Showing my lack of mechanical knowledge here (all my experience is with motorcycles) ... I was trolling some other site and, regarding some Dodge or GM truck, a post mentioned a "semi-floating SFA 4X4". Wouldn't an SFA 4X4, especially one with locking hubs (say, my 2012 F-250) have to be full-floating by design? I can't picture a short drive axle that holds the wheel in place, yet can be disconnected to run in 4X2?

If I'm right, should I join that site just to ridicule the person that posted that ...ha ha...

 

Ford used full floating on both the front and rear.

Dodge and GM use semi in the front.

The difference is full floating the axle protrudes. More bearings then a semi too.

 

Technically, they are all full-floating. On the Dodge and Chevy, the axle stub rides in the splined hole, but the weight does not ride on that stub. It rides on the unit bearing, which bolts to the outer knuckle. Am I correct in my logic?

 

But only one bearing on a semi

 

Yes

Mildly on topic, by the logic put forth here is a corvette (C2-C4) rear end semi or full float?

 

A semi float axle carries weight on the axle shaft itself. (Stock) Ford 9" for example, or the 9.75 used in the late model F150's.

A full floater carries no weight on the axle shaft itself. The weight is supported by a hub and spindle, and the only thing the shaft does is turn the hub. D80, Ford/sterling 10.5, GM 14 bolt ( though there were a few oddball semifloats)

A front axle can't be a semifloat and still turn (well I guess it could but the wheel mounting surface would have to be part of the axleshaft itself, and I've never seen that). The older front axles still used a spindle and tapered roller bearings up front. Now they've found that unit bearings are easier and cheaper to slap in on the assembly line. But while the shaft may keep the bearings from coming apart on the Dodge and Chevy, it doesn't carry any weight on the shaft itself. Thus making it full float.

I'm going to guess the person that posted what you read meant that they did a SFA (solid front axle) conversion in place of an IFS setup, they just wanted to sound "cool". But wound up sounding dumb.