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What is the weight difference between a 12 bolt & a 14 bolt

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jonathanjay743

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I have seen all the guys with the 14FF upgrade. I have a 12 bolt rear & would rather lose some weight in my rig than gain it( I don't want my K5 to get a fat complex:D). Anyway just want to know what the weight difference is. My buddy parted out his Suburban that had a 14FF and said they are heavier than a tank. Anybody know what the difference is?
 
for the couple hundred pounds you'll gain by installing a 14b.......will more than work for you in strength.


Wait'll you think about a D60 for the front then, you''l bust an o-ring when you try to move the 500 lb pig. by yourself.
 
strength over weight :) you pretty much cant break it

disks will save you ~50lbs over 13" drums...
 
Its a trade off sometimes , a well prepared 1/2 ton axle , experienced driver , and not too heavy a rig can go a long ways .

Of course the 14bff can go along ways from the get go , after you back up so the diff clears that rock :wink1:
 
you cant compare a 14FF to a 12 bolt. the advantages FFAARR out weigh the disadvantages of weight. if your ONLY doing light trail blazen then yea, dont bother to do a 14FF swap. but if you plan on some even decent wheelin and you have a decent size tire then a swap IMHO is warented. sure you could make a 12 bolt better, but why when 14FF ars so cheap to build.

for what you would put into a 12 bolt, do the same with a 14ff and you've got a WWAAYY better axle period. if you want to save some weight take you hard top off and run a soft top. you will be less top heavy, especially having the "extra weight" of a 14FF down low, Kinda like a boat ancor :D.
 
So does anyone have an actual number to answer the original question?
 
I have herd a complete 14FF is in the range of about 550?? around there. a 12 bolt has to be 250, maybe 350 at most I would think. its been a LONG, LONG time since I played with any axle as small as a 12 bolt. I only play with the 1 ton stuff.
 
Just a little out of the box, if you don't mind a little fab work, consider a Ford 9". Light (240 lbs) strong and a good amount of clearance. 31 spline semi floater, 9 inch ring gear and cheap to build. I put a Ford 9 in my K5 to get rid of the 10 bolt. Didn't want the weight of the 14 but something stronger than a 10 bolt.

Sent the shafts off to Moser and had them fill and redrill for 6 on 5.5 and then I redrilled the drums. Depending on the amount of lift you have you may have to get the rear drive shaft lenghtened and a conversion u-joint put on the axle end. Plus both axle shafts are the same length depending on the donor vehicle (pickup and broncos) so you only need one spare.

PaulC
 
Another option is a Dana 60 rear axle in the full-floating variety. Clearance isn't much different than a 12blt and it's a full-floating axle. Weight would be between a 14bFF and 12blt.

I see a lot of them for sale on local boards and on Pirate 4x4. Not as common and cheap as a 14b, but not a bad alternative.
 
mrk5 said:
Another option is a Dana 60 rear axle in the full-floating variety. Clearance isn't much different than a 12blt and it's a full-floating axle. Weight would be between a 14bFF and 12blt.

I see a lot of them for sale on local boards and on Pirate 4x4. Not as common and cheap as a 14b, but not a bad alternative.
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ahh yes, a good alternative. I like the D60 over a 9 incher, heavier duty and full floating. I have one in my 70' chevy with 4.56 gears and a disc swap I made myself. just need a air locker for it.
 
Just a little out of the box, if you don't mind a little fab work, consider a Ford 9". Light (240 lbs) strong and a good amount of clearance.
Click to expand...

i was going to do a mini-hijack and ask about this. thanks.
 
The D60 is stronger than a Ford 9" ? That isn't right is it?

Is the 9" not available as a full floater?
 
I would say so, especially a D60FF just because of the FF if for no other reason. That's not to say a 9" can't be made to be stronger, we're talking factory trim here. Something available out of the JY.

Doesn't 9" refer to ring gear diameter. The D60 ring gear is 9.75"D. Ford 9" was available with 28 or 31 splines, D60 30 or 35 splines.

It wouldn't surprise me if there's a FF kit for the 9", but I don't believe they came that way from the factory.

I admit I don't a lot about D60 rear axles. I'm a Mopar muscle car guy and I know that was the axle used in the Hemi Cudas. :dunno:
 
Yes a 60 is stronger than a Ford 9. But it all depends on what jonathanjay743 is trying to do. If he is trying to get a stronger but light weight rear axle and without swaping out wheels from a 6 lug to a 8 lug then I would go with a junk yard Ford 9.

Compare a Chevy 12 bolt to a Ford 9. Chevy 12 bolt has a 8 7/8" RG while the Ford 9 has a 9" RG. The Chevy 12 is a 30 spline C-Clip while the Ford 9 has a 31 spline semi float. Chevy 12 has 2 pinion bearings while the Ford 9 has 3 pinion bearings. Chevy 12 and Ford 9 have about the same ground clearance and have the same weight. Chevy 12 doesn't have near the same selection of aftermarket support as the Ford 9. The biggest spline axle you can get for a Chevy 12 is 33 that takes welding new housing ends on the housing. Ford 9 can take up to 35 without modification to a big bearing housing. Chevy 12 bolt has larger carrier bearings and a Ford 9.
 
When you break the 12 swap in the 14. I beat on 12 bolts with 35" tires for a long time before I decided to swap. The pinion bearings let go on mine so it was time to retire the old girl... had I broken an axle shaft I would have slapped a new shaft in and kept going. ;)

EDIT: now that I'm 60/14 I break way more axle shafts and driveshafts because my foot got heavier when I upgraded. (tire size also went 40+)
 
My 12 bolt may be big enough. I am currently running 33" tires & don't think I will go over 35" tires. I use this as a work truck too & I rock crawl with it when I can. I'll probably eventually put a locker in it. I've been wheeling an FJ40 with a Detroit & never needed larger axles with it than the stock setup. With the weight thing, I want the best possible gas mileage (Im dang frugal :wink1:)& clearance (for my size tires). From what I gather anything over a 35" requires the 14FF.
 
jonathanjay743 said:
My 12 bolt may be big enough. I am currently running 33" tires & don't think I will go over 35" tires. I use this as a work truck too & I rock crawl with it when I can. I'll probably eventually put a locker in it. I've been wheeling an FJ40 with a Detroit & never needed larger axles with it than the stock setup. With the weight thing, I want the best possible gas mileage (Im dang frugal :wink1:)& clearance (for my size tires). From what I gather anything over a 35" requires the 14FF.
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You can do up to a 38" tire (I have anyways) and keep the 12 alive.

I say 37+ is time for a 14 anything less just requires that you drive with some reserve on the throttle input.
 
The weight difference can't be that great between a 12 bolt and 14 bolt...

I would only bet a few onces. I could even go weigh 2 bolts in my garage and tell you the exact amount if you need it.

















































Welcome to my Friday.....:haha:
 
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