Class B Motorhome Suspension

Class B Motorhome Suspension Q&A

T.J. Product Information 4 Comments

We recently communicated with a group of Class B coach owners/enthusiasts. They asked a handful of great questions related to Class B suspension improvements. These owners love their Class B’s, sometimes referred to as van conversions, for their ability to get into smaller spaces, take tighter turns, and their car-like driving experience. In this blog post, I will share some of the questions we discussed.

I spent a lot of money on this coach, doesn’t it have good suspension?

Yes. You do have good suspension. The suspension on your Class B is almost always the original equipment installed on the van’s chassis, most popularly: the Mercedes Sprinter, Ford Transit, or Dodge RAM ProMaster. The reason you consider a suspension enhancement is to improve ride quality. The original suspension was chosen not based on the fact you drive a Class B motorhome. It was selected because the manufacturer expects the van to be used in various commercial and recreational applications. The springs utilized are deemed appropriate for all. As you add weight (as did the manufacturer of your coach), cargo, water, people, etc., a raised roof, and other unique characteristics to a Class B RV, SumoSprings enhance your suspension (not replace it), to help stabilize the coach, dampen road vibration, and level sag, improving the ride quality you expect from a Class B.

Here is an analogy. You buy an iPad to take with you on your Class B adventures. The iPad works great just the way it is out of the box. You buy some enhancements; not because the iPad is inadequate, but because the enhancements improve the iPad based on your wants and needs: a case, because you may take it outdoors while camping; a screen protector, because you are clumsy and tend to drop things; a Bluetooth speaker, because you like to rock out; you download an app, because you like to play games. It is not that the iPad “needed” these improvements/enhancements; the improvements made the iPad a better product for your personal wants and needs, for how you use the product. The same is true for SumoSprings. We are not replacing the original equipment; adding SumoSprings compliments and improves your Class B van for how you personally use it.

SumoSprings are not springs. Why do you call them springs?

SumoSprings are springs! They are pneumatic “air” springs. Class B owners, as was shared with me by this group of enthusiasts, are calling SumoSprings, “sponges.” I like the name sponge, because SumoSprings do have unique damping properties, but “SumoSponge” sounded like a kitchen accessory or over-sized aquatic invertebrate, not a suspension enhancement. The name spring caused some confusion among this group with owners thinking they were replacing the springs. The rear of the Class B Winnebago Travato – a coach built on a Dodge RAM ProMaster 3500 chassis – for example, has a leaf spring assembly for rear suspension. We are not replacing the leaf spring assembly. Instead, SumoSprings replace the factory bump stop, and fill the void between the frame and axle. We are placing a second spring (the SumoSprings) between the frame and existing spring (the leaf springs). The original bump stop is not part of your suspension. It is not designed to be engaged/loaded. The bump stop is there to prevent metal on metal contact (the frame and axle), which could result is catastrophic failure, bending, breaking, etc. The bump stop is a preventative accessory. SumoSprings are an active part of your suspension, intended to be pre-loaded and engaged. SumoSprings have a progressive spring rate, meaning, as they compress more, they resist more. This means smooth engagement, reduced sway, and a more stable ride. Some owners have described the feeling as having a combination of sway bars and shock absorbers – all for a fraction of the cost! When a more conventional spring (coil spring, elliptical spring, even a rubber spring) is compressed, it releases that energy in what is called rebound. In suspension, this is not a desired characteristic as it results in bounce, hop, and porpoising. When SumoSprings compress, they dampen, they absorb and dissipate the energy so there is no excessive rebound. So, to answer the question, we call them springs because they are springs. But, we like you calling them sponges because they do soak up shock and energy unlike other springs!

Will SumoSprings lift my coach?

SumoSprings are not a lift kit, and are not designed to lift your coach. However, most Class B vans have a lot of weight on them, causing them to unknowingly (in some cases, obviously) sag. SumoSprings, as mentioned above, are springs! They will resist when compressed. By placing SumoSprings in the void between your coach’s frame and axle, SumoSprings bear some of the weight, eliminating some of the sag. Some owners reported a 2″ lift in their Class B vans after installing SumoSprings. It is not a 2″ lift the SumoSprings induced, it is actually 2″ of sag the SumoSprings eliminated. This helps level your coach. Therefore, your vans center of gravity is brought back to what the manufacturer intended, your driving experience is more stable, you do not need to fight the steering wheel in unfavorable road conditions, and you and your passengers are safer than you were without SumoSprings.

There was a follow up question, “should I adjust my headlights or get my alignment checked after installing SumoSprings?” The safest answer is to ask a professional, but the short answer is “no.” SumoSprings are not lifting your van, they are leveling your van, and your headlights were installed with a level van in mind/design. Unless your coach is out of alignment due to other factors, there is no reason to realign your van after SumoSprings.

What color/density is best for a Class B?

SumoSprings come in various densities, also referred to as durometer, grade, or light|medium|heavy duty. This question is common for all SumoSprings’ applications. The answer is twofold. One, what is the vehicle being used for? Commercial applications almost always carry a lot of weight, and therefore a heavy-duty material is recommended. Class B coaches do carry a lot of weight, but drivers tend to want improved ride quality over load carrying ability. So, a medium -47 (black) or -54 (yellow) are both acceptable. Therefore, two, it comes down to personal preference. If you have ever driven an American muscle car in comparison to a German sports car, you may be familiar with comments like “the American muscle felt loose,” or “the German sport felt tight.” It is personal preference in most Class B applications. Statistically speaking, for the front, the -40 SumoSprings and/or Coil SumoSprings are most popular. For the rear of 2500 series vans, without anything in tow, the -47 SumoSprings are most popular. For 3500 series vans, the -54 SumoSprings are most popular. In some instances, SuperSprings are used, but that is a different conversation.

Comments 4

  1. When I called your company about the difference between the -47 and -54 springs I was told they both improve ride control but if you are carrying a heavier load the heavy duty (yellow) ones are better. I went with the -47 units but after reading this I’m wondering if I would have achieved even better ride control with the -54 units. This is quite frankly a bit confusing and I’m wondering if I wasted my money and time.

    1. Post
      Author

      Hi Steve, thanks for the comment. This post generalizes all Class B applications. A Sprinter is very different from a ProMaster, and it is therefore hard to generalize between the two. I apologize if my attempt to do so confused you. If you spoke with one of our customer support representatives, no doubt in my mind they gave you good advise. I have recommended -47 springs to numerous Class B owners and every single time I get a call or email from the customer sharing how much they love SumoSprings. If that is not your experience, we will work with you to make sure you are happy and your ride quality is improved to your expectations. Please feel free to send me an email or call so we can discuss. https://www.supersprings.com/contact

    1. Post
      Author

      Thanks for the question, Lee. Yes. SumoSprings can be used on a RAM 5500 pickup. With that size truck/trailer combination, I would recommend three things. First, instead of SumoSprings Solo by themselves, I would use SuperSprings with the SumoSprings. The SuperSprings will help level and stabilize your truck. The SumoSprings will be like a secondary spring to help reduce sway and dampen road vibration/shock. Lastly, adding SumoSprings to the trailer axles/spring packs, Trailer SumoSprings, will help stabilize the ride, but more importantly, protect your trailer components and take some of the stress off your trailer’s leaf spring assemblies. Give our tech line a call so we can get more details about your truck and trailer, to help make a solid recommendation on part numbers.

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