Converting From Leaf to Torsion

[michaelwpayton]

Does anyone have any experience/knowledge re converting an off-the-shelf trailer (maybe this one: http://www.tractorsupply.com/trailers-towing/trailers/utility-trailers/carry-on-trailer-reg-no-floor-trailer-1000215 from leaf springs to torsion? Cost, difficulty, suggestions, advantages/disadvantages, etc.

[Shadow Catcher]

I have not done this and would not. It is however possible. The frame on the trailer is angle and would have to be reinforced substantially spring hangers removed etc. I would think you would be money ahead buying a purpose made frame or having one built, that will take the torsion axle. Otherwise you will be throwing away half the value of what you buy, axle, wheel, springs.

[bve]

Mine is not an 'off the shelf' frame, however I did do a conversion to a torsion from leaf suspension.

In my case the frame was an existing 'C' channel frame which had 30+ year old leafs, axle and hubs - all of which I would have replaced at a cost of about $180 - $200 Cdn (for leaf, axle, hangers etc.) The old hubs were 4 bolt.

I was able to get a new - used torsion axle set-up for $100 (with 5 bolt hubs) + $60 steel to mount it + $150 labor on welding (there was some other welding done not related to the axle). The only reason the economics of this worked for me is time - the costs have been spread over 3 years.

The economics also work because I was able to replace the modified frame (which I was using as a utility trailer) with a free replacement to use for utility purposes.

If you consider the cost of the TSC trailer, plus the costs of the mods, I'm sure you could get a custom frame built for close to - if not less than - the costs of modifying the TSC trailer.

[michaelwpayton]

Thanks guys. The parts to build from scratch work out to $450-$500... for a torsion-based 5'x10'. I haven't recevied any quotes yet, for the welding.

[dh]

One tidbit to remember, leaf springs spred the weight over four points, a torsion axle, 2

[rladams39]

One tidbit to remember, leaf springs spred the weight over four points, a torsion axle, 2

true but a torsion axle Has about 32 square inches of mounting surface per side, compared to about 4 square inches per side on spring mounts.

You might be spreading the weight out over more points but the pounds per square inch of mounting area will be alot more on springs....

[michaelwpayton]

dh and rladams39...

Excuse my ignorance... but, are you guys discussing which is a better design... leaf or torsion... in general? If so, I would love for you to "bring it up a notch" so an idiot like me can more fully understand your points :-)

[bve]

dh and rladams39...

Excuse my ignorance... but, are you guys discussing which is a better design... leaf or torsion... in general? If so, I would love for you to "bring it up a notch" so an idiot like me can more fully understand your points :-)

I think the points they are trying to make are a bit moot... If I am interpreting them correctly?? dh is suggesting the load is spread over a greater number of points of contact, therefore leafs may be better. rladams39 believes since the surface area the torsion axle contacts the frame is greater it would be better.

From my perspective the advantage of the torsion is in the 'independent' nature of the suspension, perhaps faster sway/bounce recovery and the ability to get a potentially lower ride height, on the other hand with a drop axle and leafs you could probably get just as low - if not lower, and it is much easier to 'tune' the ride with leafs - add or remove a leaf, change the arch, etc.

Ultimately it comes down to properly matching the capacity of the suspension, regardless of type, to the load it has to carry - if either type is way over/under rated for it's load the ride won't be great.

You haven't really indicated 'why' you wanted to swap to torsion from leafs, there are plenty of tears built on leafs, and to be honest the only reason I chose the torsion was it happened along at the right time and price - while I was looking for a replacement axle.

[Arne]

I threw my h/f spring set up out and bolted on a torsion axle. I double nutted the bolts.

case closed. for me at least. 2 years, and still bouncing down the road.

