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General Tech How would you build a rear steer axle?

Greg

Greg

Make RME Rockcrawling Again!
Admin
Location
Grand Junction, CO
If you were to build a rear steer 'drag axle' for a crawler with sticky 40" tires how would you build it and with what parts? (Real world like you were actually doing it, not a top-dollar parts like 40 spline gun-drilled axles and a trophy truck 10" axle.)

I think there are 4 main components to consider;

  • Center section
  • Knuckles & Hub
  • Steering setup
  • Shafts & Joint

Center section; I really like my Dana 70U rear axle with it's smooth bottom, but locker choices are limited. Not a 14 Bolt fan either. It would be awesome to use a Tera 60 housing with tubes welded in and blank ends, like @N-Smooth is building for his buggy. I think the E350 rear Dana 60 has a smooth bottom too. Are there any e-lockers that work good and don't have issues?

Knuckles and Hub; I think a SuperDuty knuckle and unit bearing parts get the nod here, probably best to upgrade to an aftermarket knuckle though? I understand that the SD steering parts are close to 8" wide each, so that's good info.

Steering; I really like my 2.75" PSC DE steering cyl, it has plenty of power pushing around 40" tires even when bound up. A TC pump seems like the highest flowing option. What I don't know about is controlling the steering, centering it, etc.

Shafts & Joints; 4130 alloy shafts for sure & beefy aftermarket u-joints. Would 35 spline with quality parts be enough? Looks like 1550 joints and 40 spline stub shafts are readily available but $$$$, drive flanges would be a must.


What else am I missing? Ball joints? Tube size for SD steering parts?
 
N-Smooth

N-Smooth

Smooth Gang Founding Member
Location
UT
I’d do a fabricated 9” housing from Trail Gear and do a Hi-9 or tube works diff. And ARB or Zip locker. It’s expensive but you’ll only have to do it once. Then probably 99-04 SD stuff because of aftermarket shaft availability. Superjoints of course. 3” rams are the best, @Agility Customs had the numbers for how much more powerful they are than a 2.75” and it’s pretty staggering IIRC. The rear end sees a lot of forces when you get bound up going uphill so it’s worth it IMO.
 
YROC FAB.

YROC FAB.

BUGGY TIME
Vendor
Location
Richfield, UT.
G-Smooth said:
If you were to build a rear steer 'drag axle' for a crawler with sticky 40" tires how would you build it and with what parts? (Real world like you were actually doing it, not a top-dollar parts like 40 spline gun-drilled axles and a trophy truck 10" axle.)

I think there are 4 main components to consider;

  • Center section
  • Knuckles & Hub
  • Steering setup
  • Shafts & Joint

Center section; I really like my Dana 70U rear axle with it's smooth bottom, but locker choices are limited. Not a 14 Bolt fan either. It would be awesome to use a Tera 60 housing with tubes welded in and blank ends, like @N-Smooth is building for his buggy. I think the E350 rear Dana 60 has a smooth bottom too. Are there any e-lockers that work good and don't have issues?

Knuckles and Hub; I think a SuperDuty knuckle and unit bearing parts get the nod here, probably best to upgrade to an aftermarket knuckle though? I understand that the SD steering parts are close to 8" wide each, so that's good info.

Steering; I really like my 2.75" PSC DE steering cyl, it has plenty of power pushing around 40" tires even when bound up. A TC pump seems like the highest flowing option. What I don't know about is controlling the steering, centering it, etc.

Shafts & Joints - 4130 alloy shafts for sure & beefy aftermarket u-joints. Would 35 spline with quality parts be enough? Looks like 1550 joints and 40 spline stub shafts are readily available but $$$$, drive flanges would be a must.


What else am I missing? Ball joints? Tube size for SD steering parts?
Click to expand...
check out how we are doing austins queer steer axle. i belive it is the best, cheapest, and strongest route. https://www.rme4x4.com/threads/the-trailantula.119898/
 
YROC FAB.

YROC FAB.

BUGGY TIME
Vendor
Location
Richfield, UT.
G-Smooth said:
Bla Bla Bla

Shafts & Joints - 4130 alloy shafts for sure & beefy aftermarket u-joints. Would 35 spline with quality parts be enough? Looks like 1550 joints and 40 spline stub shafts are readily available but $$$$, drive flanges would be a must.
Click to expand...
Ive broke 3 out of 4 of my 35 spline chromoly shafts in my "light" single seat buggy. Id definitely go 40 spline inners if i did it again.

