It has no spring in the axle at all. ?

[Cam A]

I'm off to the exotic province of Saskatchewan tomorrow on a trailer-hunting trip; when I read Gina describe a trailer as above. Do you test this by jumping up and down in the trailer? And what are the consequences if it has no spring in the axle? Cost to fix $CDN?

[Bill MacDermod]

It would essentially be like having a solid axle with no give except what the tires would allow, pretty rough ride

[Ryan Kennelly]

My trailer has a torsion suspension, and it really stiff! But the last time I had it out, We put a thousand pounds of stuff in it. Then it Rode great! I would say that you would not benifit from jumping up and down in it. Tow it down the road, If it dribbles like a basket ball, then its stiff.

[Roger H]

Actually, the 'jump test' is about the only way to determine whether or not a torsion axle is still active.

You want to be outside the trailer with the wheelwell at about eye level. Note the relative position of the top of the wheelwell to the sidewall of the tire. Marking the tire sidewall with chalk may be helpful.

Then, have someone (larger someones will cause more movement than smaller someones) inside the trailer jump up and down a few times. You should see the fender well move up and down in relation to the side wall of the tire and your chalk mark. The total axle travel is limited to about 3", so it won't move a great deal, but it should move. If you see movement, then your axle still has suspension. If all you see is sidewall flex, and no movement of the fender well over the tire, then the axle has no suspension left and is due for replacement.

Roger

[pjanits]

If someone in your trailer can cause the axle to flex 3 inches while jumping up and down, I would say that axle is shot or the person is too big.

I went back and reread your post Roger and you say whay I said. So I could have not said anything.

If it moves an inch that would probably be ok.
I figure it's just like the suspension on a car (it looks different ,but the results should be similar), the same tests apply.

[Brian B-P]

...I figure it's just like the suspension on a car (it looks different ,but the results should be similar), the same tests apply.

I wish trailer suspensions were more like a car. In practice, they are cheap, stiff, short-travel, and underdamped compared to any acceptable car or light truck. Not that I have a strong opinion on this subject

The 3" (roughly) deflection is from no-load (jack up the trailer so the wheel is not supporting any weight) to full bump deflection. From no-load to full load (2000lb axle loaded to the whole 2000lb, even if the trailer is only 1000 lb by itself) is more typically only 2" for the axles in smaller trailers. For details, see spec sheets such as the Dexter Torflex 1000-2000lb Application Information.

So how much should the trailer move vertically when you jump in it? Well, a 200 lb person stepping in (not jumping) should move it a small fraction of the amount which 2000 lb of full load does, so it will be a small fraction of an inch. Jumping might double that, I guess. The tires probably give about as much as the suspension - but that suspension travel is still important.

I have a leaf-spring beam axle (not rubber torsion) but the situation is about the same. Moving about the trailer (without stabilizer jacks in place) causes noticeable movement, but I don't how much is suspension travel.