[eamarquardt]

I think that a frame with a torsion axle mounted to it might be a bit more stressed than a frame with springs. I just measured a torsion axle mounting plate and it is 4.5" wide by 9 inches long (40.5 square inches). But the mount is only in contact with the frame's side member for 4.5 linear inches. The spring hangers on my teardrop frame are 26" apart. Just for argument say we've got 3 feet of rear overhang on an 8 foot teardrop body from the center of the axle. You have a lever with 33 3/4" on one side of the folcrum and 2 1/4" (from the edge of the mount to the center of the axle) which is a 15 to 1 advantage lever arm in favor of bending your frame at the point where it is stressed the most. With the same 36" rear overhang and a spring suspension you have 23" on one side of the folcrum (the rear spring mount) to 13" (spring mount to the center of the axle where your frame is stressed most) which is only a 2 to 1 ratio lever arm. I know of only one person with a bent frame right now so (and they are using springs) but I suspect there are more out there. I got a pair of half axles and plan on building a small motorcycle trailer. I plan on reinforcing the center area of the frame a bit where the half axles mount. Cheap insurance.

If my reasoning is off, I'm open to enlightenment.

Cheers,

Gus

[bobhenry]

God I really hate to say this but I am in your camp on this one Gus.

When you are trying to bend a pipe you don't put in over both knees, just one at a time.

We are forgetting that the structure above will afford a truss effect to aid the frame to resist bending if the construction methods are sound and connections are well glued and fastened. Many tiny trailers on this forum have little or no metal frame and are on the road thanks in large part to the strength of the trailer body itsself.

I would be much more concerned with tongue failure on the light weight stamped steel trailers



http://www.tnttt.com/viewtopic.php?t=1980&postdays=0&postorder=asc&start=0

[angib]

I don't think the way the load is transferred to the frame is important - as bobhenry says, it's tongue strength that's critical, not middle-of-the-frame strength.

I think a torsion axle puts less load into the frame because it is a fixed tube that is attached to the frame - a leaf-sprung axle relies on the frame strength to hold it in place, for example to resist the shackles rotating sideways when cornering. But I still don't think it's significant difference - if a frame is strong enough with a torsion axle, it'll be strong enough with a leaf-sprung axle.

The one signficant difference between torsion and leaf-spung axles is that the torsion axle has some damping from the rubber - not a lot, but some.

The leaf-sprung axle has some friction in the springs but this isn't very useful - it stops small movements but doesn't control big movements.

But I think 'user preference' is the biggest difference - people seem to be naturally inclined one way or the other, a bit like Ford .vs. GM.

Andrew

[rladams39]

Sorry for the confusion, I have had many trailers of one sort or another with both style axels, i agree that it is personal preference, the only thing i noticed was with a really heavy load the torsion axels would wear the tires a little more uneven, could have been from worn torsion rubbers...

We had 2 horse trailers, both were the same size and very similar in construction, one had torsion axels and the other spring axels, the one with the torsion axels did seem to bounce a little less, and you could tell a difference in pulling it on really rough roads, not sure if it was because of the independent nature of the axels or what...

If you want to convert from spring to torsion, just make sure you have a solid mounting surface and you should be fine, if your body is built tight and strong you should be good to go..

[michaelwpayton]

... You haven't really indicated 'why' you wanted to swap to torsion from leafs, there are plenty of tears built on leafs, and to be honest the only reason I chose the torsion was it happened along at the right time and price - while I was looking for a replacement axle.

The reason I asked the question - I was planning on doing a custom, torsion-based, trailer... i.e. buying the parts, cutting myself and then having it welded... but, along came an opportunity to get an off-the-self, "for next to nothing," so I thought... maybe... I should use that as my starting point.

Thanks for all the replies, comments, opinions, etc... I'm learning a lot.

[vtx1029]

I may be wrong but I've been told most torsion axles are made to order. A couple of years ago we lost a wheel bearing on our 18' trailer. It ended up welding the nut onto the spindle and had to be cut off. We lost 2 days of our vacation making phone calls, running from town to town looking for parts. We ended up welding another nut in place after installing new hub and bearings so we could limp it 1200 miles home because a replacement axle would have been a 2 week wait. Had it been a leaf sprung axle it would have saved us a crap load of $$ and time.... Not saying I don't like torsion axles just another aspect to think about.