Suspension is an area that is frequently overlooked by first-time tiny house builders. Only after it is too late, too difficult and too expensive does it become apparent that the suspension needs to be looked at (usually after the first long distance trip). Today we’re going to pin down this bare-bones modification and wrestle through the pros and cons of air bag suspension for your tiny house.
Having recently driven my new tiny house canvas, a 4×4 Isuzu ex fire-truck, down from Central Queensland to Eastern Victoria (roughly 2700km). The need for a suspension upgrade became, literally, painfully obvious. The truck’s suspension consists of 4 packs of leaf springs about 300 millimeters thick. As you could imagine, 300 millimeters of steel doesn’t have much room for movement when it comes to softening the bumps of the wide open road. This can also be said for the vast majority of tiny house trailers, most trailers have leaf spring suspension without any other form of dampener, such as shock absorbers. Why does that matter? Well, leaf springs make for a notoriously rough ride. Whether your tiny house is on a trailer or a vehicle, leaf spring suspension ensures a far less comfortable ride, your possessions will find it difficult to remain in their place and the whole structure of your tiny house will be put under greater stresses. The solution to this problem? Air bag suspension.
For those of us who know little about air bag suspension, it is essentially an air bag, often with an inner coil spring, that sits above your leaf springs and underneath the chassis of your vehicle or trailer. When pumped up to the correct pressure, the air bag takes the load off the leaf springs and greatly increases the ride quality. It’s like driving on little clouds. After completing the trip home in the truck then installing air bag suspension I can tell you that it is an extremely wise investment, the comfort, and handling of the truck has drastically improved after the upgrade. Air bag suspension can also be used to level out your vehicle or trailer once parked. This is very handy if you find yourself in an area with no level ground. With the addition of a few control valves, you can individually pump of each air bag to achieve a level floor.
For this, there are a few suppliers in Australia. I used the air bag man, they supply generic kits for almost all applications. All you need to do is download a measurement sheet from their website or contact them and they will email the sheet to you. Print it off, take a few measurements of your undercarriage, fill out the sheet and send it back to them. They will put together a kit for you, complete with fitting instructions and post it out. The kits are incredibly straightforward to install, all that is required is to assemble the components, drill a few mounting holes through your chassis, then bolt it all together. In my case, I did have to modify one of the mounting brackets slightly because of a large amount of clearance between the diff and the chassis on our truck. This will not be necessary for most of you. Once installed the air bag suspension can be hooked up to an onboard compressor in a vehicle if one is available, or they can be pumped up to pressure by an external air compressor. Once they’re pumped up, that’s it.
This all sounds well and good, improved comfort and handling, safer possessions, less stress on your tiny house. But how much does it cost? The air bag suspension kit that I purchased for our truck cost around $3200. This seems expensive but this is a kit for a heavy vehicle. Lighter vehicles and trailers will be cheaper than that. So is it worth it? In my opinion, yes. Even if the air bag suspension kit had have cost $5000 I would have gone ahead with it. It’s important to keep in mind the amount of time you’ll be spending in your tiny house. Air bag suspension may seem like an unnecessary expense, but if you keep your tiny house for 15 years that works out at around $220 per year for a far improved suspension system that will also add resale value to your tiny house. I spend more on beer in a month than what it would cost per year for the upgrade.
If you do decide to upgrade your suspension to air bag suspension, it is a very good idea to do it BEFORE you start building your frame. The ability to get over, around and underneath your work area makes the job of installing air bag suspension much easier. For anyone who wishes to know more or ask any questions, please do not hesitate to contact me. Good luck and godspeed!