rear axle beef

[mookie]

just wondering why someone doesn't make a spool or locker for a stock landcruiser rear axle that would accept 35 spline axle shafts or axle shafts that are the same thickness from the wheel end to the diff end, whatever spine count that would turn out to be? similar upgrades are available for dana 44 and dana 35 axles

[lowtideride]

Originally Posted by mookie

just wondering why someone doesn't make a spool or locker for a stock landcruiser rear axle that would accept 35 spline axle shafts or axle shafts that are the same thickness from the wheel end to the diff end, whatever spine count that would turn out to be? similar upgrades are available for dana 44 and dana 35 axles

I dont think spline count has a whole lot to do with it. The axle shafts neck down right at the splines and thats where they always break. If you could hog out the carrier allowing you to run larger axle shafts that would not neck down right at the splines. I think that would help more than just increasing spline count. Look at 14 bolt or D60 axle shafts both have 30 and can take a rather good pounding. Just my 2 cents though...

[muddogbob]

http://forum.ih8mud.com/hardcore-cor...line-rd33.html

spline count does matter.

[Eskimo]

To increase spline count you'd be increasing the diameter, which would take care of your necking down concern

Mind you, I'm running wimpy 16 spline shafts..

[mookie]

well that's what i was trying to say- make an axle shaft that is uniform in thickness, from one end to the other- the big ass, beefy size that the stock shafts are on the wheel end- the largest end and then make a locker or spool that would accept an axle shaft that diameter

[Mace]

Originally Posted by mookie

well that's what i was trying to say- make an axle shaft that is uniform in thickness, from one end to the other- the big ass, beefy size that the stock shafts are on the wheel end- the largest end and then make a locker or spool that would accept an axle shaft that diameter

And would break faster than a shaft that was designed properly with a reduction in diameter..

completly straight shafts are not the strongest design..

BTW, ARB is broaching side gears to accept 35 spline shafts.


Course, then you have to deal with a narrow and weak axle housing..

[lowtideride]

Originally Posted by muddogbob

http://forum.ih8mud.com/hardcore-cor...line-rd33.html

spline count does matter.

True spline count does matter but if the axle is only a little over an inch thick its not going to do much

[Mace]

Generally the number of splines defines the diameter of the shaft. (fine spline)

There are exceptions (14 bolt), but for the most part, a 35 spline shaft is gonna be larger in diameter than a 30 spline shaft.

Stock 30 spline D60's shafts are no stronger than a 40's axle shaft is..

[lowtideride]

Originally Posted by Mace

Generally the number of splines defines the diameter of the shaft. (fine spline)

There are exceptions (14 bolt), but for the most part, a 35 spline shaft is gonna be larger in diameter than a 30 spline shaft.

Stock 30 spline D60's shafts are no stronger than a 40's axle shaft is..

I was not saying adding to the spline count wont make it stronger. I was saying the problem is that the axle shaft necks down right at the splines. The axle size I feel is just to damn small where it necks down(where the splines are). I just dint feel adding 5 more splines to the shaft would make it that much stronger. But I guess if you are adding splines the axle has to be larger.

[mookie]

Jesus H.... i thought it would be pretty obvious that when i said increase the spine count that i meant that the axle diameter would therefore be larger...duh

and i find it Very hard to believe that an axle shaft that was as freaking big on both ends as the stock shafts are on the wheel end would be weaker than the stock tapered rear axle shaft, i mean it necks down to like one inch where it goes into the diff...

[Sputnik40]

All gets so befuddling. Al, Mace and Eskimo are well ahead of us here with the 14 bolt, D60 and oh yeah those wimpy RW 14 splines .

Al - remember that the Poly axles were far skinnier than the stock Cruiser axles - ads some visual to Mace's comment on downside of straight shaft (engineering). Although with the comment that a D60 30 spline is roughly the same strength as a stock 30 spline - leaves me wondering where I'm at having busted that Poly axle?

Spline count - think there's a good article somewhere that clarifies exactly what everyone's saying. Notwithstanding older course spline jobs, almost all newer stuff built for strength has a diameter that goes up with spline count. Kinda a common sense thing.

ARB broached side gears - I'm a big fan of the Krawler mag write up on what's his name's Raisen at Slee OR. Diamond housing using a OEM electric locker diff (sans locker), machined bearings to accept 35 spline Dana 60 axle conversion kit (full float style bearing retainers with 6 wheel studs) and lincoln locker welded 35 spline side gears. Called to discuss if they might help piece a kit together, didn't get far and have too little time and money to pursue it...

[Tapage]

All cruiser axles that I saw broken are tin the place ( and the longer side in my case ) just at the spline .. does the longer axle support more torsion and then can handle more torque . ?

[Bret]

It may have to do with the amount of twist the axle can handle before it gives. If a flexible axle sees a shock load, the twist flex in the axle helps absorb the stress and dissipate the load over time. kinda like the EPS foam in a motorcycle helmet. When a larger more rigid axle sees a shock load there may be less flex which could mean a larger load over a shorter time seen at the splines. Of course I'm guessing and there are many more variables to consider, so who knows...

