Spring rate vs trailer weight - how to decide ?

[adventurebuddies]

I've been reading on springs and have some confusion. It seems clear to me that the short, stiff trailer springs I have now are not ideal. I took two leaves out which improved towability substantially by reducing trailer feedback. I've also noticed the effect that trailer tire pressure has.

It's time to improve the trailer suspension though so I want to go to longer springs. At this point I'm thinking of the ARB EMU Samurai springs. I need a set up that is easily replaceable in the third world.

How do I determine the appropriate spring for
my trailer? I assume I need to weigh the fully
loaded trailer,right? Then what? Let's say the trailer weighs 2500lbs fully
loaded. Do I need springs at 1250lbs each? How does one choose springs that will lift the trailer the appropriate amount to clear the tires in the fenders but not sit too high?

Thanks for any advice.

 

[Root Moose]

I'd pass on aftermarket springs like the OMEs. Use regular factory Samurai springs.

 

[ntsqd]

When you can find them, spring rates are listed in lbs/in or comparable metric units. Say you find a 500 lbs./in spring. That means that it takes 500 lbs. to compress the spring one inch. To compress it another inch requires an additional 500 lbs, for the now total of 1000 lbs. to compress the spring 2 inches. Taking your 1250 lbs./in example spring, the trailer will compress the springs 1 inch, but a set of 625 lbs./in springs would be compressed two inches.

Absent any spring rate info then ideally you'd know what the weight on the donor's axle was, and how much that weight compressed the springs.
Or you can just use what others with similar trailers have used and see how they work for you. One advantage to leaf springs is that if too stiff you can remove one or more leaves to tune the spring rate.

With longer springs will come the need to add shocks if they're not already there.

 

[Root Moose]

IIRC Samurai springs vary from ~170-190 lb/in depending on vintage.

 

[cruiseroutfit]

OME Dakar Sami springs range from 207-247 on the fronts. Rears are a two stage (overload) and range from 171/291 to 228/348. All in lb force per inch.