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How to Build a Zip Line

Aaron Roper
posted this on March 13, 2013, 12:15 PM

How to build a zip line

Setting up your first zip line? Let us help take any uncertainty out of the project and get you up to speed on the basics of how to build a zip line!

Please note that you are responsible for your use of any advice and instruction. Any advice, written or spoken, is not a guarantee of safety from Sleaddventures, LLC dba Zip Line Gear.

Site Selection

Prior to installing your zip line, select an appropriate location. Clear runway for your zip line with a sturdy anchor on both ends, and allow enough slope in the cable to propel your participants from one end to the other. Although there are relatively few locations where a zip line cannot be installed, some locations will provide for a safer and more enjoyable ride than others. Typically zip lines are installed between two trees at least 12” in diameter. Finally, select a site that will allow you to build a 6% slope into your zip line cable. You will also need to account for an additional 2% of sag with a rider on the zip line. See the diagram below.


Check out our full guide on zip line site selection.

Choosing your zip line equipment

After determining your zip line site and applicable slope, you will need the appropriate zip line equipment. Your equipment needs will vary depending on the length of your zip line run and its height above the ground. The following kits are an excellent fit for zip lines of 200' or less in length: 


Viper Zip Line Kit


Viper Deluxe Zip Line Kit

For zip lines over 200’ in length, look for a kit similar to the QuickSilver Zip Line Kit.


Or, you can build your own zip line kit.

If your zip line height above the ground will be a distance that could result in injury after an accidental fall then you will need to purchase a zip line harness. If your zip line height is lower to the ground then your zip line riders can enjoy their exciting ride on a handlebar or a Cobra Zip Line Seat.

Check out our handy guide on buying attachments and accessories for your zip line.


Depending on which kit you purchase, the installation on your zip line will vary. In either case you will most likely need to use a Zip Line Tensioning Kit. This handy device is a life-saver when it comes to set-up and install. Best of all it is returnable after use for a 100% refund.


Your first step will be to set the main cable by extending both turnbuckles and attaching them to your anchors with the cable slings. You will be stretching the cable from one turnbuckle to the other (if you have 2 turnbuckles in use, otherwise see the Viper Zip Line Kit Installation).

Step A: Attach the looped end of your main cable to the turnbuckle on which ever end is least accessible.

Step B: Unwind your cable to the opposite end, pull it as tight as possible (by hand), and attach your come-along or tensioning device to the cable via the cable grab.

Step C: Crank your tensioning device until the cable hangs near the desired height.

Step D: Bring up the slack end of the cable, and fix it to the other turnbuckle using your cable clamps and thimble as shown in the diagram below. Position the clamps so the U-bolt is against the folded-back end of the cable.

These steps are modified and pulled from our QuickSilver Zip Line Kit Installation Manual. You can find all of our zip line kit installation manuals below:

QuickSilver Zip Line Kit Installation Manual

Viper Zip Line Kit Installation Manual

Bungee Brake Installation

Most zip line kits will have a Boa Bungee Brake Kit in the package. These brakes are pretty simple to install.

Your bungee stop is installed near the end of your zip line to catch the pulley and slow it down to a stop. The block should be bolted together around the cable, with the rubber pad facing the top of the ride. The 30’ bungee cord then runs from the block to the anchor lag screw, which can be screwed into a nearby tree or post (use the 3/8” quick links to connect the bungee cord to the anchor and the block). The bungee cord has a safe stretch limit of 175%, so make sure the cord is NOT stretching to more than 50’ when riders are hitting the brake. If you are stretching it longer than 50’, try doubling the bungee back so that you have two 15’ cords providing increased resistance, and make sure these are not stretching past 25’ in length. If you are still over extending your bungee, you will need to purchase more bungee cord or decrease the slope of your zip line.

Assemble your riding equipment

Most zip line kits will come with a few components to assemble together for each rider. The trolley will typically be removable from the zip line, except for the Viper which is made to stay on the zip line. This trolley will have various attachments that can lock on it via carabiners, such as handlebars, seats, and harnesses.

Test your new zip line

Weight Test: The weight test should be done at the center of the zip line with at least 350lbs of load (hang a rope from the pulley and have two adults bounce their weight on it). Then check/retighten all cable clamps, bungee block bolts, and turnbuckles. Never exceed 350lbs in the actual operation of the zip line.

Speed Test: Have a test rider sit on the seat, and lower them down the zip line by walking or running alongside them holding a rope attached to the pulley. Increase the speed of each run until you are confident that the zip line will not be too fast or over extend the bungee brake if the riders are allowed to zip freely. Once accomplished, your zip line is ready to roll!

© Zip Line Gear 2013


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