How to Build A Zip Line
Posted on March 23 2018
Whether you're looking to build a backyard zip line from yourself or you're thinking about buying a kit you first need to understand the basics. First and foremost you must decide how long you want your zip line to be, you'll need two sturdy anchors to accomplish this. (Most zip lines range between 100 to 200 feet.) Next you'll need to determine how much work you want to put in - DIY kits will allow you to more easily customize your zip line. You can choose your own trolley, length, and seat/harness. Complete zip line kits offer a similar flexibility, but many people tend to get nervous because the kits offer a fixed length - don't worry! If you have more than you need you can either wrap it around your anchor or cut it. Also, ALL of our zip line kits include 12 feet of additional cable to allow you an extra 6 feet of cable to wrap on either side of the zip line. To check out our kits look here:
Zip Line Cable Elevation and Slope
It is recommended that the zip line has at least 7-foot clearance over the entirety of the zip line terrain.
Use this formula: Subtract (A) the height of the sight level off the ground from (B) the height of the end anchor’s point off the ground to find (C) the elevation change of the ground. B-A=C
Zip Line Cable Sag
When testing the cable with a weight it should sag below the end anchor, and approximately 2% of the zip line’s total length. (don't worry it doesn't have to be perfect.)
The zip line cable should also have a 7 foot ground clearance as well.
Example: For a 100 foot zip line, the end of the cable would anchor 2 foot higher than the lowest point of the cable when a test weight is on the line. The minimum height on the ending anchor would be 9 foot to accommodate 7 foot ground clearance.To purchase zip line cable check out:
All tree anchors must be at least 12” thick in diameter. Only healthy, sturdy trees are suitable as anchors. Never attach cable to trees with excessive decay, cracks, exposed roots, diseases, excessive lean, lightning damage or poor tree architecture.
Free-standing poles (without guy-wires) must be 12” diameter, minimum. Poles must be sunk into ground at least 4’ or 2’ plus 10% of the pole’s height, whichever is greater.
Eyebolts that are used to terminate a zip line to a pole or tree must penetrate the anchor entirely in order to be secured with a washer and nut.
If the trolley does not mount freely on the cable, be sure to thread the cable through the trolley before terminating the zip line to the anchor.
Otherwise, the trolley wheels can be un-bolted to allow the trolley to assemble onto the cable.
If you are using a cable sling:
Wrap Cable Sling around Anchor. Pull up to designated height, create loop at open end of Cable Sling and adjust so loops of Sling meet at a distance half of the anchor’s diameter.
Clamp end of Cable Sling into small loop using Three Cable Clamps. Clamps should be spaced 1 to 2 inches apart and tightened with a wrench moderately past snug (≈30ft. lbs.)
Turnbuckles are used to adjust cable tension. While major adjustments require a winch and cable grab, the turnbuckles are useful for fine tuning.Turn the buckle to screw the shafts in or out. This often requires a bar or wrench, slid into the buckle, to leverage the rotation. Buy Turnbuckles
Turnbuckles are an essential component of most zip lines. Turnbuckles are primarily useful in adjusting zip line tension once your zip line is operational and the cable stretches from use.
It is recommended in the zip line industry to back up every turnbuckle with a cable and clamps.
Note: Turnbuckles extend the start of the zip line ride even further from the tree, so if your platform is too small, you may not have the space to safely mount on the cable.
Do not under any circumstances use chain link carabiners, only link attachments directly to trolley. Multiple carabiners can link to trolley. Do not put more than one attachment in a carabiner.
For any life support connections, (where the link is bearing the rider's weight) use a locking carabiner.
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