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Last Call Guest on these Group Buy Deal Items from Baja Designs
9" vs D60, continued....
- Thread starter YotaAtieToo
- Start date
Tech Tim
Your AD Here....
What's the application?
Use?
Tire size?
HP?
Overall weight?
Hard to go wrong there.
2005 Jeep LJ custom chassis.
A 4 season Jeep capable of all but the buggiest trails , then drive to town for tacos and icecream.
40" max
na 6.0 LS sub 500 hp
4500-5k lbs.
14B would be more efficient on the hiway due to the higher pinion at 4 o'clock vs 5 o'clock. Not that fuel mileage matters.
YotaAtieToo
Thick skull
- Thread starter
- #874
Strange used to make a dropout for 12 bolt gears. Claimed it was 10% or so more efficient than a 9.
The pinion at the 3 o'clock position is the most efficient (low tooth drag) but also the weakest.
The pinion at the 6 o'clock position is the strongest but least efficient due to the friction of the teeth sliding.
12 minute mark or so.
YotaAtieToo
Thick skull
- Thread starter
- #877
Right, I just wondered if the power loss was enough to worry about.
Say a 105hp Toyota with a 14b or 9" vs a D70 or Toyota 9.5" (like 4 o clock)
If it's 10%, that a lot when you have 2 digit wheel hp
Say a 105hp Toyota with a 14b or 9" vs a D70 or Toyota 9.5" (like 4 o clock)
If it's 10%, that a lot when you have 2 digit wheel hp
triple_fcked
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Anecdotally, a 22re 4Runner I put a 9” rear housing into definitely lost some power on the butt dyno. Went from pulling a grade behind my shop in 4th to having to shift down to 3rd. I doubt it’s much to worry about unless you absolutely need all 90 squirrels as stated above
YotaAtieToo
Thick skull
- Thread starter
- #879
Now that you mention that, I can answer my own question. my buddy had a cookie cutter 1st gen 22re 4runner on 37s. Just like every other one except it had a 9" rear. I drove it once and was surprised how much power the stock rebuilt 22re had. Definitely not 10% loss.
Tech Tim
Your AD Here....
You're on the cusp.
A 9in would work great and if built right would live.
A 14 bolt would be a great solution, but a lot heavier.
The overall axle weight and rotating mass penalty of the 14 bolt would outweigh the small efficiency gain of the 14 bolt gear set.
RustyC is correct:
The pinion at the 3 o'clock position is the most efficient (low tooth drag) but also the weakest.
The pinion at the 6 o'clock position is the strongest but least efficient due to the friction of the teeth sliding.
But that is comparing two diffs of roughly the same size.
If you're talking two different sized diffs, you have to calculate the rotational mass and then consider the overall additional weight if there is a big jump. Let's say the 14B compared to a 9IN.
Back when I was running Wild West we did a bunch of TJ axle conversions for people. With similar Jeeps, tire sizes and gear ratios, the 9in-ers felt lighter and more nimble. The one-tons felt heavier and more planted. The TJs with the 9s could easily beat the TJs with tons in a side by side drag. The extra couple hundred pounds of weight made a big difference.
Those were for the bracket drag racers. iirc it was only 2-3% difference. Doesn't mean much to us as wheelers, but when you have really tight classes, that extra 3% could be the difference between 1st and 2nd place.
Right, I just wondered if the power loss was enough to worry about.
Say a 105hp Toyota with a 14b or 9" vs a D70 or Toyota 9.5" (like 4 o clock)
If it's 10%, that a lot when you have 2 digit wheel hp
No, the gear efficiency is not enough to notice in a big tire 4x4. As mentioned above, the increase in overall axle weight and rotational mass would be much more noticeable.
For example:
9in Air Locker = 28lbs (boxed weight)
14B Air Locker = 46lbs (boxed weight)
9in ring and pinion set weighs 20~ lbs.
14B R&P weighs about 25~ lbs
Now imagine spinning those weights. Which will be easier to spin?
Then add in that the 14 bolt ARB and R&P are both larger in diameter, so that weight is further from the axle centerline, taking even more power to spin.
