Gas struts... GAH!!!!111!

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Gas struts... GAH!!!!111!

Postby Boreal » Fri Aug 04, 2017 10:59 am

Been searching around the site, and find myself to be in exactly the same situation as this fellow: http://www.tnttt.com/viewtopic.php?t=58439.

I have the struts. Problem is, as everyone who has ever ordered and installed these things for the first time, I'm pretty sure they're broken upon arrival. They are 100 pound rated, but when I put ALL of my weight on them, I cannot even compress them a bit.

Now, I know all about levers and stuff, but it seems to me that I should be able to compress them at least a little bit. Of course the true test will be after installation, when they presto chango work, all of a sudden. But what if they don't, and I have three holes to fill?

Some (any?!?!) reassurance would help me here.
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Re: Gas struts... GAH!!!!111!

Postby working on it » Fri Aug 04, 2017 11:52 am

  • I couldn't get my gas struts (springs) to compress either, though I thought I should've been able to. I used 150 lb struts, 36" long, 20.5" retracted, with 10mm rod in a 22mm housing. Since they were almost twice as strong as I had figured I would need (based on on-line calculators, etc., I decided to use just one, centrally-mounted (well, slightly offset due to permanently mounted gear in the way). It seems that the struts need the leverage applied to be greater than their rating, which must be the nominal rating of 100 on yours or 150 on mine, that is constant throughout their travel (stroke). I had thought that the initial force would've been the same, but was much greater.
  • Once I had determined the ideal mounting points, a single strut opened the hatch exactly the way I wanted, as an initial rise to about 90 degrees, then I easily lift it up to 105 or 110 degrees angle (I use detachable prop rods of two different lengths, depending on how much height I need to have headroom under the hatch), and insert/lock-in my prop rods to prevent wind lift, and for safety. Previously, I had to struggle inserting and locking the rods (I use flagpole brackets on both ends), since I have a bad shoulder, and holding the hatch up with it was a painful chore. My design and installation saga can be found here: http://www.tnttt.com/viewtopic.php?f=21&t=61432
  • 125904 I made graphs and calculations that aided my install
  • 125896 I use prop rods to lock hatch in overhead position (sometimes w/extensions)
  • 125895 a single 150 lb strut was just right, though I ordered two
  • 2013 HHRv,"squareback/simple" TTT, semi-offroad? 4x8, 2000+ lbs travel weight
  • featuring: 3500 lb Dexter axle w/brakes & HD leaf spring system > riding on General Grabber 27x8.5-14LT tires, LED lighting inside, A/C & heat, AGM battery 12vdc, 110vac from extended run generator onboard or park power, Coleman dual-fuel stove & Northstar lantern
  • 147697148333
  • 148599125895148106
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Re: Gas struts... GAH!!!!111!

Postby Boreal » Fri Aug 04, 2017 12:02 pm

Thanks for that, and the photos. And the thread.

I think I'm going to just bite the bullet and drill me some holes and see for myself. What's to lose? :D
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Re: Gas struts... GAH!!!!111!

Postby tony.latham » Fri Aug 04, 2017 1:03 pm

I'm using two 120 pounds struts. I think if you could push them in, then the gas has leaked and the are "broken". I sure as heck couldn't budge mine either.

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Re: Gas struts... GAH!!!!111!

Postby Boreal » Fri Aug 04, 2017 3:13 pm

Got it done. Unusual geometry owing to my hatch design. Video here: https://vid.me/qlY3E

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