Gas lift struts for trailer question

McMaster-Carr has a good selection of gas springs of the most common sizes:

htp://www.mcmaster.com

To estimate the force required to hold the trailer top open, the easiest way is to just use bathroom scales or similar to see how much force is required when the trailer is fully open. But that only works well when the geometry is fairly straightforward.

Thanks, Bob K.

On Monday, December 9, 2013 7:52:49 PM UTC-5, Bob Kuykendall wrote:
To estimate the force required to hold the trailer top open,
the easiest way is to just use bathroom scales or similar
to see how much force is required when the trailer is fully
open.

Right - Prop the trailer open using a 2x4 cut to length,
propped at the spring attach, angled in the direction of
the spring, against a scale held in the proper orientation.
You'll need a helper to prevent dropping the trailer
top when you do this and a 2nd 2x4 for the opposite side...

We're waiting for the video.
DON'T DROP THE TRAILER TOP !

Have fun, See ya, Dave

PS: Detach the defunct springs to get a correct reading
PPS: You may not need to lift the top all the way up
iff the geometry is such that the spring load is constant,
but you do need the spring length with trailer open...

On Tuesday, December 10, 2013 8:53:58 AM UTC-5, Dave Nadler wrote:

You'll need a helper to prevent dropping the trailer

top when you do this and a 2nd 2x4 for the opposite side...

DON'T DROP THE TRAILER TOP !

Having replaced the struts on my trailer just last summer by myself with no maiming, I have relevant experience.

Several local wags suggested suspending the trailer lid from an overhead beam in the hanger and I added a "ratcheting lever winch" (aka a-come-along) to the mix. The raised lid resembles a guillotine or maybe a giant chop saw, especially since you will need to put precious bodily parts on the block repeatedly.

The 2X4 is a good way to measure the force, but not needing to do that I used a 2' X 4' piece of 3/4 plywood (Advantech actually) with one end cut to the matching angle. One end of the plywood fit in a rib of the corroborated floor and the other end fit in the U-lip edge of the top. Tapping the plywood with a mallet fore-aft I was able to make very precise adjustments on the height of the lid and this was needed to align the strut mounting bolts precisely. The suspending rope had some stretch, so the plywood and the rope shared the load.

It was nice to have a totally foolproof and redundant way to hold up the lid because it could easily amputate something, possibly your head. Before I thought of the plywood "wedge", I struggled unsuccessfully for an hour to align the bolt holes of the strut.

Another advantage of doing this under cover is that you don't have to worry about the wind while the lid is raised and precarious. Also be sure to replace the struts in pairs and keep the good old one for an emergency spare.