Then add in the weight difference and yes, the rotational mass too. Again, heavier and bigger diameter.
The the overall weigh difference of the axles. Let's say the 14 bolt axles (F&R) are 200 lbs. heavier overall (probably low estimate). That's like carrying an extra person in your car.
YotaAtieToo
Thick skull
- Thread starter
- #881
That's why I mentioned 14b vs D70 and 9" vs toy 9.5" as close of apples to apples as I could think of.
Most people know how much going from toys/37s to 1tons and 40s slows it down, was just curious if the high offset had a big difference or not. Remembering my buddy's 9" rear 4runner makes me think it's not that much.
ScottRS
Not @Rockstomper today
I don't think the high offset makes that much efficiency difference in our world; back in the 90s and early 2000s the 9" vs d60 argument was pretty heated in the drag racing world. The argument generally was that the 60 mesh was enough more efficient to overcome the extra weight "penalty" in certain cars, if you had the appropriate traction and power available, where the 9" was stronger and lighter, at least when loaded the right direction.
I don't think anybody in the recreational crawler world is sufficiently gnats-ass precise to get to noticing the efficiency difference over the weight, and the minute we pay attention to it we start throwing in stuff like 40sp axleshafts, 14" rotors, 42" tires, and 1550 joints.
Where the high offset is concerning to me is when you run it wrong-way (ideally, backwards, because we're all running only drive side gear mesh going forward, right?); higher offset gains strength when loaded the right way, but trades it away in reverse, so backing up under high load gets riskier to the r&p. This would be a really interesting thing to explore with some variant of Bobby Long's (rip) back-when axle breaking machine, but I don't know how you'd really even accomplish that for apples to apples across multiple r&p sizes without it being eyewateringly expensive.
I don't think anybody in the recreational crawler world is sufficiently gnats-ass precise to get to noticing the efficiency difference over the weight, and the minute we pay attention to it we start throwing in stuff like 40sp axleshafts, 14" rotors, 42" tires, and 1550 joints.
Where the high offset is concerning to me is when you run it wrong-way (ideally, backwards, because we're all running only drive side gear mesh going forward, right?); higher offset gains strength when loaded the right way, but trades it away in reverse, so backing up under high load gets riskier to the r&p. This would be a really interesting thing to explore with some variant of Bobby Long's (rip) back-when axle breaking machine, but I don't know how you'd really even accomplish that for apples to apples across multiple r&p sizes without it being eyewateringly expensive.
350TacoZilla
Well-known member
Just me but if I was going to try and make a fuse like that I would just have a small stepdown in the shaft just behind the backing plate area. That way you reduce the risk of damage to the carrier/gears but also don't wad the shaft up in the spindle and bulge it out where you then can't get it apart.
Tech Tim
Your AD Here....
Typically the shaft will always fail at the smallest diameter.
Tech Tim
Your AD Here....
Excellent point.
ScottRS
Not @Rockstomper today
I have 37 spline inners and 35 spline outers on my jeep for this exact reason, but it's steer axles so what fails if something lets go at all, is off the shelf easy to change stub shafts. As rolled-spline production parts they're (maybe?) slightly stronger than cut-spline custom pieces of identical size, so 37sp being the next step up seemed like a good idea to leapfrog-over to.
I don't like the idea of making a custom part a fuse at all, but think if you're wanting to do what you're describing, the locking hub or drive flange is the place to do it (warn hub fuses, anyone?) on a non-steer axle. Problem still remains that some lockers puke their guts when you do that to them, so it's not a fix-all solution, just an option.
I secondarily don't like the idea of designing a fuse that pops in an inaccessible location (like in by the carrier) because it makes changing it more work than if it lets go somewhere that you can grab both broken parts.
350TacoZilla
Well-known member
Not to sound like too much of a cheap ass hurdur redneck commenter here but 14bolts are almost magical. Yes there are some reasons they are strong like the extra pinion support. But how the stock shafts and tubes hold up to what I've seen other dumb rednecks do is astounding. Spline count and shaft diameter don't seem to apply to them but they also aren't made from some mythical metal alloy either so how TF do they stay together?
arse_sidewards
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The only parts of a 14B with having are the ring, pinion and carrier. Everything else is some combination of over weight and under built. They’re better than the Dana stuff you could have found for the same price in 1999 and there’s basically no variation which is good for aftermarket but that’s about it.
