pontoon trailers - Axles Bearings and Hibs
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Pontoon Trailer: Axles, Hubs & Bearings

The axle itself is nothing but a piece of steel with a spindle and mounting plate welded to each end. Some trailer manufacturers make their own axles while others find it simpler to purchase them. Axle manufacturers have worked to build brand name recognition: Al-Co, Dexter, Reliable etc. There may be some slight benefit of one brand over another. The quality story, if there is one, lies in the bearings and the hubs. Hubs are rated by their carrying capacity and have to meet certain Department of Transportation requirements for the rating. Thus an axle with “cheap” imported hubs and bearings (and most of them used today are imported) will do what it’s supposed to do. You’ll seldom hear a pontoon trailer manufacturer touting the quality of their axles. There really just isn’t much to claim, except the carrying capacity.
pontoon trailer axle
pontoon trailer axle hub
Axles are vendor items for most trailer manufactures. Axle builders usually just spray paint the axles. They get scratched in transit and assembly. They seldom get touched up. Some companies claim they’re beneath the trailer, no one will notice. But many boats are off the trailer, often six months a year, when the axles rust, you will notice. Custom builders and higher quality companies use Aluminized axles. An aluminized coating helps prevent corrosion. It’s just cosmetic and isn’t much more expensive, but it’s a clue to the quality of the trailer your buying.
pontoon boat axle
Aluminized Axles Rusty painted axles
pontoon trailer axle types
pontoon trailer spring axle attachmentspring axle attach on pontoon trailer
Spring axles are mounted with U bolt, these are called hanger brackets. There is no wrong or right way to mount them. I prefer when the bracket and nuts are on top. Many trailers are assembled on site, at a dealer or distributor, rather than at the manufacturer. It’s an extra safety precaution to be able to see that the nuts are on tight. The image to the left is Aluminized, nuts on top. The image to the right is painted with nuts on the bottom.
Adjustable Axles
Some large national trailer manufacturers use adjustable axles. It’s a feature that is usually not advertised because adjustable axles have gotten some bad publicity. The benefit is to the manufacturer. They can stack more trailers for shipping if the distributor or dealer puts the axles on.

Bolting the axle is not generally a cost savings to the manufacturer. But it is a labor saving benefit in the manufacturing process. Attaching the axle to the frame is done by the distributor or dealer. This has given bolt on axles a bad reputation.
bolt on axles mounted crooked

People assembling trailers in distributors or dealerships are generally not master mechanics, more often they are low paid “yard boys”. The chances of getting an axle on crooked or misaligned can be great. Even just off an inch will make the trailer “dog track” and wear the tires. Another problem is if the bolts aren’t on absolutely tight, a extreme shock (such as a pot hole) can loosen the bolts.
Spring Axle Assemblies
The majority of pontoon trailer manufacturers use spring axle assemblies.
Pontoon Trailer Spring Assemblies
Springs, like axles, are almost generic. When properly matched they carry your pontoon smoothly on good roads and help take the bounce out of rough ones. The axle assembly derives it’s capacity from the rating of the hub and the number of leaf springs. Fishing boat trailers may have only two springs. Most pontoon trailers will have four and heavy duty trailers may have five springs. Most trailer manufacturers simply state that the axle has a capacity of 2000, 2700, or 3500 lb. It’s usually stamped somewhere on the axle. The trailer owner should be aware of the carrying capacity. A axle with a 2700 lb. carrying capacity matched with a trailer that weighs about 600 lb. means the pontoon trailer can carry about 2100 lb. Most modern pontoon boats are over 2000 lbs.
The Weight Equalizer
spring equalizerI generally prefer spring axles to torsion axles. Especially for larger heavier pontoons for one simple feature. Spring axles tied together in a tandem axle system have the weight of the load (boat) equalized by a “rocker” in the middle. It helps distribute the weight of the boat between the front and back axles, equalizing the load. It is a big benefit on bad roads. If the front wheel goes down in a pot hole, the equalizer raises the back wheel so as to prevent it from falling quite as deep in the hole. Helping it to “walk” over the hole. You’ll feel the jarring effect of the front wheel but the back wheel won’t hit quite as hard.
Torsion Axles
torsion axles
An alternative to spring axles is the sealed rubber torsion axle system. Springs are replaced by rubber cords inside the axle. The rubber cords are compressed by the “torsion” or twisting of the axle inside. One of the advantages of the torsion axle system is that it is very simple to mount. It’s a benefit to the trailer manufacturer and distributor/dealer. They can ship more trailers on a stack. The distributor/dealer can more easily mount a torsion axle than a spring axle. Usually just four bolts. Generally speaking torsion axles are slightly more expensive, but if you are shipping trailers cross country, there is freight savings with the more trailers you can stack.

I sold a line of trailers that used torsion axles for years. The claimed benefit was that they offered a smoother ride. When I was approached by another manufacturer I told them of my preference for torsion axles. Through actual towing demonstrations I was shocked to realize that I could not feel any difference. In fact, the spring axle handled a rough road better than the torsion axle. You can search the internet for the pros and cons and there may be some benefit towing with a smaller tow vehicle, but for modern pontoon boats I recommend and prefer the spring axle.
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