Building a Zipline

Riding a Zip LineBuilding a zip line is a great summer project. It is both challenging and enjoyable to build, and when done safely provides hours of exciting fun for everyone. There are several ways to approach your project.  You can build it yourself, purchase a kit, or hire a zip line construction professional installer. Get advice from many sources including industry experts if you are at all unsure of what to do. The links and pages contained in this website do not constitute instruction, advice or guidance but are intended for general enjoyment as explained in the disclaimer.

Check your local zoning office and community covenants, conditions and restrictions (CC&Rs) to decide what approvals may be needed. Zoning applies to the type of use. CC&Rs apply to community standards. Permits apply to construction standards and safety. If any approval is needed prepare and present the zip line plans highlighting how you resolve any construction code or safety concerns. Check your city or county building office to gather facts and educate yourself on requirements in your area, then call your municipal building code authority to talk to an inspector about your plan.

If you are building a zip line yourself, here are some zip line equipment items you may consider. A cable puller winch will make tensioning your zip line so much easier. You'll likely be anchoring your zipline to trees. Here's a tree protector kit. Protect your trees from damage from to the zipline cable.

Zipline Construction Topics

Comment by: ZiplineSurviver
My friend Ethan and me and my friend made a Zip Line in a creek (my friends backyard really) and really it was NOT safe at all ... we just found a LONG rope and he was So stupid to grab a PLASTIC handle from a rake... the plastic melted and broke and he fell 30 ft into a dry ravine and broke his ankle, he had to have surgery too... But that was like 5 months ago and he's better now... DO NOT TRY TO MAKE A ZIPLINE WITHOUT THE PROPER MATERIAL!!!

Question Sent in by: ziplineplatform
I am building a zipline dismount from a treehouse platform, about 6' off the ground. The cable will be 35', attached to an 18" diameter tree at the low end. Can I loop pieces of cable around two smaller trees which support the platform, connect the two cables in the middle with a carabiner or quick-link, and attach the zipline to the carabiner or quick link--a three way split? The distance between the two smaller trees is ap. 5'. I'd like the starting point to be between the trees. At this point the users will be 50-60# 8 year olds, and the two smaller trees are ap. 8" and 10" in diameter. Thanks

Question Sent in by: zipkayak
Would a biner work on cable in the place of a pulley? Looking for a cheaper alternative to move a high volume of people through a zipline (and drop them in water) fast...

Reply: Steve
Absolutely Not. Metal on metal would wear through very quickly. This is unsafe and definitely not an option. Even some types of pulleys are not appropriate. You need double wheel in-line rollers built into the pulley to prevent the side-to-side twisting. These are called "trolleys" vs "pulleys", see zip line trolley. You are spending big bucks on aircraft cable and anchoring, harness, helmet, platform, etc, ... get a zip line trolley too.

Question Sent in by: Iredell
Will 5/16 telephone strand work for cable or must it be aircraft cable?

Reply: Gregg
I built a 160ft zip line with 1/4 inch aircraft cable, chain around the trees, heavy duty turnbuckles and connectors and a fusion trolley. Used a seat from my swing set and a carabiner to hook into the trolley. Very successful and lots of fun.

Question Sent in by: Brian
I have a possible zip line location stretching 650 feet across a canyon. Is this too far, using 3/8 7x19 GAC? Want to know before I go any farther in this project. any advice appreciated.

Reply: Steve
Check with an engineer on this question. The 100 ft kits use 1/4 and 3/8 inch cable, so I wouldn't be comfortable going beyond 100' with that size cable. Professional zip lines use 1/2 in cable or higher; and many of them have a backup cable the same size. This is especially important since you are going over a canyon; presumably a dangerous height. With greater distances the live load increases due to a variety of factors. The live load can spike over the cable limit, so it's not a matter of going by the published cable strength. You can contact one of the many zip line or canopy tour companies and ask for their engineering contact.

