Spring capacity by dimension

[bluzharp]

When I bought my springs and axle for the offroad teardrop, I ordered a 3500# axle to get the bigger brakes and bearings but I indicated I wanted 1000# springs instead of the 1750# springs. Well he piled up all the stuff I needed on the counter and I wrote a check and went on my merry way. On the first outing it was obvious the springs were way too stiff so I removed the bottom leaf. It was slightly better but I had no clue what spring ratings I was dealing with. I found this nifty chart that allowed me to identify my springs.

http://www.stengelbros.com/UtilitySprings.htm

The original springs were 1750# each (3500#). With the bottom leaf removed, they are 1000# each (2000#). The springs are still too stiff so I ordered a pair of 740# springs that are 28" long instead of the 24" springs I have now. the trailer weighs roughly 1100# loaded so these should work better.

[teardrop_focus]

Thanks for posting that link! (I'll get a chance later to check it out..)

Although I plan on using a torsion axle, this info can be helpful to those who're using previously-pwned trailers with no printed spring specs...

The original springs were 1750# each (3500#). With the bottom leaf removed, they are 1000# each (2000#). The springs are still too stiff so I ordered a pair of 740# springs that are 28" long instead of the 24" springs I have now. the trailer weighs roughly 1100# loaded...

Let us know how that works out.

[bluzharp]

I finished mounting the new springs this weekend and dragged the trailer out of her pen for a tour around the 'hood. There is a huge difference in how she rides now. Bumps are absorbed and there is no "jolting" when going through dips in the road at intersections or over speedbumps. Highway performance is great and the expansion joint bumping isn't transmitted to the truck anymore. The lighter, longer springs are a good upgrade for my trailer and they will be much better on the trail than the short, stiff ones were.

When I get back from Mammoth/ June Lake/ Bishop/ Yosemite in a couple of weeks, I'm going to put in some bump stops and rearrange the fenders a little. I am also thinking of moving the axle further forward to lighten the tongue some.

[teardrop_focus]

Great news; good to hear.

Was your trailer weighing 1100 lbs for the lap around the 'ho0d?

Help me out, here... so, each new spring is rated at 740 lbs... totalling an almost-1500 lbs spring capacity... and your trailer rides ten times better than before?

Outstanding. This has me thinking of using a traditional solid axle rather than a no-bearing rubber torsion axle which can develop negative camber through sag. Dexter Axle sells both, and when I talked to an axle engineer there and asked him if the torsion axle was much lighter than a leaf/solid axle setup, he said, "No, not really".

I appreciate you taking the time to post your experience with this, bluz.

[bluzharp]

I have made a couple of other modifications since I weighed it, so I need to re weigh it. It isn't a lot heavier than before though. It's still in the 1100-1200# neighborhood I suppose. The tongue weight is about 165# so there is approximately 1000# over the axle. The point is the original springs were wrong and overly stiff, hammering the crap out of everything. Until I found the spring chart, I didn't know what I had.

As far as torsion vs. leaf spring goes, I think it comes down to what are going to do with your trailer. Offroad, washboards, rocks and the possibility of trail damage and repairs rules out torsion axles. On the other hand, if you are just cruising highways and decent roads, the torsion axle is fine. In my case, the spring rate was incorrect and it was a cheap and relatively easy task to make a major change in the suspension.

[teardrop_focus]

td_focus

so, each new spring is rated at 740 lbs... totalling an almost-1500 lbs spring capacity... and your trailer rides ten times better than before?

bluzharp

The point is the original springs were wrong and overly stiff, hammering the crap out of everything. Until I found the spring chart, I didn't know what I had.

I got that.

This was exactly why I posted in your thread... to say that you've done what few people seem to have done... and that's to fine-tune your trailer's spring rate to your actual load, resulting in a superior (trailer) ride.

I'm really only posting in here to confirm this, and to congratulate you for getting your leafspring setup to ride as nice (just about) as a rubber torsion axle setup.




As far as torsion vs. leaf spring goes, the leafspring setup w/ a solid axle wins every time for the preservation of wheel alignment. The lighter-weight torsion axles have no metal bearings in the trailing arm geometry; they rely soley upon the rubber "fill" to maintain trailing arm alignment and over time the rubber will deform, changing wheel alignment, particularly in regards to camber.

And again, when I last spoke to Dexter, the axle engineer answered my question, "So, isn't a torsion axle setup lighter than a leaf-sprung, solid axle setup?" with, "No. Not really."

Go figure.

To summarize, this is only bench-racing over the merits of both setups; when a lightweight trailer's leaf spring setup is properly calibrated it can result in a very nice-trailering trailer.