[Mace]

Now we are getting into the differences between axle shafts.

The problem with these discussions is that there is no real level playing field.

A GM 60 is 30 spline, same as a LC. The shafts are different in design than the LC shafts. But they are heat treated differently as well. So they break about as easily even thought hte shaft is a slightly better design. (taper).

The PP shafts are a better material, and a better design than the LC stuff. But, since you are dealing with a relativly heavy rig and still have the 30 spline limitations they will break.

Aftermarket shafts may start out as a blank (same radius all the way to the end) and then have the spline cut into the shaft. Not a great design. You can easily cut through the hardened exterior of the shaft and create an axle that may indeed be weaker than a stock shaft.
Rolled splines typically have a root diameter of the splines that is about the same diameter as the narrowest portion of the axle shaft. Look at a stock front shaft (seal portion excluded).

So much goes into what makes an axle shaft "strong" it is silly.

Neat topic tho..


We need pics and an engineer

[muddogbob]

Pirate4x4.Com - Extreme Four Wheel Drive

[muddogbob]

Originally Posted by Tapage

All cruiser axles that I saw broken are tin the place ( and the longer side in my case ) just at the spline .. does the longer axle support more torsion and then can handle more torque . ?

Longer axles can handle more torsion than shorter shafts. They allow more twist before deformation.

[Poser]

Originally Posted by Mace

Aftermarket shafts may start out as a blank (same radius all the way to the end) and then have the spline cut into the shaft. Not a great design.

My CTM 1.5" 35 spline rear axles seem to be doing just fine....

[mookie]

do full floater type axle shafts have the same diameter from one end to the other or do they taper down in the middle and then taper back out or what?

there are aftermarket lockers and axleshafts that do exactly what i'm talking about for dana 30&35 (increases spline count to 30) and for dana 44 (increases spline count to 35) i just don't understand why we can't get a product like this for our axles unless there's just not enough demand for it...

[Sputnik40]

Originally Posted by Poser

My CTM 1.5" 35 spline rear axles seem to be doing just fine....

Enlighten me - what do those shafts go in ?

Engineering design - torsion is obviously a factor - the Poly axle I busted had some minor twisting at the splines, but it grenaded a 1/3rd of the way down - you can see a much longer crack on either side, but when it went you can see how the outer harder material reacted differently than the softer inner.

So - I would surmise that the best way to ensure shaft strength is to create it as it will be used - will minimal to zero milling. Yes - I'm sure that further heat treating or other strength creating improvements will help, but it's like a forged wheel - you want the metal aligned and weighted in specific places to provide the desired engineered torsion and strength.

As a sidebar - surfboard blanks are the same except that you can't treat them further after you shape them down. So when you buy a blank to shape, you want it to be as close as possible to the final shaped down design - that way you retain the harder exterior which aides in overall structural integrity and longetivity, as well as exterior tuffness (meaning you can run lighter glass).

Good conversation.

[Mace]

CTM's are a stupid strong shaft. Jack really does like to use the best materials he possibly can
You happen to have a preinstall pic?

And steve has a tru hi 9" rear axle.

bit of a strength upgrade over a LC axle

[Mace]

BTW, Billa's axle shaft tech is an awesome article..

[Medusa]

You can get an axle shaft made any way you want it....as long as you are willing to pay for it. Give Jack Graef at CTM a call. A major problem with a semifloating axle is that it becomes prohibitively expensive to make a billet shaft from high quality material like 4340 or 300M

Like Poser, I am pretty happy with my 300M CTM fullfloating shafts, even though they are such an inferior design In fact, I think a D60 with these shafts is about the best compromise for strength and cost.

[Mace]

Originally Posted by Medusa

even though they are such an inferior design

Ohh stop it...

Material selection is just another part of making a shaft strong.

Jack, do you have a good pic of either end?

[Sputnik40]

Originally Posted by Mace

CTM's are a stupid strong shaft. Jack really does like to use the best materials he possibly can
You happen to have a preinstall pic?

And steve has a tru hi 9" rear axle.

bit of a strength upgrade over a LC axle

So to get back to the original post - now that we have the larger bearing race 3rd's available (e.g. late model FJ80 electric locker diffs), why doesn't someone make a spool with modded bearings for the carrier - that can accept a larger 35 spline axle shaft!

He has a good point. I'd want one, with some 1.25" 35 spline poly axles to go with .

[Mace]

Spool and C clip axles do not go well together.

[LC_Hamma]

Originally Posted by Sputnik40

So to get back to the original post - now that we have the larger bearing race 3rd's available (e.g. late model FJ80 electric locker diffs), why doesn't someone make a spool with modded bearings for the carrier - that can accept a larger 35 spline axle shaft!

He has a good point. I'd want one, with some 1.25" 35 spline poly axles to go with .

Order a pair of X32010X bearings (same as ARB RD33 35 spline conversion) & send Jack your side gears so he can anneal, rebroach & heat treat 'em. Don't know how much mat'l will have to be machined off the elec. lockers flange caps Heck, I'd send him the whole 3rd so he can inspect before machining.