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Should I go 14 bolt?

Micah72

Micah72

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Kuna, Id
Starting to collect parts for a winter upgrade and trying to decide if I should go 14 bolt rear or not.
I have a '90 Jimmy with fairly stock 350, SM465, and a 12 bolt with Spartan and 3:73's now.
Driving with that spartan and a manual is starting to get old so will end up going selectable locker whether I keep the 12 bolt or go bigger.
14 sf and ff with 3:73 or 4:10's are pretty common around here and cheap.
I was thinking about finding a sf and using an H2 locker but not sure how reliable those are.
Would like to go as bolt in as possible and not worry about moving spring perches around.
This is more of a light trail use, overland build with 35's being my max tire size.

So, with all that, what are your thoughts?

Thanks
 
K85 Octane said:
agree
if you don't mind going to 8 lug, the answer is always yes
find a 14b out of a 3/4ton and you don't have to change anything except driveshaft u-joint and less likely, length.[/QUOTE

aaah, out of a 3/4 ton was some of the missing info I needed. There is a FF down the road out of a 3/4 ton camper special with 4:10's I was thinking about looking at.
Click to expand...
 
Measure yours real well, overall width, spring width. Take the tape measure with you
 
Yes x4 save yourself the headache and do it now before the build spirals into something more serious and you end up having a bad weak spot.
 
Not sure if you really need a 14-bolt but never a bad idea to go for it. Especially if you are planning on changing to a selectable locker anyway I would suggest putting the money towards a 14-bolt. While a 14SF is a nice upgrade from what you have if you go 14FF you shouldn't ever have to worry going to a bigger axle (unless you go monster truck style and need 2 1/2 tons or something).
 
I blew up 2 twelve bolts and a third was getting weak. So I went 14 bolt just so I didn't have to worry about it. 3/4 ton front got rid of my small bearing hub bearing as well (72 has a smaller outer hub bearing) I had been having issues with that too. Better brakes are also a plus. with 35s you are pushing the half tons either way if you are wheeling hard.
 
Odd man out here.

With 35s as the max tire size, you'll be plowing earth with the 14 bolt. Put a nice unit in the 12 bolt and keep going.

There's a lot of MAW with a 14 bolt. You've already committed to 35 and under which does not necessitate a rear plow of an axle.
 
I've always been an odd man out, 35" being my max size as well I'm with @obijuank5. The 14 is super heavy and scrub height will suffer with 35s. I've given this a lot of consideration with the purpose of my build. Keeping unsprung weight to a minimum for higher speed suspension, other than adding gussets and trusses where possible the 12 (I hope) should be fine with a Detroit locker and mosor's. Unless serious crawling I think the 14 is gonna eat up your power too. Imho.
 
SpeedlabDan said:
I've always been an odd man out, 35" being my max size as well I'm with @obijuank5. The 14 is super heavy and scrub height will suffer with 35s. I've given this a lot of consideration with the purpose of my build. Keeping unsprung weight to a minimum for higher speed suspension, other than adding gussets and trusses where possible the 12 (I hope) should be fine with a Detroit locker and mosor's. Unless serious crawling I think the 14 is gonna eat up your power too. Imho.
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Not to point at you directly but wanted to address the use of moser axles.




They are made of compressed farts and don't belong on the floor, let alone a truck.

This is coming from someone who drag raced for decades, so not just bagging on them
 
bent72 said:
Not to point at you directly but wanted to address the use of moser axles.




They are made of compressed farts and don't belong on the floor, let alone a truck.

This is coming from someone who drag raced for decades, so not just bagging on them
Click to expand...
well there's not much of an aftermarket for the 12bolt I'm guessing mostly bc everyone hates it lol. I'm working with what I have. It's not much weaker than a 9" Ford. Short of going 1ton, there's really no in between.
 
SpeedlabDan said:
well there's not much of an aftermarket for the 12bolt I'm guessing mostly bc everyone hates it lol. I'm working with what I have. It's not much weaker than a 9" Ford. Short of going 1ton, there's really no in between.
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12b seem to have a lot of pinion bearing failures, but honestly only once they are worn out anyway.
Mine got to 150k before it started going, and I figured it earned the right to give up.
The only in between on these axles is the 14 semi float.

They can be had in both 6 and 8 lug, the newer ones being disc brakes and of varying widths
 
bent72 said:
12b seem to have a lot of pinion bearing failures, but honestly only once they are worn out anyway.
Mine got to 150k before it started going, and I figured it earned the right to give up.
The only in between on these axles is the 14 semi float.

They can be had in both 6 and 8 lug, the newer ones being disc brakes and of varying widths
Click to expand...
But the sf is still rather large? You got me thinking I should send these moser axles back b4 I install and maybe go strange if they're available
 
Just based on what ive witnessed, Id never run a Moser. Strange did make full length truck axles at some point (probably still do). Ive run Strange for years with zero issues.

The SF is halfway between the case size of a 10b/12b and a full floater. Its not the rock catching truck anchor a FF is.

Having said that, a 14 shaved to a 13 bolt started getting pretty good at missing rocks.
 
I have
bent72 said:
Just based on what ive witnessed, Id never run a Moser. Strange did make full length truck axles at some point (probably still do). Ive run Strange for years with zero issues.

The SF is halfway between the case size of a 10b/12b and a full floater. Its not the rock catching truck anchor a FF is.

Having said that, a 14 shaved to a 13 bolt started getting pretty good at missing rocks.
Click to expand...
seen extensive shaving done to 14ffs where even the ring gear was turned.

A quick search turns up nothing for truck axles from strange but for now it's worth looking for.
 
Id give them a call. They like to know total axle shaft length, as that determines if it fits in the heat treat oven
 
6-lug 14-bolt Semi Floater from a GMT 400 , best of both worlds

Or go with the full Floater and shave it.


As some one who has broken multiple 12-bolts with 35" tires its not worth messing with.

IMG_1591.JPG
 
Last edited:
bent72 said:
12b seem to have a lot of pinion bearing failures, but honestly only once they are worn out anyway.
Mine got to 150k before it started going, and I figured it earned the right to give up.
The only in between on these axles is the 14 semi float.

They can be had in both 6 and 8 lug, the newer ones being disc brakes and of varying widths
Click to expand...
But the sf is still rather large?
yellowK20 said:
6-lug 14-bolt Semi Floater from a GMT 400 , best of both worlds

Or go with the full Floater and shave it.


As some one who has broken multiple 12-bolts with 35" tires its not worth messing with.
Click to expand...
gmt400? I'm starting to consider the sf14
 
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