Step 1: Do an Inventory of Your Hardware
First, you want to make sure that you have all of the parts required for the install. You will need: aircraft cable, slings, cable clamps, a come along (if longer than 250'), a trolley, a turnbuckle, wooden blocks (to protect the trees), and some time and patience.
Slings are optional, as you can use a chain or you can simply wrap the zip line cable around the tree and then secure it with some cable clamps. You always want to install cable clamps in batches of 3 for maximum safety and security.
A come along will only be necessary if the ride is over 250', anything under 250 and you can simply use the turnbuckle to get the proper tension on the wire. If it's over 250', you will need a nylon sling wrapped around the tree which then gets attached to the come along, which then pulls the zip line cable taunt, allowing you to secure it with the proper hardware attachments (ie slings and cable clamps). This is all done on the high end of the ride, and the turnbuckle is used on the lower end. Once you have secured the high end of the cable with the cable clamps, you can remove the come along.
The wooden blocks are also known as tree savers. They are installed to help protect your trees and also to keep the tree from growing in around the zip line wire which would result in a hazardous situation.
The turnbuckle is used on the lower end of the zip line and is used to tighten the cable at the final stage to get it to the right tension. Don't forget to put the trolley on the zip line before you tighten up the wire...although most trolleys do separate and allow you to install them once the ride is up, it's sometimes easier to simply thread the zip line cable through the trolley prior to installation.
One final reminder, is to make sure that you purchase aircraft cable which supports the maximum rider weight that you intend to use with your zip line. You don't want to exceed the weight restrictions as this can end very badly, so please make sure that you triple check these numbers before purchasing your zip line.
That's it for step one, join us as we continue our installation in the next step, calculating ride length and height.
Step 2: Calculate Ride Length and Height
The first thing to do is determine the length of the ride. For this, you will want to use a simple tape measure or other measuring device. One of those rolling measuring wheels would probably be best (I forget what they're called). So you take two trees that look like they will be suitable for your ride, and measure between them to see what the distance is. You should already have a general idea of how long you want your zip line to be, so locating these trees in your yard shouldn't be hard.
Once you have measured your distance, find a zip line kit that supports a length a little bit greater than your measurement and place your order. For example, if your trees are 92' apart, you will want to buy a 100' zip line cable. Always round up, and leave some extra slack in the wire. You never want to round down and buy less or an exact length of cable relative to your measurement. For example, you don't want to have a 76' measurement and then buy a 75' zip line cable...Although you probably could get that to work with some long slings, it's best practice to always round up and leave yourself some wiggle room.
Now we want to calculate the proper height for the ride. As a rule of thumb, the best end height for a zip line is at 7', but this is prior to adjusting for cable sag. There is a 2% cable sag number that must be calculated into the overall length so if we are using a 100' zip line as an example, 100' x 2% = 2' so we must add 2' to the original 7' which will put our end point at 9'.
Now we have to figure out the overall drop for the ride which will be 6%. Using a 100' zip line cable, we multiply 100' x 6% = 6'. So we add 6' to our 9' which leaves us with 15' on the high end. So our zip line will be starting at a height of 15' and ending at 9'.
This completes the step of determining ride length and height. Now let's look at the next step where we figure out how to attach the zip line to the trees.
Step 3: Attaching the Cable to the Trees
Make sure that you use wooden blocks between the zip line cable and the tree to prevent the tree from growing around the zip line cable and messing up your ride in the future. You will also be using a turnbuckle and a thimble on the low end. The turnbuckle gets attached to the chain or sling, and a thimble is attached to the turnbuckle. Make sure your turnbuckle is fully extended, as we are going to be adjusting it later in order to apply more tension to the cable. Add your three cable clamps to the zip line cable about 3" apart to secure it to the thimble and move onto the high side, checking that everything is tight and secure.
Now it's time for the high side. Use your designated height and wrap the chain, sling, or zip line wire (or optional nylon sling with come along if over 250') around the tree and tighten up the cable. Get it as tight as you can by hand and secure it about 2 feet away from the tree with a cable clamp, using the U shaped part of the clamp on the side of the wire that doesn't have the tension on it. Now you can add the other 2 clamps evenly spaced in the section between your first clamp and the tree. Make sure everything is secure and now we can adjust the tension.
Now go back to the turnbuckle that we installed earlier and crank it down as far as you can, within reason, to get the zip line cable as tight as you possibly can. You may want to lubricate the threads on the turnbuckle to help things move a bit smoother. Once you have the cable to a tension that seems ideal, it's time to move onto the next step: Installing a brake block.
Step 4: Installing a Brake Block Kit (Optional)
Installing a brake block is a pretty basic procedure. Basically, you just need to attach the brake block to the zip line cable and secure the screws that hold the block together so that they are tight and secure. Next, hook up the bungee cord to the brake block with a carabiner, ensuring that it is connected properly. Finally, attach the bungee cord into the ground or a nearby tree, making sure it is taunt, so that when the trolley hits up against the block it will stop the rider.
Make sure that you attach the bungee cord away from the path of the actual zip line, to avoid collisions and entanglement throughout your ride.
Installing a brake block is an important step to your overall success when setting up your backyard zip line. Once you have completed this step, check to make sure everything is sound and secure, and then move on to the final step
Step 5: Testing Your Zip Line
Now, to test out the ride, attach the seat or harness and do a test run with just those items attached (not a human being). You can add a small amount of weight to the zip line to see how fast it will travel once you actually jump on it. This will also give you a good idea of whether or not you will need to install a brake block or not. Once you have made several test runs with just the trolley, now it's time to jump on it yourself. Do one last check to make sure that everything is tight and secure. Now let her rip! Have fun but be careful as sometimes the cable can drop suddenly if you didn't secure it tight enough. You may have to go back and add some extra support to the trees such as nails underneath the wooden brake blocks to keep the cable in position.
And that's basically it! You now have a working zip line kit setup in your own backyard! Please be responsible and remember to always wear the proper safety gear such as helmets and safety lanyards. Also, be shrewd as to who you let ride your zip line, as you don't want to be subject to any lawsuits. And that's all folks, thank you for reading and have a wonderful day!