Introduction

Today we are looking at the Buckingham System - what it is, how to use it, information on gear selection, methods for keeping gear in good shape, and tips and tricks to get the most out of your system.

Overview

First, let's talk about what exactly is the "Buckingham System".

The Buckingham System is a very simple tensioning system for slacklines and highlines, discovered by Thomas Buckingham, President of the International Slackline Association. Essentially it is a system in which you can tension your slackline using the slackline itself, plus a few other pieces of gear. It results in a very simple mechanical advantage system that allows you to tension your line to a reasonable tension without much effort or cost.

There are several ways to rig a Buckingham system, each with their pros and cons. In this article and video, we will be looking at 3 main types of Buckingham Systems:

• Simple 3:1 Buckingham System
• Compound 5:1 Buckingham System
• 9:1 Buckingham System

Gear Selection

Before we go into depth on each of these 3 systems, let's take a look at the specific gear needed for all of these systems. There are 3 basic components in a Buckingham System:

• Webbing Anchor (Weblock)
• Roller (webbing pulley)
• Webbing Grip

Webbing Anchor

For the webbing anchor, aka weblock, the only requirement is that you are able to pull slack through the device by pulling on the tail coming out of the device. Most modern weblocks have this feature, so not much to worry about here.

Another thing to keep in mind with your weblock, which is generally important for rigging slacklines (particularly those that are at heights), you need to have the width of the weblock match the width of your webbing. If that is not the case, you need to install spacers in your weblock. To have the weblock function properly, it is imperative that you have no gaps between the edges of your webbing and the walls of the weblock (or spacer).

Roller

This device can be a webbing roller carabiner, or a pulley designed for webbing. The most important thing about this piece of gear in this system is that there is a smooth surface for the webbing to travel over as you tension. There will be a lot of movement at this location, so having a smooth surface is critical. What's also helpful is having the pulley be high efficiency, in order to have the least amount of friction while tensioning.

Webbing Grip

The webbing grip, aka Linegrip or Wafer, is arguably the most important piece of gear in this system. It is also the piece of gear with the most restrictions when it comes to your specific setup. Which grip you choose depends on 3 main factors:

• Webbing Width
• Base Mechanical Advantage
• Number of people pulling

There are 2 main classifications of webbing grips: full-size and micro. Full-size grips are webbing grips that are the same or close to the same size as the original Linegrip. Examples of full-size grips are the Wafer XL and the LineGrip (both use the same size rubber plates). A micro grip is a webbing grip that is smaller than a full-size. These styles come in a variety of sizes, each with their own thresholds for slippage. An example of a micro grip is the Wafer and Wafer 2.0.

To make things as simple as possible, Buckingham Systems should almost always use a full-size webbing grip in order to reduce the chance of slippage. Webbing grips are inherently prone to slippage based on how they grab onto the webbing. The majority of webbing grips on the market at this point in time rely on friction to grab onto the webbing. Most of them do this by squeezing the webbing between 2 rubber plates. The squeezing is increased with tension on the grip itself. There are many factors that can impact the reliability of this friction grip: humidity, temperature, direct sunlight, material of the webbing, weave of the webbing, age of the rubber, age/wear on the webbing, etc... For this reason, we want to opt for the device that gives us the biggest margin of safety for tensioning our lines. Often times we put more force on the grip than we realize, which pushes us closer to that slippage threshold.

There is really only 1 situation where a micro grip is acceptable to use as the main webbing grip in your Buckingham System: 1 person pulling tension on a Simple 3:1 Buckingham System on a 1-inch (25mm) webbing. Any deviations from that should opt for a full-size grip.

Pre-Setup

Before we dive into the setup of the Buckingham Systems, we should first look at an important factor with the webbing anchor. Depending on how you plan to pull tension on your slackline, the orientation of your webbing anchor is very important. You want to position the tail of your webbing leaving the weblock on the correct side of the line (either top or bottom). If you will be tensioning your slackline mainly from below the line (your line sits above you while you pull tension), then you will want to setup your webbing anchor right-side-up. If instead, you plan to tension your line from above the line (for example, on a highline with the anchor on the ground at the edge of a cliff), you will want to setup the webbing anchor upside-down as this will leave the tail of the webbing coming out the top of the device.

This orientation is very important for getting the most out of your tensioning system by limiting friction caused by twisting of the strands while tensioning and also prevent twists in the webbing from entering the webbing anchor as you pull.

This same caveat applies to your webbing grip as well. Make sure the anchor point where you will attach your roller to the grip is on the same side of the webbing as the tail leaving your weblock. So if your weblock has the tail on the bottom, the webbing grip anchor point should be on the bottom of your line as well.

