Tire swing - suspended from horizontal line between 2 pines

[kzucas]

I have 2 large pines in my yard. They are branchless about 30' above the ground. My idea is make a tight line (using a large diameter rope from a crane) between the 2 trees. Then to drop down a rope in the center for the tire. My question is what is the best way to tie off to the trees and tighten the line? I have a friend that can climb. Any other suggestions are appreciated as well. Thanks!

 

[ArtB]

do NOT tighten horizontal line, leave slack (30 deg) to common point. 2 ea 8" long 3/8" lags holding on a plate with welded rope fastening point should work OK.
If you REALLY want a tight horizontal line for tightrope walking also, couple of 2 ton (a buried old truck chassis works nice) soil anchors and 3/8" stainless steel guy wires to 30 ft spot on trees ---etc....heh, heh...

Some more ideas

http://www.perfectunion.com/vb/attachments/general-****-chat/25185d1389993069-tire-swing-cartoon-govt-all.jpg

 

[ATH]

I'd get a couple of these from Wesspur or TreeStuff and tie the rope to them.

I agree you probably don't want it too tight...leave the trees free to move independent of one another.

 

[kzucas]

do NOT tighten horizontal line, leave slack (30 deg) to common point. 2 ea 8" long 3/8" lags holding on a plate with welded rope fastening point should work OK.

Thanks for the response! I obviously know what lag bolts are but I'm not sure what you mean by "holding on a plate". What is the reasoning for leaving slack in the line? To allow room for sway and growth without pulling on the lagged in anchors?

I was thinking of using a 1/2" steel ring or shackle for the center point that the swing rope will drop down from. Not sure if I would just slide the steel ring right onto the horizontal line or if I would tie a butterfly knot in the center of the horizontal line and attach the steel ring to the butterfly knot. I also am considering putting a swivel in the line dropping down as well.

 

[unclemoustache]

Don't wrap ropes around the trees. Use eye screws- the longest you can find. But realize the force will be to pull the screws straight out, so I recommend using two screws in each tree, and each at a slight angle.

 

[ArtB]

Plate would be a steel plate with 2 holes and a ring to attach rope welded to it - you do not want the swing to fall due to one lag letting go.

The slack it to reduce the sideways force on the trees. Say your fat uncle who weighs 200# decides to sit on the swing. The vector forces on a taut line between the trees could then be in the 5 or 6 TON range, enough to disturb the root ball. If you only left a 10 degree slack, the force drops to under 1 ton, for 30 degrees, it is only about 1-1/2 the weight supported.

When you said crane, assumed you would be using wire rope, but when you said 'knot' that threw out wire rope. Nylon would stretch to provide a few degrees of vector force angle. Dacron not much.
Yes, you do want to use a swivel.

 

[ATH]

With the slack, you wouldn't need a butterfly as the weight of the swing will keep it in the middle.

I'd personally just use one lag bolt in each tree. A 5/8" x 4" long lag isn't going anywhere.

 

[kzucas]

With the slack, you wouldn't need a butterfly as the weight of the swing will keep it in the middle.

I'd personally just use one lag bolt in each tree. A 5/8" x 4" long lag isn't going anywhere.

Initially I was thinking, but didn't explain, the butterfly knot would allow me to position the swing off-center to clear the shrubs. After looking closer I don't think that will be an issue anyway though.

Thanks everyone for the suggestions!

Any ideas on swivels? I have been looking at boat anchor swivels.

 

[ATH]

How about a Tire Swing Swivel?

 

[kzucas]

How about a Tire Swing Swivel?

What a novel concept.

No, actually the tire swing swivels look like they are made to be bolted to a beam and suspend the tire laying flat with 3 chains. I wont have a beam and I'm going for more of the classic look. Rope chocked around a tire hanging in the vertical position.

 

[ATH]

I know...I just did a quick Google search and saw that so had to post it. That is a lot less expensive than any swivel you will find from tree climbing catalogs. I wonder if you still couldn't use it though. What if you ran 2 eye lags into a 18" section of 4x4, fed the rope through those eyes, then bolted this onto the bottom of that 4x4??? You could still just hang a single rope from the swivel eye.

