Quote:
Originally Posted by ABOBB
A true full floating axle can FLOAT!!!
That means that it can move (with restrictions) completely independently of the differential and the hub. There are trucks out there with full floating Dana 80's and even some Sterlings...but they have aftermarket axles in them.
When making stronger axles for pulling or other competion, the axle has no flange on the hub end. It is splined on that end, the same as the differential end, and those splines mate with a splined drive plate that bolts to the hub in place of the flange. The axle is then capable of floating from side to side (at least withing the restrictions of the splines) without the differential or the hub ever moving laterally. That is a FULL floating axle. An axle who's lateral motion is restricted in any other way is not FULL floating, but semi floating.
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Sorry but you're wrong.
Here's a good write-up that explains it: There are several basic rear axle types used in 4x4s, and each have specific design pros and cons. Axle designs can vary in load handling, bearing and flange type, and gearset configuration. In this article we'll take a look at rear axles and discuss the benefits of various designs.
SEMI-FLOATER vs. FULL-FLOATER There are two types of rear axles found on light-duty 4x4s: semi-floating and full-floating. Each has its advantages and disadvantages.
A semi-floating axle is very common on the rear of most 4x4s. It consists of an axleshaft on each side that is splined on the inner end where it mates to the differential and has a wheel flange where the wheel studs mount at the other end. This assembly typically mates to the end of the axlehousing using some type of flange arrangement. The axleshaft also rides on a large roller or ball bearing out at the end of the axlehousing.
The axleshaft in a semi-floating assembly serves two purposes. First, it attaches to the wheel and is used to support the weight of the vehicle and its cargo. Second, the axleshaft must transmit the rotational torque from the differential out to the wheel.
A full-floating axle can be found on the rear of some 4x4s, but it is generally reserved for vehicles that are designed for severe duty, or are intended to carry heavy loads. This type of axle uses an axleshaft on each side that is simply splined at both ends or splined on the inner end and has a drive flange on the outer end. The shaft mates to the differential in the same way as a semi-floater. However, the outer end of the shaft differs. Here, the splined end of the shaft slides into a locking hub or an internal splined steel drive plate that bolts to a hub cap, similar to what is found on a front axle. In some cases, the drive flange may be part of the shaft itself. In either case, the axleshaft is allowed to float in the system.
For a full-floater system, the axleshaft only serves to transmit the rotational torque from the differential out to the wheel. It does not carry the weight of the vehicle like a semi-floater does. On a full floater, a spindle is attached to the outer end of the axlehousing. The hub's cap is attached to this spindle and rides on tapered roller bearings. It is this assembly that carries the vehicle weight. As such, a full-floating axle system is considerably stronger than an equivalently sized semi-floating system.
For those of you who carry heavy loads, this means your axle load capacity is greatly increased with a full-floater. Load ratings for similar vehicles with the two different axles are usually significantly different. If you do hard-core 'wheeling on big tires, a full-floater means that your axleshafts can also handle much more loading than a similar semi-floater could because it now must only handle torque loading.
Further advantages of a full-floater include being able to remove a broken axleshaft, yet still have the ability to keep a functional rolling tire on that corner of the vehicle. This can be done since the wheel actually bolts to the hub that rides on the spindle attached to the axlehousing. If the axle has manual locking hubs, it may be possible to unlock the rear hubs for towing a disabled vehicle on the trail or for flat towing over the road.
It is now possible to convert some semi-floater rear axles to full-floaters using aftermarket kits. These kits allow an owner to easily upgrade the axleshaft strength of his axle. However, such a kit does not upgrade the differential assembly, so axles with this portion as a weak link would not benefit much from such a conversion.
11-03-2009, 03:34 PM
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