Simple 3:1 Buckingham System

Now let's take a more focused look at the simple 3:1 Buckingham System. This is the most common way highlines are tensioned in modern day slacklining. This method is by far the easiest to setup, easiest to operate, and least gear intensive of the 3 methods. Here are the gear items you will need:

• 1x Webbing Anchor (Weblock)
• 1x Roller (webbing pulley)
• 1x Webbing Grip

Install your webbing grip on the slackline just in front of the weblock with the anchor point facing the weblock. Clip your roller to that anchor point and run the tail of the webbing coming from the weblock through that roller and then back towards the slackline anchor.

This system results in a theoretical 3:1 mechanical advantage. What that means is that every unit of force you apply to the tail of the webbing when you pull is tripled to the slackline (and webbing grip). For example, if you pull 0.5 kN on the tail of webbing, you will be applying 1.5 kN to the slackline. This, of course, does not account for friction in the system, which there is quite a lot. Even with this friction, it is entirely possible for most people to achieve 1.5 - 2.0 kN of tension using this system when pulling by themselves.

Speaking about the friction, most modern weblocks rely on friction to function properly. The Buckingham System, in general, works to overcome this friction to tension the slackline, then relies on it again to hold the tension once the desired tightness is achieved. It's a great feature of weblocks, but works against us when we want our lines tight. The 3:1 system suffers quite a bit from this friction loss as all the strands within the pulley system are impacted by it.

• Base Mechanical Advantage (Theoretical) - 3:1
• Max tension with 1 person pulling - ~ 2.0 kN

5:1 Compound Buckingham System

Moving on to the next version, we have the 5:1 Compound Buckingham System. This system is a great way to increase your pulling power without adding too many more components to the system. You will only need 2 additional gear items to nearly double your theoretical pulling power (almost certainly do double it in real mechanical advantage terms). This system relies on a separate 2:1 system being built out of a short piece of rope. Here are the gear items you will need:

• 1x Webbing Anchor (Weblock)
• 1x Roller (webbing pulley)
• 1x Full-Size Webbing Grip
• 1x 2-3 meter long super low-stretch rope (Dyneema rope with spliced eyes on each end works well)
• 1x rope pulley (or second roller)

First, find a place behind the weblock to anchor the short piece of rope. You can share the anchor with the weblock or use a separate one. You will have more efficient pulling power if you share the anchor with the weblock as you will not have any of your effort going into making the anchor tight. Install your webbing grip on the slackline just in front of the weblock with the anchor point facing the weblock. Clip your rope pulley to the webbing grip and run the short rope through that pulley. On the other end of that rope, clip your roller. Now take the tail coming out of your weblock and run it through the roller and back towards the slackline anchor.

This system results in a theoretical 5:1 mechanical advantage. What that means is that every unit of force you apply to the tail of the webbing when you pull is multiplied by 5 to the slackline (and webbing grip). For example, if you pull 0.5 kN on the tail of webbing, you will be applying 2.5 kN to the slackline. This, of course, does not account for friction in the system. Due to the way this system is setup, less material is subject to the great friction that is caused by the weblock. The 2 strands made from the rope are entirely free of this friction, and that is a big source of the pulling power. You will notice immediately how much easier it is to apply higher tensions on your line with this system.

• Base Mechanical Advantage (Theoretical) - 5:1
• Max tension with 1 person pulling - ~ 4.0 kN

9:1 Buckingham System

Moving on to the next version, we have the 9:1 Buckingham System. This is the most complicated and gear-heavy version of the Buckingham System. You are essentially multiplying the Simple 3:1 Buckingham System with another 3:1 system, resulting in a 9:1 mechanical advantage. Here are the gear items you will need:

• 1x Webbing Anchor (Weblock)
• 3x Roller (webbing pulley)
• 2x Webbing Grip (with at least one being full-sized)

Install your full-size webbing grip on the slackline just in front of the weblock with the anchor point facing the weblock. Clip one roller to the webbing grip and run the tail of the webbing leaving the weblock through this roller. On the tail leaving this roller, install your second webbing grip with the anchor point facing the weblock as well. Clip the second roller to this webbing grip. Now find a place on or behind the weblock to clip the third roller. By the same reasoning as above, you should try and share the anchor with the weblock to prevent extra effort from being exerted while tensioning to get that anchor tight. Now run the tail of the webbing through the roller at the anchor and then back to the second webbing grip and through the roller connected to it, then take the tail back towards the slackline anchor.

