Many RV manufacturers claim that independent trailer suspension provides the best ride. However, I will argue that it’s far from perfect when you look past the major marketing campaigns.
On the surface, it seems like an obvious upgrade that everyone should make to their rig. However, we believe that its not always the best option.
Today, we’re analyzing independent trailer suspension to see if it’s as good as people think. Buckle up; it’s going to be a bumpy ride!
What Is Independent Trailer Suspension
Independent trailer suspension is when each wheel has suspension components that are not connected to other wheels. This means there is no solid axle between opposing tires. You’ll find control arms, springs, and shock absorbers for each wheel, potentially even torsion bars and airbags. The result is a smoother and more comfortable ride, especially compared to solid axle and leaf spring suspension systems.
Independent suspension has become the standard type for most cars and light trucks because of its improved ride and handling. Independent suspension can also provide additional clearance between the vehicle and the ground because differentials and drivelines do not need to hang as low.
In these systems, each wheel responds to the bumps and changes in terrain independently. Reducing the transfer of force from movement to the vehicle. Generally, this is a premium or aftermarket upgrade for many vehicles and can be expensive. However, many owners enjoy the benefits and consider them worth the investment.
How Is Trailer Suspension Different From Vehicle Suspension
Despite both being suspension systems, trailer, and vehicle suspensions are very different. They both absorb impacts from the road and improve the ride. However, each has unique characteristics as their design and function are distinct.
You drive or steer vehicles, so vehicle suspension treats each wheel as a corner. A vehicle’s suspension absorbs the weight of the entire vehicle and acts together as one complete system.
On the other hand, trailer suspensions rely on tow vehicles to move them from point A to point B. As a result, the car absorbs some of the weight from the trailer. So independent suspensions are only somewhat independent. Unlike a vehicle with 4 points of control, a trailer really only has two, even if it has 4 tires. It needs to control side-to-side sway, but has no control over pivoting forward to back.
Another significant difference is that vehicle suspensions handle dynamic loads and forces. The weight in a vehicle constantly shifts, especially when accelerating, braking, or during sharp maneuvering. If you’ve ever slammed on your brakes, you’ve felt the dipping motion.
However, trailers are a more static load and rely on the vehicle’s ability to absorb the weight shifts. The demands for each type of vehicle are unique. These systems meet those demands to provide drivers and passengers with the best performance, safety, and ride quality.
Types of Independent Trailer Suspension
When considering independent trailer suspension options, there are many different geometries of how the suspension actually connects to the trailer. However, the general design allows for one wheel to move up and down on its own. This movement is defined by the spring type. There are a few different spring types, so let’s take a look at them and what their characteristics are.
Rubber has a natural dampening characteristic, which reduces bounce and helps create a smooth experience. However, for the same reason you buy new tires, the rubber wears out over time. It absorbs weight changes and impacts well but eventually needs replacing.
Another benefit of these systems is that they are generally lighter and require less space, especially compared to leaf springs. While it may not be a massive decrease, reducing weight can help increase fuel efficiency. Who doesn’t love getting the most MPGs?
Pro Tip: Before you upgrade your suspension system, discover Are MORryde RV Upgrades Worth It?
Coil-sprung independent suspension systems are the least complicated, longest-lasting, and cheapest options. They utilize a steel coil spring that attaches to the axle and frame. Like a Slinky, these expand and contract with bumps and changes in the terrain. Coil springs are the most common type you find on independent suspension cars.
Coil springs do not have any natural dampening, however. This means that they are prone to bouncing. The only way to combat this is to add shock absorbers that dampen the recoil.
Owners love these because they generally provide a comfortable ride and require minimal maintenance. They’re also incredibly durable and versatile. You’ll find them in different sizes and types of rigs. They’re widespread on off-road and heavy-duty trailers. CURT is one of the best options to consider for coil-sprung systems.
If you want a premium experience, you will need to pay a premium price. Air-sprung independent trailer suspension systems can provide the best possible experience. However, you’ll pay a pretty penny. Air sprung systems are some of the most expensive.
Air springs, or airbags, are less common on trailers. These systems use compressed air to absorb the trailer’s weight and impacts from the road. You can adjust them by the load and enjoy a smooth ride in various situations. Air springs also need shock absorbers to reduce bounce like coil springs, however the systems are adjustable. More air or less air can change the ride quality depending on the load you are carrying. These systems can also adjust the ride height of the trailer.
However, they’re very complex when you add the requirements of air compressors, tanks, and valves. You’ll add weight to your trailer, and it’s another piece of equipment requiring maintenance. Punctures and leaks can occur and result in expensive repairs. Two brands worth considering for this type of suspension are Timberen and Kelderman.
