Axle shaft strength?

[Halfbox P]

First thanks for the info so far. You guys have been a wealth of information for my build.
OK I know that a 35 spline axle is stronger than a 30 and that alloy axles are stronger than stock. Does anyone have specific strength numbers? Will an alloy 30 spline be stronger or weaker than a stock 35 spline?
I want to worry less about breaking rear axle shafts and build a full float rear with lockouts for my trail Scout. The 30 spline 44 I have been running has a Detroit and I can get the parts for the full float fairly cheap at Pull & Save the custom alloy shafts from Dutchman's are about $470.
To build a 35 spline 60 to the same specifications I'd be looking at about $1500 by the time I got the locker, gears, axles, and lockouts.
My third option would be to build the 44 now and upgrade to a 30 spline 60 later (if that is an upgrade) using the 30 spline alloy axles from the 44.
I know the 60 or a Corp 14 would be stronger but if I can run the 44 I won't loose ground clearance.

Truck specs 72 Scout II, SOA on stock springs with add a leaves, 3.73 gears Chevy front 44 narrowed for Wagoneer axles, Detroit electrac, flat tops, hi steer with cross over steering, Ford outers. Scout 44 rear Detroit Soft Locker and disk brakes. Dodge 360, 727, Twin Stick Terra Low Dana 20, and 35's.
http://www.justih.org/photopost/data/567/Naches_Run_38.jpg

[Old Scout]

JP magazine did an axle test in their November issue and heres what they said.....
1: A stock D44 axle broke at 35* of twist and 3500 ft.lb
2: A 4340 chromoly hardened shaft broke @ 35* of twist and 4500 ft.lb
3: A 35 spline D60 shaft broke @ 30* twist and 8100 ft.lb
4: A 4340 chromoly D60 shaft broke @ 130* twist and 10,500 ft. lbs
http://www.pirate4x4.com/forum/showpost.php?p=6204743&postcount=3

[binderbound]

Enlighten us to your cheap FF 44? Did it to mine and was in it $1300 counting gears, Detroit, all new brakes, bearings, flanges, and shafts. I did all the work with help from friends. So that is just a parts costs.

Or are you just gonna copy my build since you have the gears and locker already?

*edit* that list from OS doesn't show a 30 spline 60 but you can figure the shaft strength is roughly the same between the 44 and 60. So cromo 30 spline 44 shafts would be stronger than a stock 30 spline 60. But you wash that out in ring gear strength.

[Halfbox P]

Thanks for the info OS.
Binderbound, I don't think I've seen your ff but I was looking at using small bearing front spindles, brackets and calipers off of a Chevy or Jeep and Ford Rotors the same as I'm running on the front. I can get the used parts for around $60 at the local P & S. Then I would need to get the axle shafts ($470) install inner seals and build flanges to bolt the caliper brackets to. The advantages for me would be only needing to carry one set of spare parts for both ends and retaining good ground clearance.
With the info OS posted only gaining 1000 lbs torque with the 30 spline chromoly's I don't know if it will be worth the build. I've snapped stock 30 splines at less than 2 MPH with no wheel spin.

[binderbound]

It takes a fair amount of machine work to make the fronts go on the rear. The ID of that spindle is only about 1.28 +/-. So you need to bore the spindle to atleast 1.32 but 1.34-.35 is better. How much wall thickness do you have now? The next problem is the flange. The spindle has that fat lip that goes in the knuckle. It won't fit in the rear end bearing space so it needs to be turned down. Now you fit it up and no bolt holes match anywhere. You have to re-drill the axle flange to match your spindle pattern.

Search my build 'TracTracTor Offroad project 2' I think I named it. Its been a while.

At the end I think I have a pic of my dutchman shaft next to an IH 60 shaft. Even though they both are 1.31 at the splines, the dutchman goes up to almost 1.33 in the middle, where as the 60 necks down to 1.28 in the middle.

Its a shit ton of work for not much gain but I did it for the bling factor. Not to mention the clearance and lighter weight too.

[Halfbox P]

I was just reading over your thread, good info.

[472Scout]

Seeing that you're running 35's I doubt you'll save money in the long run by sticking with the D44. Build a 60 or 14 bolt and then sell your 44 to recoup some of the expense.