This system results in a theoretical 9:1 mechanical advantage. What that means is that every unit of force you apply to the tail of the webbing when you pull is multiplied by 9 to the slackline (and webbing grip). For example, if you pull 0.5 kN on the tail of webbing, you will be applying 4.5 kN to the slackline. This, of course, does not account for friction in the system. This system having the majority of the mechanical advantage behind the weblock, will see a ton of loss from the friction within the weblock. Out of the three methods listed here, the actual mechanical advantage you get will be the furthest from the theoretical mechanical advantage. This, coupled with the high gear need, makes it hard to recommend this system unless you are in a pinch and need a lot of force in your line with limited pulling power.

• Base Mechanical Advantage (Theoretical) - 9:1
• Max tension with 1 person pulling - ~ 5.0 kN

Pre-Pulling Checks

The Buckingham Systems have some inherent dangers to them as you are using the slackline itself to tension the slackline. In order for the systems to work, the webbing has to travel through the weblock and 1 or more pulleys. These points of redirection are sources where your webbing and hardware can easily be damaged, particularly when there is a large force being applied to the tail (i.e. multiple people pulling). Also, as we discussed above with the webbing grip selection, friction is being relied upon to put a great deal of force on your slackline. If a grip slips, or the webbing is misaligned in the weblock or rollers/pulleys, you can inflict a great deal of damage to your walking line. So, to prevent this from happening, there are some very simple and effective steps you can take before pulling tension on your line:

Weblock Webbing Alignment

This is a step that should be taken prior to any tensioning system being setup on the line as it will be difficult to change once any tension is on the line. Ensure your webbing is running through your weblock without any twists or misalignments within the device. This will ensure the webbing travels through the weblock smoothly and efficiently, adding to your real mechanical advantage while tensioning.

Webbing Grip Engagement

Modern Webbing Grips can be very good at holding onto webbing up to very high forces. However, sometimes the initial grip is unreliable. There are a multitude of reasons why this happens, but it is very easy to fix. When you position your webbing grip on your slackline, you should always give a strong tug on it to engage the rubber onto the webbing. I like to pull hard on the anchor sling of the grip towards the slackline anchor. Then once I tug on the sling, I will keep tension on the tail of the slackline to keep the rubber engaged. This will ensure a reliable grip every single time. This should be done with every reset of the grip as well as every time you install the grip on the webbing.

Failure to set the grip prior to pulling hard on the tail of webbing (or pulling hard with a separate pulley system) can and has resulted in major slippage on the slackline. This type of slippage can completely ruin your slackline webbing, even with the first usage. It's imperative that you set the grip prior to applying tension to it. Also, keep an eye on the grip while tensioning to ensure the setting actually worked and you aren't experiencing any slippage as you apply tension.

Roller Webbing Alignment

This is another common mistake that has lead to catastrophic damage to slackline webbings. If the webbing is misaligned in the roller before tensioning, it can pass over a non-ideal part of the roller and tear the slackline webbing (particularly when multiple people are pulling on the line). This is also a very easy fix with a simple technique change. Similar to the grip strategy above, align the webbing properly in all the rollers in your system, then hold a light tension on the tail to keep that alignment. Keep holding this tension even between tugs so that there is no chance the webbing can become misaligned while tensioning.

With proper pre-pulling checks and continuous awareness of potential issues that can arise while using the Buckingham Systems, these tensioning methods can be very effective at getting your slackline tight in a safe and reliable manner. However, there is the possibility of damaging your gear very quickly if attention is lost or checks are not being done. For the sake of the longevity of your gear and safety of yourself and friends, these pre-pulling checks are a great habit to get into.

Pulling

Each of the above Buckingham Systems have their quirks with the actual pulling. Most notably, the 5:1 Compound and 9:1 systems will require several resets of the primary and secondary (in the case of the 9:1) grips. Just keep in mind the pre-pulling checks above with every reset of either grip.

The best strategy for a smooth tensioning process is slow and steady pulling rather than fast and jerky pulling. A slow and steady pull will gradually increase the grip on the webbing grip, making it more reliable at holding higher forces.

In general, having more friends pulling instead of adding more pulleys is a great way to go for increasing the tension in the line. However, at some point (beyond 3 people), the better solution is to use a proper pulley system separate from the slackline itself. As we discussed above, there is a ton of friction inside the webbing anchors. When forces start to increase, that friction in the webbing anchor can start to cause harm to our slackline webbings if using a Buckingham System. So, if you plan to have more than 3 people pulling on a 3:1 or more than 2 people on a 5:1 or 9:1, you should consider switching to a full pulley system that does not rely on pulling the webbing through the webbing anchor.

Keep in mind that every one of these systems is a way to multiply the power you are able to exert onto your slackline through the use of mechanical advantage. With that multiplied power, there is great potential energy being stored in your system. By performing the pre-pulling checks and following the above tensioning tips, we can lower the probability of turning that potential energy into kinetic energy.

Thank you for taking the time to read this article or watch the video. If you have any questions or comments, please feel free to reach out to us directly.