Claimed Benefits of Independent Suspension
Many owners choose independent suspension for its long list of benefits. The largest benefit is the improved ride quality due to the exaggerated movement they offer. More movement of the tires allows for a softer suspension that absorbs more impact. Improving suspension can help the trailer absorb these impacts, protecting the rig and its contents.
Another benefit drivers claim to love about independent suspension is its enhanced handling and stability. Much of this benefit is from the same additional wheel travel and requirement to have shock absorbers at each wheel. This helps control the recoil and keep wheels in contact with the road.
Some drivers claim independent suspension systems increase fuel economy. This may be slightly true in some systems, especially compared to solid axles and leaf spring systems. However, there are various factors to consider regarding fuel efficiency. You may notice a slight increase in efficiency but don’t expect a significant improvement.
Known Drawbacks to Independent Suspension
While several benefits make independent suspension an excellent choice, some drawbacks exist. To make an informed decision, it’s crucial that you also consider the negative aspects.
Generally, these can be more complex systems that require more maintenance. So not only will you have to pay a premium to install them, you’ll need to stay on top of maintenance. Wheel alignments are notoriously harder with independent suspension and are more likely to get knocked out of spec. In addition, rubber or air-suspended systems require part replacement occasionally. Some are also heavier, which can reduce your payload and fuel efficiency and increase trailer sway.
Installing these components on your rig could require more ground clearance. This could raise your trailer’s height by an inch or two. If you’re worried about low clearances, these systems won’t ease your concerns.
While theses are all downsides, there is one major problem that many people ignore with multi axle independent trailer suspension.
Pro Tip: Use our Ultimate Guide to Trailer Suspension Types and Upgrades to decide what is right for your rig.
The Multi-Axle Mistake
Independent trailer suspension may be a game-changer 4 wheel cars. However, you could be making a significant mistake if you use it on a trailer with multiple axles. The purpose of multiple axles on trailers is to increase the weight-carrying capacity of the trailer. In traditional multi-axle trailers, equalizers are used between the tires to distribute the weight as the trailer goes over bumps to maintain equal pressure. However, in independent suspension, equalizers are rarely installed. The weight distribution shifts on uneven surfaces as the suspension absorbs the changes. You can’t make this weight disappear. So where does it go?
In independent suspension systems, as a tire takes more force due to a bump or angle change in the road, it takes more of the weight and does not distribute it. The problem here is that this tire can quickly become overloaded. In fact, we have seen independent suspension systems that completely lift extra trailer tires off the ground. This means that the loaded tire is taking 2x the weight! In an equalized system, this should not happen.
This can overload the tires and cause increased wear and tear. Unfortunately, this could elevate your chances of a tire failure or mechanical failure, which can be a horrific experience. Unfonrtauntly this is not just an assumption because we have seen and repaired physical damage from overloads on multiple IS systems in person.
The solution to this problem is to use equalization on multi-wheel independent suspension systems. One common way this is done with heavy trailers or multi-axle trucks is to use a walking beam suspension. This provides the movement of IS suspension with the equalization of traditional solid axles. Another way this can be accomplished is with airbags that are tied together. Allowing the air to move between axles can act like an equalizer. Unfortunately, we are unaware of anyone offering this type of suspension for smaller trailer use.
If you choose to install IS suspension on multi-axle trailers without equalization, make sure the tires are over rated as well as the axle weight capacity. If they are not, know that regular overloading will wear things out and can even do frame damage.
Best Multi Axle Trailer Suspension
When it comes to the best multi-axle trailer suspensions, the best designs use walking beam suspension or tie airbags together to act as an equalizer. Unfortunately, these are typically only on higher-end industrial-use trailers.
The best options are leaf-sprung systems with additional damping in the equalizers and shock absorbers. This is a relatively cheap and effective method that provides a smooth experience. MORryde is one of the biggest names in this market, both in equalizers and IS. Many in the RV community trust them, but it doesn’t hurt to add some damping with shock absorbers.
Personally, we ran a trailer with MORryde rubber equalizers and stiff shock absorbers for over 100k miles. We compared it extensively to the MORryde IS system and decided our ride quality was similar enough that keeping the equalization was worth it.
When Is Independent Trailer Suspension Best
We’re not saying that independent trailer suspension isn’t a suitable option. However, many consumers upgrade when they don’t need to. Independent trailer suspension is a fantastic option for small, lightweight, single-axle campers. If you enjoy taking your rig on off-road adventures, you’ll notice the benefits even more.
Independent trailer suspension has some useful benefits but is not always the best. You must do your research and consider all your options. You can achieve the same results at a fraction of the cost. We want you to have the best possible experience on the road but not waste money.
Do you plan to upgrade to independent suspension? Tell us your thoughts in the comments!
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