Branch Deflectors, anyone done em?

There are these:


If you have never been on McMaster Carr's web site...prepare to have your brain explode. The options are limitless....
https://www.mcmaster.com/

 

Now you have me thinking about the spring load. For me, I will be moving fairly slow through heavily wooded areas where the limb risers will come into play so I don’t thing the wires will get a significant impact on them; however, I have had a small tree get pushed down from driving over it or the bumper pushing it down then once it clears the tire or bumper come flying up and smack the side of my truck. In one case one limb almost broke my passenger side window. For this reason, Im thinking a significant spring would be advisable.

McMaster-Carr identifies spring tension with three metrics:

Made of stainless steel, these springs are more corrosion resistant than steel springs. They're also easier to extend than steel springs. As you stretch an extension spring, it gets harder to pull. Minimum load is the amount of force required to start to extend the spring. Maximum load is the amount of force required to fully extend the spring. Spring rate is the amount of force required for every inch or millimeter of extension.

302 stainless steel springs have good corrosion resistance.

316 stainless steel springs have excellent corrosion resistance.

The steel springs I have now have the following specs:



If I were to upgrade to a stainless steel spring, I would probably go with this one that has these specs:



Honestly, if a spring is used in the wires, Im not sure what purpose a turnbuckle would serve. I agree is you are running a spring from a bumper to a roof rack, you defiantly need a spring in the wire due to flex. And as you said what is the sweat spot for spring tension.

TacoTuesday, I like the idea you had in post #30 with a bar projecting forward of the roof rack to raise the angle of the limb riser but my concern would come when the limb risers are not used (such as day to day driving) and having that bar projecting from the roof rack. Perhaps, a flat bar with a long channel cut out of it and two bolts mounting it to the roof rack. When not in use the bolts are loosened and the bar retracted along the side of the roof rack then the bolts are tightened. When used, you simple loosen the bolts, slide the bar forward, then tighten the bolts. Something like this:

 

Moved the bracket higher and tested the Home Depot springs to see what happens. No dice, they’re too weak.

on the plus side at least McMaster seems to list every spec imaginable on their springs.



Pretty sure I have a luggage scale somewhere. That might be a way to figure this out.

1. incorporate scale in line, and set proper wire tension. Note weight on scale
2. Order a spring of that weight (whatever the term for that spec is). Or a higher weight than that, to ensure the wire is tensioned.
3. Or if at a store, find a spring that looks better, and pull on it with the scale against a wall to verify it’s the desired weight



probably doesn’t have to be precise and can be eyeballed in terms of length, width, thickness
stronger spring that remains compressed when not pressured by a tree branch would be ideal so there isn’t open spring gaps for things to snag on. Or constant force to cause fatigue.
black would be nice but if it’s stainless oh well. Short or medium would probably look better than long.
the fact that this guy's spring is still compressed while mine is not also tells me whatever 10lb I got is inadequate



apparently this stuff is common in aviation, deck railing, boating

finally figured out what one quick release is called (there's many)
saw the price. Nevermind.
Highfield Lever




or, also expensive: quick release lever



I may need to tape a scale to a tree and throw it on my truck to conduct an experiment



it's quite possible that to figure out The Spring, could require Addition, even Multiplication



or, maybe at the end of the day I'm gonna have to change cable length depending on room of the turnbuckle, to accommodate the longer distance switching to bumper
Rather than try to cheat my way around that by stretching a spring as "universal"
in other words, picking one that isn't stretched, and setting the length elsewhere.
Whether the spring ends up being one with a 50lb rating, or 30lb - whatever the common strength of a tree branch is (never measured that)

whatever, probably doesn't matter, because it's all more give allowed during bumper flex or impact, than would be had with a solid cable that has 0 give; the original point behind a spring for this.

Perhaps the answer lies within the size and strength of the average tree branch



these pictures might help




actually...this could be the solution...

 

mounted a bumper bracket from Amazon using 1.85” rubber sleeve adapter



Gotta figure out how to mount to that. One way could be mini shackle looped into the bracket Home Depot sells.



Slid the bracket outward as much as possible while keeping it on the flat straight part of the tube before the curve bend

tried a stronger ~16lb spring and noticed it has less expansion and allows for more tightening of the cable, better than the weak 10lb or less spring I tried

probably gonna get some free twine to use as a mockup string to check path clearance and length

 

I swear I'm not trying to be mean, but watching you guys try to figure this out is funny. You ought to see some of the setups in Australia; I'm sure you could search some of the Aussie 4wd forums and find plenty of pictures and a lot of different descriptions on how guys did theirs. https://duckduckgo.com/?q=austrlalia+4wd+limb+riser&t=newext&atb=v314-1&iax=images&ia=images

Here's a ghetto setup for the cheap amongst us: https://***************/2024/01/17/diy-limb-risers-tacoma/
There are a bunch of these Chinese kits all on ebay: https://www.ebay.com/itm/Steel-Adju...018-Jeep-Wrangler-JL-Accessories/202496782628
You can type "Limb risers kit" into Amazon and find various Chinese kits and they're on the different wish/alibaba/whatever sites too.


The spring in a spring things are sometimes called "porch springs" but they're probably stronger than what you're looking for.