Comment by: Port Dover, Ontario
I built a 300 foot zip line from a tree to another tree across the field at my house. It's attached to a very thick pine tree and the cable passes over the garage roof 20 feet later, that's where you hook onto the line. It goes across the field to another maple tree. I didn't wrap the galvanized steel cable around the tree, I bolted it right through the tree. I used the block brake method because the zip line has a -0.1 slope and hits around 35 mph with an adult. Proper harnesses are used. Starting point is 30 feet above ground, garage roof is 20 (pull cable down with a rope and hook yourself on.). By far the best project I've ever done. Everyone loves it.

Question Sent in by: Marc
I am considering a zip line on my property. I am in need of a formula for the elevation change (slope) necessary between two terminals. I would like a formula where I could plug in the beginning elevation, cable size, zip line length, The live load, and percent cable sag to calculate what the ending elevation of the zip line needs to be to achieve a desired ending live load speed. I would appreciate it if someone could direct me to where I can find this or a similar formula.

Reply: Zipline Guru
In order to create a formula, you will also need to consider the bearing speed of the trolley and a number of environmental factors. It is best just to call and consult with an expert. Slope, tension, and load are just a few of the factors to consider. You must also include fall protection systems, risk management, platform design, braking, etc.
Reply: Steve
There are engineering books available with formulas, tension, endurance. Recommend you search or a library and have books shipped to your library to check out.

Question Sent in by: Ben
Hi! I was looking at setting up a zip line that crosses over a pond and you release into the pond for a swim. ... My concern is retrieving the handle back to the platform. So I'm looking for ideas and concepts on how I can achieve this. Any insight would be much appreciated.

Reply: Kevin
To return the zip line to the start, get a trolley designed for a zip line and have your finishing anchor on the other side of the pond. When you get out, or someone else wants to try it, just take the trolley off the line and reattach it at the starting point. I have built one of these and an option is to get a trolley with a return hook, then you can attach a string or rope to it and you can pull it back to the starting point.
Reply: Jacquelyn
You tie a line to the handle on your zip line and it has to be longer than your zipline. The rope stays tied by the launch area so you can wheel the handle pulley back from the beginning.
Reply: Freddy
You can rig up a couple of pullys and a counter weight that just ways more than the trolley empty. It will pull itself back when the rider lets go.

Sent in by: Charleston
Has anyone used rubber or plastic coated cable for their zipline. I failed to find this site before I purchased and strung up 130' feet of it. Why wouldn't this type cable work for a zipline?

Reply: George
I think the rubber coating or plastic coating on the cable would be soft and hinder the run of the trolley, and possibly get too hot.
Reply: dcavalie
Do not use coated cable. The reasons are that coatings inherently have a higher coefficient of friction. This will resist the pulley enough to warm up the coating which could result in the thermal breakdown of the coating matrix. At best, your ride would be slow. At worst, the coating would get soft enough to tear or shear and gum-up/clog the space between pulley and cable, or worse yet: heat the cable causing it to strain and lower it's cross sectional area enough that the stresses could cause it to break.
Reply: Zipline Guru
Coated cable should be used only in consultation with an engineer. There are many different type of coatings: some are jackets, others are plastic injected into the cable as it is spun. Coated cables can be very difficult to inspect and the wrong type can rust out and fail.
Reply: [none]
After a week of kids riding, the plastic coating slit and tangled up half way down.

Sent in by: Brendan
I'm looking for information or a website that can assist me in calculating the correct size cable for a 300' zip line run. Any referrals? Thanks, Brendan

Reply: Steve
Looks like these sites may have good info on cable size, length and strength; contact an expert in rigging to go over your plans and calculations.
Reply: Zipline Guru
The diameter of cable required depends on a number of factors including anticipated load from participants, wind shear, ice loading, tension applied to the cable, weight of the cable, and anticipated use.

Sent in by: Wesley
I am building a zip line in my back yard that will stretch about 70 feet. I have two trees that are large and about 10 feet apart. I am considering using the trees as the starting point but do not want to damage them as they are large oaks. How can I use the two of them as my starting point without damaging the trees?

Reply: Naomi
Protect the tree's bark with 2x4s vertically and spaced about 6" apart. This will distribute the force of the cable and let the cable draw into the 2x4 rather than into the bark.