Skip the 40 spline stub shafts and drive flanges and get the coke can sized 32 spline stubs. More parts more problems.
Huge sexy stub shafts
More huge sexy stub shafts
 
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YROC FAB.

YROC FAB.

BUGGY TIME
Vendor
Location
Richfield, UT.
N-Smooth said:
I’d do a fabricated 9” housing from Trail Gear and do a Hi-9 or tube works diff. And ARB or Zip locker. It’s expensive but you’ll only have to do it once. Then probably 99-04 SD stuff because of aftermarket shaft availability. Superjoints of course. 3” rams are the best, @Agility Customs had the numbers for how much more powerful they are than a 2.75” and it’s pretty staggering IIRC. The rear end sees a lot of forces when you get bound up going uphill so it’s worth it IMO.
Click to expand...
99-04 stuff is limited to 1480 u joint size. The newer 05' stuff is impressively larger and will fit 1550 size joints and or a rockwell sized RCV Bell.
 
YROC FAB.

YROC FAB.

BUGGY TIME
Vendor
Location
Richfield, UT.
G-Smooth said:
Bla bla Bla

Steering; I really like my 2.75" PSC DE steering cyl, it has plenty of power pushing around 40" tires even when bound up. A TC pump seems like the highest flowing option. What I don't know about is controlling the steering, centering it, etc.

What else am I missing? Ball joints? Tube size for SD steering parts?
Click to expand...

3" ram is what most run on Rear applications. When you climbing steep stuff all the wheight goes to the rear and ive heard of people running smaller rams having them not be able to hold the wheels pointed where you want them.

Your gonna want some bj eliminators if you run the sd stuff. We have ran the busted knuckle upper ball joint elimitors with great success. 1.5" .25 wall dom is what ive always made my steering links out of. Im going to run 1.25".25 wall on my next build.
 
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YROC FAB.

YROC FAB.

BUGGY TIME
Vendor
Location
Richfield, UT.
G-Smooth said:
Knuckles and Hub; I think a SuperDuty knuckle and unit bearing parts get the nod here, probably best to upgrade to an aftermarket knuckle though? I understand that the SD steering parts are close to 8" wide each, so that's good info.
Click to expand...
The bj sd knuckles are a cast steel that you can weld your high steering parts right to. I have built and wheeled with lots of buggys that just have them welded on with no problems. several venders offer weld on kits. Busted knuckles look to be the beefiest. See what kind of steering akerman angles and what kind of angle X ram length will get you. Austins will have a neutral akerman angle and turn 45* with the 9" ram we are outfitting.
 
YROC FAB.

YROC FAB.

BUGGY TIME
Vendor
Location
Richfield, UT.
G-Smooth said:
Bla bla bla queer steer.
What I don't know about is controlling the steering, centering it, etc.
Click to expand...
You can have manual rear steer hydralic valve or an electric one with a self centering selinoid setup. Austin ran the electic valve setup on his big buggy and it was pretty trick for it to self center with the flip of a switch. I dont know where he got that valve. @_Auzzy_
 
RockChucker

RockChucker

Well-Known Member
Location
Highland
I’ve been looking into a really digging the Toyota 10.5 axle of late. If I catastrophically explode or bend my smooth bottom E350 rear d60, I’ll probably put one of those in. Low pinion, but the hypoid offset is much less than most Dana axles. The pinion seems to be shorter than d60/70 stuff as well. Aftermarket housings are available and has been mentioned…05+ super duty stuff for the wheel ends. That leads to the question of setting caster. What do you set it to? Couple degrees positive? Meaning top of the knuckle trailing the lower like a front axle?
 
spaggyroe

spaggyroe

Man Flu Survivor
Location
Lehi
Greg, when I had my big buggy, I built my own return to center function and it was a nice novelty to have but I found it to be unnecessary in the real world. If the rear is turned much, you can easily feel it and manually adjust. If its turned just a tiny bit, you really don't even notice.

If I were to do it over again, I wouldn't worry about a return to center function. Just my $.02
 
Agility Customs

Agility Customs

Well-Known Member
Vendor
After building tons of rear steer axles the last few years, I would do a 9" with superduty outers and a 3" ram. The fabricated center section makes it way easier to mount the ram and it just looks cooler. 9" parts are cheap enough that its not a bank breaker. There is also no need to go aftermarket knuckles on the superduty stuff
 
_Auzzy_

_Auzzy_

Current Rig: 12W Boots
Location
Richfield Utah
G-Smooth said:
If you were to build a rear steer 'drag axle' for a crawler with sticky 40" tires how would you build it and with what parts? (Real world like you were actually doing it, not a top-dollar parts like 40 spline gun-drilled axles and a trophy truck 10" axle.)