'84 Bronco II
El Chingón
You do realize that while 14 bolt shafts are 30 spline they are not the same as Dana Spicer 30 spline shafts, right?
They are a larger pitch (coarser) than the Dana Spicer axle shafts, which are 24P (I believe) with a 30° pressure angle. The 30 spline 14 Bolt shafts are actually slightly bigger than the 35 spline Dana and Ford shafts.
94toytruck
Eastcoast crawler
Shafts and R&P are at least. Seen multiple bent tubes, spindles and broken centers in my friend group over the years. Great budget axle if you find the right version.
As stated the shafts are 30 but bigger than a 35s of standard variety.
FleshEater
Cheap Suzuki Guy
In a cralwer/buggy, this is a pretty important note, IMO. It’s pretty amazing how all that weight down low acts like a magnet to the Earth.
Pinion support, full float axles, and the axle tubes aren’t very long, so less deflection. I’m re-reading the Billavista bible right now, and he makes some excellent points on strength.
350TacoZilla
Well-known member
Yes, I just mean it like you see a ton of upgrades that people have to do to make a D60-70 survive in the same environment that a stock 14B seems to have no issue. You just go to the junkyard and select the 14b that fits your vehicle best width wise and you are set strength wise, obviously gearing\locker will still need done and maybe shave while there.You do realize that while 14 bolt shafts are 30 spline they are not the same as Dana Spicer 30 spline shafts, right?
They are a larger pitch (coarser) than the Dana Spicer axle shafts, which are 24P (I believe) with a 30° pressure angle. The 30 spline 14 Bolt shafts are actually slightly bigger than the 35 spline Dana and Ford shafts.
The spindles are only thing I have ever seen just straight out fail on them other than a shaft. I will say the thing about wadding a shaft in the spindle I have seen in person was a 14B, just seemed like bad luck as the shaft broke a few inches in at maybe 30 degree angle and bulged the spindle to the place where nuts had to be cut off. You couldn't tell what was going on with them in place but once the hub was removed it was obvious like a gun barrel bulge.
Good points.
arse_sidewards
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Available gear ratios and the available stock of "not 72+ wide" D60s and D70s back when such opinions were formed have a lot more to do with that than the ******s want to believe.
The year is 1999. Cleatus McSisterfuck swaps a 14B into his big block K5 on Humvee 37s keeping the 4.56 gears. Meanwhile Fanboy McWeeb over in desert ****holeville swaps a D60/D70 combo into whatever flavor of V6 at best Toyota he prefers and buys the stickiest 37s he can find. Both these people are every bit as ******ed as each other. But one of them is gonna put high 5s low 6 gears in and then go bind **** up and find the limit of the 32 spline at best shafts and gears and whatnot that the 1970s F250 he got his D70 from. And of course that LP front is ****ed no matter how you look at it.
Now 30yr later it's hard to argue a 2000s van D70 that comes 35spl from the factory isn't every bit as strong as a 90s 14B
'84 Bronco II
El Chingón
Well a 14 bolt is an all around bigger axle than a Dana 60, so what's your point? I think more or less the same thing can be said of Dana 70s and Sterling 10.25/10.5s. Sure there are people that break/upgrade them, but your average full body 1 ton swap rig is just fine with gears and locker with any of the 10"+ ring gear rear end options, the exception for the Dana 70s being Dodge's dumb 32 spline versions. The Dana 70 is the weakest of the options compared to the Sterling and 14 bolt, both shafts and gears, but it is the only option that goes lower than 5.38 gears.
The Ford Dana 70Us that came in the F250/350s are 35 spline
Tech Tim
Your AD Here....
The Ford Dana 70Us that came in the F250/350s are 35 spline
But stay away from the 70-2Us in the Dodge trucks and Ford van, they've got a weird pinion offset and you gotta do a bunch of grinding to get any standard Dana diffs to fit inside them. They're also only 32 spline.
