Newbie question- difference between 14ff &sf

[odoa3]

I take it a 14ff stands for full float and the sf stands for semi float? What is the difference between the two? Which one is stronger? How do you tell the difference between the two? My father has a 14 bolt out of a 3/4 ton, early 80's Suburban he will be shipping over to me. Any guess which one it may be? Thanks for the education.

 

[Z3PR]

[ QUOTE ]
I take it a 14ff stands for full float and the sf stands for semi float? What is the difference between the two? Which one is stronger? How do you tell the difference between the two? My father has a 14 bolt out of a 3/4 ton, early 80's Suburban he will be shipping over to me. Any guess which one it may be? Thanks for the education.

[/ QUOTE ] The FF is stronger. The FF has the bolts in the center of the hub. It has 8 lugs.

 

[BranndonC]

14FF is stronger and is 8 lug, 14SF is weaker and is 6 lug usually, thats all i know. Sorry /forums/images/graemlins/peace.gif

 

[84_Chevy_K10]

The difference is in the entire design.

A semi floating axle uses the axleshafts to both drive the vehicle and support the weight. If the axle shaft breaks, the tire will exit the vehicle.

A full floating axle uses the axleshaft to drive the vehicle and the housing itself to support the weight. So, if the axle shaft fails, the weight of the vehicle is still supported by the axle housing.

While the comments about the FF being stronger is true, it is the nature of the design that make this a reality.

Even though the Dana 60 rear comes in both semi and full floating designs for a rear axle, the full floater is going to be significantly stronger despite using the same carrier and ring and pinion set.

The 14 bolt full floater is stronger because of its full floating design and the fact that it also has a bigger center section and larger ring and pinion, as well as a better pinion support design.

The 14 bolt full floater cannot really be compared to a semi floating axle in terms of strength. A 14 bolt SF is much like a "12 bolt on steroids" but a 14 bolt full floater is up there in strength with Dana 70, stronger than a Dana 60 FF and similar to Ford's full floaters in size/strength as well.

Crazily enough the 14 bolt SF uses 33 spline axles and the 14 bolt full floater is 30 spline. /forums/images/graemlins/thinking.gif /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/dunno.gif

 

[odoa3]

Well, from you guys have told me- my 14 bolt is a ff. Excellent! Thanks for the explanation. /forums/images/graemlins/thumb.gif

 

[84_Chevy_K10]

In this case a picture would be worth a thousand words, but when you go to take it apart, you'll understand more about the design. /forums/images/graemlins/thumb.gif

 

[DwarF]

Hrm, I looked at the torque ratings, and the sf is almost as strong as the ff for torque (95%), so I don't think it's quite fair to call it a 12 bolt on steroids. If you aren't putting that much muscle to it, then the SF isn't a bad axle. In fact, it has more clearance than the FF, and is almost as stong. However... if you don't run c-clip eliminators, then you will have to pull you whole diff apart if you break an axle, and the wheel "could" exit the vehicle if the axle breaks and you keep driving. You can get them in 8 lug as easily as you can 6 nowadays. I have broken axles on the trail before (not my 14 SF) and you will have to fix it there. You can drive it out, but you will have to rig something that belts around the outside of your wheel to hold it in. If the axle is broken, you probably shouldn't be trying to drive it out, regardless of if it is a ff or sf.

 

[84_Chevy_K10]

C clip eliminators are not made or designed for road use and all of them leak.

Torque input rating is not what you're concerned with for an off road pounding.

I had a 14 bolt SF in the rear of my rig for nearly 3 years and have a FF now, but an SF does not compare to a FF in strength. Not even close.