I just did a quick search at TreeStuff and Sherrill...
Here is the cheapest true swivel they have at $56: http://www.treestuff.com/store/catalog.asp?item=1762

 

[BC WetCoast]

I don't think you would need a swivel as the rope would twist giving the same effect. Also when you use a swivel, you prevent your kids from twisting the tire and rope into knots and getting the spinning tire ride.

The only additional advice I would give, is when you tie the rope to the lag hook (or whatever other device you decide to use) use a thimble so you don't get any premature rope wear as it rubs against the steel.

 

[Del_]

[


I wouldn't tie the two trees together with a horizontal line or cable. Wind storms would put incredible stress on such a line.


You could also do this with a single rope with each end tied to each tree using a stilson or cow hitch with an better half and girth hitch on the tire. The girth hitch on the tire could be adjusted easily to center up the swing. Move the rope every few years and no tree damage will result to the trees. It's a good idea anyway to have the install inspected for wear regularly. This is what I'd do and could have it rigged in an hour or so. Make sure the terminations on the trees are the same height.

Instead of girth hitching the tire two ropes ending with bowlines at the tires would allow for easy rope length adjustments.

If the climber called to do the job doesn't know the knots I'm suggesting, don't hire them. Any good arborist will know them.

 

[Jed1124]

@del and @ATH
You guys are ok with lags? I would think through bolting would be a much better idea. Constants stress could slow compartmentalization leading to decay, then failure of a lag. Just a thought. I through bolt all my cables for the same reason.

 

[kzucas]

Thanks again for the help everyone. Hit a busy time but I will definitely report back when I get it rigged up.

 

[Del_]

@del and @ATH
You guys are ok with lags? I would think through bolting would be a much better idea. Constants stress could slow compartmentalization leading to decay, then failure of a lag. Just a thought. I through bolt all my cables for the same reason.

I'm not fond of lags, see my edited post. I'd use rope around the tree as I suggested above. Through bolts would have to be really long and placed at the same angle the rope would be hanging. Going tree to tree is a bad idea due to wind stress which could result in incredible forces being generated. Rope about the tree inspected every two years. I'd like to see 9/16 or 5/8 rope used.

 

[kzucas]

[


I wouldn't tie the two trees together with a horizontal line or cable. Wind storms would put incredible stress on such a line.


You could also do this with a single rope with each end tied to each tree using a stilson or cow hitch with an better half and girth hitch on the tire. The girth hitch on the tire could be adjusted easily to center up the swing. Move the rope every few years and no tree damage will result to the trees. It's a good idea anyway to have the install inspected for wear regularly. This is what I'd do and could have it rigged in an hour or so. Make sure the terminations on the trees are the same height.





View attachment 505122

Those trees do move a lot in a good windstorm so this idea is appealing and not really anything I had considered. The 2 downsides for me are that it doesn't look you would get much spin. Maybe not a big deal but that classic wind up the rope and release acceleration is pretty fun... (Which I realize I wouldn't really have with a swivel either but you would get some spin). The other downside is I'm personally not a climber so I'd need to make sure I didn't get lazy about getting someone over every couple years to reset the rope around the tree. All in all I like it though.

 

[Jed1124]

OP, as a side note, the irrigation wetting the trunks of the trees could lead to problems down the road.

 

[kzucas]

OP, as a side note, the irrigation wetting the trunks of the trees could lead to problems down the road.

Good to know! Although I'm not sure how I could change it and still get good coverage without a pretty major sprinkler renovation.

 

[ATH]

I think lag bolts are better than wrapping around the trunk. They have a long history of holding. When installed with traditional cabling, there are still multi-directional forces pulling on them. I'd have no problem with a through bolt either... Most people don't have a drill bit that long, so for this purpose assuming the OP is doing it themselves I'd go with lags.

If slack is left in the line between the two trees as @ArtB suggested early on, it is effectively no different than what @Del_ is suggesting.

Let's say the trees are 15' apart. If the rope between them is 25' or 50' the impact on the rope and each tree is no different. If it is 2 ropes each 15' tied to a tire in the middle, again, they don't pull on each other more or less than a single rope that is 25' long with a single connection point in the middle. The only way it would matter is if the rope is trees try to sway further apart than the rope will let them go... If there is slack at the maximum sway distance it could be 3" of slack or 3 yards and it is still slack (minus the weight of the rope...but that is not enough to matter either).