then 500 miles.

Chris
 
   / Spring Over Axle (SOA) trailer conversion
  • Thread Starter
#6  
Well, I'm going ahead with it. Here are some photos.

IMG_1040.jpg

I put jack stands behind the back of the trailer...

IMG_1041.jpg

Then raised the front of the trailer with the loader...

IMG_1042.jpg

And set a cinderblock under the jack. Currently, the tires are removed and the U-bolts are off. The conversion kits should come via UPS tomorrow (Friday).
 
   / Spring Over Axle (SOA) trailer conversion
  • Thread Starter
#7  
In case I decide to go ahead with the tack welds on the perches, what is the typical wall thickness of a 3500 lb axle? Diameter is 2 3/8".
 
   / Spring Over Axle (SOA) trailer conversion #8  
   / Spring Over Axle (SOA) trailer conversion #9  
wow-- your trailer looks identical to mine. I'll be watching this thread for sure- its just that I dont have the problem you say you have on yours.
 
   / Spring Over Axle (SOA) trailer conversion #10  
I would seriously think about putting something a lot more substantial than that cinderblock under the trailer jack.

If you are really into concrete, a solid pier block would be a lot stronger in compression. Even stacked 2x lumber is better than a cinderblock.
 
 
Top