[69scout800]

Seeing that you're running 35's I doubt you'll save money in the long run by sticking with the D44. Build a 60 or 14 bolt and then sell your 44 to recoup some of the expense.
Then I can get that axle shaft back! :D

[Halfbox P]

According to a hot rod site I found through Google if I multiply my engine torque (290 FP) by my crawl ratio (28.77) and figure in 20 to 25% loss to the drive train I should have the potential to produce between 6675 and 6257 FP of torque at the axle. Making any of my options with the 30 spline result in broken axles. So it looks like I'll be building a 35 spline 60.

[ihojeff]

I don't get very many rear Dana44 custom axle jobs for a reason. Most go with a D60 because when its all said and done the D60 will cost you only $2-300 more than the D44.

[Shadow man]

I don't get very many rear Dana44 custom axle jobs for a reason. Most go with a D60 because when its all said and done the D60 will cost you only $2-300 more than the D44.


I also wonder how many of those people spent $1,000s many times over on a 44 or a 35 before they came to that ultimate decision?


I know a lot of people that took a long time to come to the realization that a 44 has its limits. :)

[Mechanos]

...my crawl ratio (28.77)...
That's not a crawl ratio, that's more like a run ratio.... or at least a brisk jog ratio. :flipoff2:

[Dalton Gang]

I have a rear D60 semi-floater out of an unknown donor/year truck. It is cut to Scout II width and has the Scout wheel flange's and a Detroit. The front is a Chevy D44 cut Scout II width with Warn premium axels and an ARB. I am running the stock 345/T-flite/D20 with 35 MT's. If I am not hammer'n on the throttle all the time, should this combo survive fairly well? Five years ago I thought this was a great combo, but now a 14/60 seems to be all the rage for worry free 'froading. I guess the main thing that concerns me is the rear. If something goes it might be hard to find someone with a spare D60 shaft cut Scout II length with a 5 on 5.5 wheel flange. Thanks

Brian

[BLK Scout 800]

I have still not had any issues with my front or rear...... 44's*chromo's*bobbylongs*38.5 14.5 sx's*tbi350*........did I mention it weighs 3,500lbs :)

[RustoleumWhite]

That's not a crawl ratio, that's more like a run ratio.... or at least a brisk jog ratio. :flipoff2:


:laughing: :laughing: :laughing: :laughing: :laughing: :laughing:

[472Scout]

I have a rear D60 semi-floater out of an unknown donor/year truck. It is cut to Scout II width and has the Scout wheel flange's and a Detroit. The front is a Chevy D44 cut Scout II width with Warn premium axels and an ARB. I am running the stock 345/T-flite/D20 with 35 MT's. If I am not hammer'n on the throttle all the time, should this combo survive fairly well? Five years ago I thought this was a great combo, but now a 14/60 seems to be all the rage for worry free 'froading. I guess the main thing that concerns me is the rear. If something goes it might be hard to find someone with a spare D60 shaft cut Scout II length with a 5 on 5.5 wheel flange. Thanks

Brian

Unless you're doing the extreme trails I'd say you'll be fine. Front joints are probably your weak link. Bad thing about that semi-floater is that if you bust an axle your SOL. With my FF rear if I bust an axle (or two) I can still get off the trail and probably home too.

[binderbound]

Granted, I have only had mine together for 9 months, but its held up fine. I like the clearance and the offset of the waggy rear. If I was to do it again, I probably would build a 35 spline 9" with a big passenger side offset.

I'm not too worried with all of 90hp and 4k of rust.

[Dalton Gang]

Unless you're doing the extreme trails I'd say you'll be fine. Front joints are probably your weak link. Bad thing about that semi-floater is that if you bust an axle your SOL. With my FF rear if I bust an axle (or two) I can still get off the trail and probably home too.

Thanks for the input. I did the Con with no breakage a couple of years ago with some other guys. I doubt I would ever doing anything more extreme than that. I guess it wasn't just luck that nothing broke.

Brian

[Eagle-Mark]

According to a hot rod site I found through Google if I multiply my engine torque (290 FP) by my crawl ratio (28.77) and figure in 20 to 25% loss to the drive train I should have the potential to produce between 6675 and 6257 FP of torque at the axle. Making any of my options with the 30 spline result in broken axles. So it looks like I'll be building a 35 spline 60.Wouldn't you have to divide that number by four? Even then you don't have to use all the power (foot to floor).

Plus you can find plenty of spare Scout II axles around, I've got two rears outside I have had for spares for four years... I think you'd be better off doing something with you crawl (run :D ) ratio first. I did everything in my Scout II at just above idle with the wide ratio t-19 and a Dana 300...