active bumpstop used as a shock absorber substitute

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Re: active bumpstop used as a shock absorber substitute

Postby working on it » Mon Sep 22, 2014 9:22 pm

working on it wrote:Rob- that's exactly what I'm doing- experimenting. At first look at the bumpstop, un-cut, it has the potential of creating a very hard secondary impact on the axle tube (I'm not worried about frame impact, thru the two pieces of angle stock- that load will be spread out over a large area). But the poly, after modification, is really quite pliable (now), and will only stiffen up progressively, after the springs flex upward a lot. What is most important to me is to limit the extreme push/pull on the rear hangers...
I just returned from a short trip to Cleburne State Park, where I experimented with various sidetents, sidetables, food storage and usage, water consumption, trailer loading, truck-bed loading, bathroom use!, ice requirements...everything I could think of, for deciding what I need and what I do not need. I also used the occasion to test my trailer hitch phobia (I actually towed home without using my Weight Distributing spring-bar attached!- first time in years) And I intentionally ran my trailer wheels over (minor) potholes and whoop-de-doos (as I neared home), as the penultimate test of the active bumpstop concept. Perhaps a better name for the piece would be "a progressive, multi-stage, shock dissipator". I set some items in strategic locations inside the trailer, to measure how much displacement occurred going over bumps. And I watched the effect on the trailer for each bump as it occurred, in my mirrors. Not scientific, but it gave me an idea of how my design was faring. I normally tow with the WD hooked up; it limits the movement of the trailer, since the much heavier tow vehicle exerts a stabilizing influence on the trailer over rough roads. When I removed the WD hitch, I could see more reaction from the trailer, but the difference was not as much as I had expected. The test objects inside the trailer were all moved, but not far; since I left the ligament between bumpstop sides attached, I see now that if I sever it (#3 in the photo), the remaining harshness in compression will be reduced to a negligible amount.
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As I intend to eventually convert to an off-road multi-axis coupler (kudos to Woodyperk6), I'll need the added "give" in the suspension. Testing will continue, as I am an inveterate, unabashed, incessant tinkerer.
2013 HHRv "squareback/squaredrop", rugged, 4x8 TTT, 2225 lbs
  • *3500 lb Dexter EZ-Lube braked axle, 3000 lb.springs, active-progressive bumpstop suspension
  • *27 x 8.5-14LT AT tires (x 3) *Weight Distribution system for single-beam tongue
  • *100% LED's & GFCI outlets, 3x fans, AM/FM/CD/Aux. *A/C & heat, Optima AGM, inverter & charger(s)
  • *extended-run, on-board, 2500w generator *Coleman dual-fuel stove & lantern, Ikea grill, vintage skillet
  • *zinc/stainless front & side racks *98"L x 6" diameter rod & reel carrier tube on roof
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