Sent in by: Jose
I want to know if is better to do a zip line with to parallel wire ropes because in this case both wire ropes works decreasing the load and both are the backup of the other, is it right? or is better just one wire rope with a backup over this, thank you.

Reply: Geo
Either way I guess. It's good to have a backup especially if your zip line is fast, or high.

Sent in by: [annonymous]
I am building a zip line it is 100 ft I purchased a kit but we have too much sag in the line. We used 2 6x6x16 ft poles. We have not put guide wires in would this fix the problem?????? Is there any fear of the post falling over? They are in the ground 31/2 foot then cememnted with over 80 lbs of concrete each,??? Our ground is almost solid rock hence the 31/2 ft we were aiming for 4ft I want it to be safe for 6-9 year olds to use. HELP.

Reply: Z man
If you are unsure err on the side of caution and put in a guy wire to another 4' deep anchor on each end. To get the sag out, use a winch. You can pick up a small winch for under $20, capable of 600 pounds.

Question Sent in by: kip RUFFS DALE
I am building a 100 ft. zip line and would like too know if they make a trolley with a brake device because my grandson who is 6 yrs old will be using it with supervision.

Reply: Steve
I'm not aware of a trolley with a brake. Anyone else?

Reply: annonymous
The Alien Extreme Zip Line Trolley Kit uses a trigger brake built in to it. I don't know if you can buy the trolley separately.

Comment Sent in by: Mike
A great way to tension your cable. I drilled a hole in a piece of 4x4 about 10 inch long(of which is also my brake) it as two eye bolts attached. I put the 4x4 on the cable and attached a cable clamp as a stop. I purchased a 12v winch from Northern Tool with 30 feet of cable. (just $49.00 on sale Item# 141220) I strapped the winch to the tree ( it came with a bracket) and the cable hook to the eye bolts. I used a short strap to both sides of the 4x4 for an even pull. It was four times faster and much faster than my first try with a come-along and chain.

Comment Sent in by: Steve
I built a 280'zip line in my back yard 7/10/13 at first for one month it was the right speed. The wire is 3/8 aircraft galvanized. My trolly is a petzl tandem cable c e 0082 ( self lub bushing ) i built for smaller kids not weighing no more than 70 lbs. But recently, my 225 lb son went down. Ever since it has become slow, even after me tightening the cable again. Any advise will help. Best regards sg.

Comment Sent in by: annonymous
I recently built a zipline in our backyard. It is 3/8 inch steel wire and the connection to the upper tree is a loop with 4 uclamps and a second safety loop. The trees are protected with 2x4s with a groove to hold the wire. On the lower tree there is a turnbuckle (7200 lb rating) and a sling around the tree. I also have a back up safety cable from the turnbuckle around the tree for safety. There is probably a 9 foot drop between the trees and it is about 90 feet long. The top of the line is about 15 feet off the ground. It all seems safe in terms of the integrity of the cable, but it is a little too fast. The kids hit the brake (a water noodle taped to the line)about 4 feet above the turnbuckle at the bottom and their bodies flip up toward the line. I am wondering how to slow it down a bit or how to make the landing a little less abrupt. Without redoing the whole line that is.

Reply: Jorge
Either loosen the cable (add a little slack to the line), or raise the end a little and lower the start a little. Adding slack to the line, if possible, would be easiest. Also you could move the brake up the line a little so they start slowing down sooner.

Comment Sent in by: bgrayfields
My students are preparing a small zip line for competition and would like to know how to create friction so that it will stop on the target without dropping the object or causing damage.

Reply: David
There are a couple ways to slow it down at the end of the run. The best way is to have a little slack, or just enough slack, to create a slight "uphill" at the end of the line. Another way is to use a break block. A break block, which you can make or purchase. Another way to slow down is to run another rope at a right angle, under the line about 20 feet from the end. The line attached to the pulley will catch on this rope. Tie the rope to two trees on each side of the zipline.
Editor's note:Here's a link to some gear including a break block: Zipline Equipment

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