RV Suspension and Alignment

How RV Leaf Spring Suspensions Work

There are various suspension systems used on RV trailers with the most common being the leaf spring or "buggy" spring system. This worked well in the horse and buggy days and is a carry over from that time. It is referred to as a leaf spring because there are several slender sections layered upon each other to provide the required stiffness or load carrying capacity while at the same time being flexible enough to absorb the shocks of road travel.

Either end of the main leaf spring is attached to a spring hanger on a single axle trailer or to a spring hanger and an equalizer on a tandem axle setup. Factory steel equalizers transfer a lot of harsh road shock. Upgrading to a rubber-cushioned equalizer (like the MORryde CRE3000 or Dexter E-Z Flex) absorbs that impact before it reaches your trailer frame.

The Problem with Factory Nylon Bushings

The ends of the springs are rounded into an eye shape to allow them to be mounted onto a bolt and each point must be able to pivot around that bolt. A plastic or nylon bushing (see replacing bushings ) is inserted in every pivoting point on the suspension system to take the wear and tear on these parts.

These factory nylon bushings are notoriously cheap and often wear through quickly, allowing more "sloppiness" in the suspension. Instead of replacing factory nylon with more nylon, most RVers upgrade to a Heavy-Duty Wet Bolt and Bronze Bushing Kit. These kits use greasable bolts and brass sleeves that outlast the trailer.

The weight of the coach is carried by the ends of the springs and the center of the spring is bolted to the trailer axle which, of course, is attached to the wheels and tires. This whole arrangement provides a smooth ride for the trailer, with the springs absorbing the unevenness of the road surface. Further dampening of road bumps is provided by the use of shock absorbers.

Reading Tire Wear Patterns

To minimize wear and stress on the wheel bearings and tires, it is imperative that the tires are pointed in the right direction and at the proper angle relative to the road surface. This is called camber and castor by wheel alignment gurus and it is beyond the scope of this writers expertise to explain the complexities of these matters.

However, tire wear patterns will indicate certain alignment problems and suggests the repairs required to fix the misalignment. Catching tire wear early prevents blowouts. Keep a mechanical Tread Depth Gauge in your glovebox, and consider running a Tire Pressure Monitoring System (TPMS) to track heat and pressure changes that indicate dragging axles.

Cupping:Usually caused by an out-of-balance wheel, a bent rim, or worn shock absorbers.
One-Sided Wear:Typically points to an improper camber alignment.
Scrubbing or Feathering:Points to an improper castor angle or toe-in/toe-out misalignment.

DIY Suspension Upgrade Essentials

If you are tearing down your suspension to replace worn components, this is the time to upgrade from cheap factory parts to heavy-duty hardware that prevents future wear.

Heavy Duty Wet Bolt & Bronze Bushing Kits - Eliminates nylon bushing failures.
MORryde CRE3000 Suspension Equalizers - Adds up to 3 inches of suspension travel to absorb road shock.
RV Tire Pressure Monitoring Systems (TPMS) - Catch dragging brakes and tire issues before a blowout.

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When to Visit a Professional Alignment Shop

The average RV dealership or repair facility is not equipped to handle this type of repair and it is definitely not a do-it-at-home project. Only an alignment shop with the necessary equipment and trained personnel should be called upon to adjust the trailer wheel alignment. Most major cities will have at least one of these specialized shops. Check with your local dealers for a reference.