add overall stability to the coach as well - genius. Sounds simple, but a smooth ride hasn't always been in the cards for travelers.
For several hundreds of years the horse drawn wagon, horse carriage, train, truck, and automotive industries have relied on the same, and obviously very old technology - bowed leaf metal springs. These leaf springs are traditionally attached to the two sides of a single axle and then by means of a swinging bracket are attached to that axle. The idea is to take the jarring out of those aforementioned bumps and chuck holes, which this system does, but not without a few problems along the way.
In application, when one side of the axle is impacted by a bump or hole in the road, the effect is to flex the spring either up or down, and that flex is "telegraphed"" to both sides of the axle. An unfortunate side effect of leaf spring flexing is that after it has been flexed it will not just return to its original position. The momentum of the flex of the spring propels the axle, along with the weight of its attached tires and wheels, in the opposite direction of its original flex and beyond the original "0" point, thus creating the infamous bounce.
This bounce in today's road vehicles is magnified by the additional spring effect of compressible air inside a rubber tire. In order to attempt to counteract this bounce, suspensioneers have come up
 The very clean interior of the AL-KO factory. |
A more ideal suspension system would do several things. First, it would isolate the movement of a tire or wheel to it's particular spindle and not let its movement affect any other wheel or tire. Second, it would allow the wheel and tire to compress or extend as it handles the bumps and holes in the road without recoiling beyond the "0" point. In other words, it would keep the bounce at bay.
Fortunately for us, but perhaps unfortunately for you if you were thinking about all those royalties you were going to collect from the perfect suspension system you were going to invent, there is a modern technology system that does just that. It was first developed in Germany and later applied to trailers in the USA. For decades the design helped Airstream travel trailers earn the reputation of being the best towing trailer built in the US.
The system uses two simple principles. An independent, trailing arm suspension in which only the arm that is attached to a particular tire moves when that tire hits a bump, and a compressed rubber suspension system within the axle itself that isolates and dampens bumps in the road without relying on springy springs that have a lot of zing to their spring and keep wanting to spring.
How does this work? Well rubber,when squeezed, only wants to return to it's original shape and does not want to rebound
 Moving the axels from the rubber insertion station to the brake station. |
Therefore, by using "rubber in compression" as the key to a trailing arm independent suspension, a bounce free suspension system can be created, meaning the tire and wheel do not want to rebound beyond the "0" point. This, combined with independent tire and wheel action that is not transmitted to the opposite side of a vehicle, effectively makes a vehicle with this type of suspension ride "twice as well" as a unit suspended by the old fashion spring and shock system.
Not only does this type of suspension give us a better ride, there is an added benefit as well. Because the tube axle that joins the wheel and spindle assembly from one side of the Americana model to the other does not have to bounce up and down with the tires and everything as a leaf spring type of axle would (remember, the arm with the wheel attached moves, but the axle itself does not, see the illustration to help visualize this), we do not have to leave a big empty space between the chassis and the axle to accommodate this. With a standard leaf spring suspension, you would have to have six inches clearance above the axle. Since we don't have to do this, we can lower our center chassis carry through section right down to the axle. This gives us the ability to have an 18" web section in the axle carry through section of the chassis frame. This added strength, along with our GS specification for a 2" x 2" lower chassis torsion (twist) prevention cross member, gives us a superior chassis for proper support of slide-out room designs (see the one sheet "Why Don't We Ever Learn" to learn more about slideout fit). All this added strength means less flex, which means the chances for us to have problems with slide-out fit
 The brakes being put together in the ALKO factory. |
Because the suspension is moved outboard, toward the outside of the trailer, with the pivot points located out with the wheels, this suspension gives us added stability. The effect is similar to spreading your feet in order to have a stronger stance. You're much less likely to fall over when pushed if you have your feet spread apart than if your feet were together. This added stability allows us the luxury of raising our center of gravity in order to achieve a higher chassis frame with added ground clearance, as well as added clearance below the fifthwheel bedroom for 4 X 4 trucks without incurring any kind of pendulum effect (swaying from side to side) while traveling down the road.
In fact, because of this superior suspension system that just doesn't seem to want to rock or move while parked, many of our customers find that it is unnecessary to lower the rear stabilizing jacks on the Americana model when they do park.
But the primary benefit to this suspension system is the ride. Most of our customers don't actually ride in their fifthwheel (even though it is legal to do so in many states), but their dishes do. A smooth ride keeps "things" in their cabinets, which is where you want to find them when you get somewhere, not all over the floor. I can't think of one person who thinks its fun to open the door to their fifthwheel and find the T.V. on the floor, chairs strewn around, and dishes everywhere but where they are supposed to be. A smoothly towing unit is as much a pleasure as a poorly towing one is an annoyance.
 The components that make up the AL-KO axle. |
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