A A M M E E R R I I C C A A N N A A LC, GS, and LTModel Fifthwheels Alko Axles Smooth Ride If you were going to set out to build the best trailer suspension system in the world, what criteria would you have to meet? Well, ofcourse you would have to come up with a system that would isolate and dampen the effects of road bumps and chuck holes, giving you that smooth ride you have always dreamed of. But if you could 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 indus- tries 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 swing- ing 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 impact- ed 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 momen- tum 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 vehi- cles 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 with the hydraulic (liquid) or air filled shock absorber, usually referred to A sunny December morning at the Alko Axle factory in Indiana where axles are made for the Americana model fifthwheels. The very clean interior of the AL-KO factory.
Transcript
AAMMEERRIICCAANNAALC, GS, and LT Model Fifthwheels
Alko Axles
Smooth Ride
If you were going to set out tobuild the best trailer suspensionsystem in the world, what criteriawould you have to meet? Well,ofcourse you would have to comeup with a system that would isolateand dampen the effects of roadbumps and chuck holes, giving youthat smooth ride you have alwaysdreamed of. But if you could addoverall stability to the coach as well- genius. Sounds simple, but asmooth ride hasn't always been inthe cards for travelers.
For several hundreds of years thehorse drawn wagon, horse carriage,train, truck, and automotive indus-tries have relied on the same, andobviously very old technology -
bowed leaf metal springs. Theseleaf springs are traditionallyattached to the two sides of a singleaxle and then by means of a swing-ing bracket areattached to thataxle. The idea isto take the jarringout of thoseaforementionedbumps and chuckholes, which thissystem does, butnot without a fewproblems alongthe way.
In application,when one side ofthe axle is impact-
ed by a bump or hole in the road,the effect is to flex the spring eitherup or down, and that flex is"telegraphed" to both sides of theaxle. An unfortunate side effect ofleaf spring flexing is that after it hasbeen flexed it will not just return toits original position. The momen-tum of the flex of the spring propelsthe axle, along with the weight ofits attached tires and wheels, in theopposite direction of its originalflex and beyond the original "0"point, thus creating the infamousbounce.
This bounce in today's road vehi-cles is magnified by the additionalspring effect of compressible airinside a rubber tire. In order toattempt to counteract this bounce,suspensioneers have come up withthe hydraulic (liquid) or air filledshock absorber, usually referred to
A sunny December morning at the Alko Axle factory in Indiana where axles are madefor the Americana model fifthwheels.
The very clean interior of the AL-KO factory.
as simply "shocks". While theshocks do diminish the bounce,they don't get rid of it, but they doadd another expensive limited lifereplacement part to an alreadyimperfect system.
A more ideal suspension systemwould do several things. First, itwould isolate the movement of atire or wheel to it's particular spin-dle and not let its movement affectany other wheel or tire. Second, itwould allow the wheel and tire tocompress or extend as it handles the
bumps and holes in the road with-out recoiling beyond the "0" point.In other words, it would keep thebounce at bay.
Fortunately for us, but perhapsunfortunately for you if you werethinking about all those royaltiesyou were going to collect from theperfect suspension system you weregoing to invent, there is a moderntechnology system that does justthat. It was first developed inGermany and later applied to trail-ers in the USA. For decades thedesign helped Airstream traveltrailers earn the reputation of beingthe best towing trailer built in theUS.
The system uses two simple prin-ciples. An independent, trailingarm suspension in which only thearm that is attached to a particulartire moves when that tire hits abump, and a compressed rubbersuspension system within the axleitself that isolates and dampensbumps in the road without relying
on springy springsthat have a lot ofzing to theirspring and keepwanting to spring.
How does thiswork? Well rub-b e r , w h e nsqueezed, onlywants to return toit's original shapeand does not wantto reboundbeyond its origi-nal shape. Forexample if you squeeze a rubberball and let go it will just becomeround again; it won't reflex beyondthat shape.
Therefore, by using "rubber incompression" as the key to a trail-ing arm independent suspension, abounce free suspension system canbe created, meaning the tire andwheel do not want to reboundbeyond the "0" point. This, com-bined with independent tire andwheel action that is not transmitted
to the opposite side of a vehicle,effectively makes a vehicle withthis type of suspension ride "twiceas well" as a unit suspended by theold fashion spring and shock sys-tem.
Not only does this type of sus-pension give us a better ride, thereis an added benefit as well.Because the tube axle that joins thewheel and spindle assembly fromone side of the Americana model tothe other does not have to bounce
Lowering the axle before inserting the compressible rubber.
As the axleoperates, thetrailing armswings up anddown, com-pressing therubber.
The Oscillation diagram above shows thedifference in performance between the Al-KO Rubber Suspension Axle and a con-ventional leaf spring axle.
3 rubber dampening elements
Independent rubber tube
Hollow space forindependent action
Top mount or sidemount brackets
Automotivealignmenttechnology
2
up and down with the tires andeverything as a leaf spring type ofaxle would (remember, the armwith the wheel attached moves, butthe axle itself does not, see theillustration to help visualize this),we do not have to leave a big emptyspace between the chassis and theaxle to accommodate this. With astandard leaf spring suspension,you would have to have six inchesclearance above the axle. Since wedon't have to do this, we can lowerour center chassis carry throughsection right down to the axle. Thisgives us the ability to have an 18"web section in the axle carrythrough section of the chassisframe. This addedstrength, along withour GS specificationfor a 2" x 2" lowerchassis torsion (twist)prevention crossmember, gives us asuperior chassis forproper support ofslide-out roomdesigns (see the onesheet "Why Don't WeEver Learn" to learn
more about slideout fit). All thisadded strength means less flex,which means the chances for us tohave problems with slide-out fitand leaks are much less than if wehad a traditional leaf spring suspen-sion. The GS specification forchassis design, which includes thecombination of a deep center websection in the axle attached area ofthe chassis, and a heat treated 10"junior "I" beam front to back, is notonly the strongest design to preventchassis over flex, but combinedwith 16" wheels gives us the bestground clearance in the industry.
Because the suspension is movedoutboard, toward the outside of the
trailer, with the pivot points locatedout with the wheels, this suspensiongives us added stability. The effectis similar to spreading your feet inorder to have a stronger stance.You’re much less likely to fall overwhen pushed if you have your feetspread apart than if your feet weretogether. This added stabilityallows us the luxury of raising ourcenter of gravity in order to achievea higher chassis frame with addedground clearance, as well as addedclearance below the fifthwheel bed-room for 4 X 4 trucks withoutincurring any kind of pendulumeffect (swaying from side to side)while traveling down the road.
In fact, because of this superiorsuspension system that just doesn'tseem to want to rock or move whileparked, many of our customers findthat it is unnecessary to lower therear stabilizing jacks on theAmericana model when they dopark.
But the primary benefit to thissuspension system is the ride. Mostof our customers don't actually ridein their fifthwheel (even though it islegal to do so in many states), buttheir dishes do. A smooth ridekeeps "things" in their cabinets,which is where you want to findthem when you get somewhere, notall over the floor. I can't think of
one person who thinksits fun to open the doorto their fifthwheel andfind the T.V. on the floor,chairs strewn around,and dishes everywherebut where they are sup-posed to be. A smoothlytowing unit is as much apleasure as a poorly tow-ing one is an annoyance.
Looking up at the 18 inch vertical web section. Note the 16 inch wheel and the 12 inchoversize brake drum, the same size used on the seven thousand pound axle, giving usbetter cooling for those long mountain downhill runs.
Careful attention to detail means sound and safe brake assemblies