I think there are 4 main components to consider;

  • Center section
  • Knuckles & Hub
  • Steering setup
  • Shafts & Joint

Center section; I really like my Dana 70U rear axle with it's smooth bottom, but locker choices are limited. Not a 14 Bolt fan either. It would be awesome to use a Tera 60 housing with tubes welded in and blank ends, like @N-Smooth is building for his buggy. I think the E350 rear Dana 60 has a smooth bottom too. Are there any e-lockers that work good and don't have issues?

Knuckles and Hub; I think a SuperDuty knuckle and unit bearing parts get the nod here, probably best to upgrade to an aftermarket knuckle though? I understand that the SD steering parts are close to 8" wide each, so that's good info.

Steering; I really like my 2.75" PSC DE steering cyl, it has plenty of power pushing around 40" tires even when bound up. A TC pump seems like the highest flowing option. What I don't know about is controlling the steering, centering it, etc.

Shafts & Joints; 4130 alloy shafts for sure & beefy aftermarket u-joints. Would 35 spline with quality parts be enough? Looks like 1550 joints and 40 spline stub shafts are readily available but $$$$, drive flanges would be a must.


What else am I missing? Ball joints? Tube size for SD steering parts?
Click to expand...

Sorry about your bias to 14B's but in all reality for packaging, aftermarket, information, strength and availability they cant be beat. The way @YROC FAB. and i built mine its got a super smooth and tough belly now.

- I agree with the knuckle/hub combo. 05+ are easily available, researched, and some cool cheap tricks available to make them last. American Iron Offroad makes a BEEF Aftermarket inner C that i really debated going with for two reasons. A- being they come in the two common tube sizes, 3.5" & 4" which means you wont need an adapter spacer like i needed with a OEM C. Reason B is the sheer beef of them. but its all in your budget, there's companies out there that make weld on gussets for OEM's like 44's and such but from what I have researched it actually takes quite a bit of carnage to F one up in which case you are gonna have bigger issues to worry about.

- Steering wise it depends on a lot of variables. what angle would you like to achieve? what kind of pump are you running? what is your rear valve specs? are you running a single pump for both rams or running a dual pump setup? I had a beefed up P pump from Lee's Steering out of Cali running both and it did all right but it did lag a little even though it was spec'd for 1800psi and 6gpm but that was only at higher rpms. i had PSC 3x9s on both ends with a 11gpm electronic valve with a RTC kit from Leeroy Latham, loved that kit! the valve was an eBay special that worked fine. for a orbital i had a 250MIL From Rockwell Offroad. All these will effect your happiness with the setup. another option is looking at an electric kit. I originally had one and i loved its feedback and it was torquee! it would shove the rear end around with the buggy standing up with ease but it was slow. from my understanding Leeroy revamped his kit and found a better fitting pump that was strong and quick so that might be a good route if you got the space for the pump and a good alternator. another big win for me with it was i once had my steering pump shaft snap and lost my front end but i was able to be towed home by holding the front steady and using the rear to steer.

- Shaft & Joint wise just go ahead and step to the 40 splines with 1550s and from a good name. buy once, cry once and be done with it. The rear shafts get a lot more abuse than a front so people saying their front 35's have held just fine over the years is not a fair comparison. in a straight normal rear shaft, sure its fine, but add in the torque load from turning/binding and its a lot greater. for the 14bs the crane seals are the go to for it. Theirs offers quality seals that can be locally sourced and will fit a 40.
 
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ChestonScout

ChestonScout

opinions are like Jeeps..
Location
Clinton, Ut
spaggyroe said:
Greg, when I had my big buggy, I built my own return to center function and it was a nice novelty to have but I found it to be unnecessary in the real world. If the rear is turned much, you can easily feel it and manually adjust. If its turned just a tiny bit, you really don't even notice.

If I were to do it over again, I wouldn't worry about a return to center function. Just my $.02
Click to expand...
I 100% disagree with this. I rely on my return to center completely.

Rear steer can get you in trouble in a hurry.

SUPER slow crawling it is not as important but I still use it. Moving at any speed at all it makes you look like a way better driver than you actually are.

Leroy makes a simple kit that runs with a cable connected to the axle and the sensing unit can be put anywhere. It has been flawless for 8 years.
 
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