Let me share my thoughts on the high steer, and this is based on my experience only, but feel free to post up and discuss.....

I have seen studs shear, break and get loose, and this happens mostly on the ones that have the extra connection on the RH knuckle for the drag link....see image....

Vs this type arm, in which the drag link connects in an extra hole usually in the RH tie rod, like the OEM setup....

In the first style arm, (Lukes rear tie rod arms would fall in here also)
the stress of turning both front tires in transmitted via the 4 studs on the RH knuckle.....
On the latter, the stress is distributed thru all 8 studs equally....
I have the single hole on my truck, with the small pattern knuckles, and I check the studs, but rarely find any loose.......
Discuss......................
Butch

Butch:

I think you are right on the money. By connecting the drag link to the tie rod (or the front end of a high steer arm) the drag link pushes the tie rod which in turn pushes (turns) the steering arm and the knuckles. I do not think there is a whole lot of difference between the stock method of connecting the drag link to the tie rod, or slightly indirectly to the front of the steering arm. There is a minor leverage element in this latter connection style. I am suprised to hear that this difference has resulted in stud/knuckle breakage. The double steering arm concept of yester-year, and Lukes "rear steer", effectively use the passenger knuckle bearing as a fulcrum transfering the turning force from the drag link to the drivers side steering arm via the tie rod. This adds extra stress to the passenger knuckle, hence the propensity for the passenger studs to fail. The double steering arm added an extra stress as there is a twisting force on the passenger knuckle due to the fact that the tie rod and drag link are in different planes.

I have Luke's rear steer set-up and am happy with it - I like the idea of keeping the tie rod out of harms way. I have on my "to do" list upgrading the knuckle studs to the Dana 44 variety which, I believe, will mitigate the issue you raise above.

However, there is a lot to be said for regular hi-steer arms in the front.

I look forward to hearing other folks ideas and experiences....... This kind of topic gets uncomfortably close to LCML type discussions :D

Andy

Who sells the 2 hole version, I have been looking for some for my SOA 60

I dont really see how the two make a difference. You are still limited to how much force the tire is feeding back to the steering system. Unless you had deflection in the steering arm the only difference is you get an extra inch and a half or so of mechanical leverage on both tires because the drag link comes in out a little further. Both feed back to all 8 studs unless you had a loose or bad tie rod.

I personally dont have a problem with my studs coming loose. My tires are ballanced if that helps.

Maybe I'm wrong but I dont see it.

In the first style arm, (Lukes rear tie rod arms would fall in here also)
the stress of turning both front tires in transmitted via the 4 studs on the RH knuckle.....
On the latter, the stress is distributed thru all 8 studs equally....
I have the single hole on my truck, with the small pattern knuckles, and I check the studs, but rarely find any loose.......
Discuss......................
Butch

I agree with your analysis, but your case might have something to do with bunny trails...:flipoff2: :flipoff2: :flipoff2:

I think the problem is with the back spacing of the rim with wheel spacer's. All the broken stud's that I have seen had wheel spacer's and wide wheels.
We are pishing the limit of cruiser axle's with the new steering with tires over 35" lockers v8's, and low gears. When I had my wheels made I went with stock back spacing on 17x8 and so far know problem yet.

Texican, I think your theory is right on. This way you provide equal energy dispacement via the tie rod to the R and L steering arms. Otherwise, the R side gets full energy and the L takes a fraction.
This is how stock is done as well as my D44(No point).
Campy:cool2:

Nope, unless the DL is not tight, your theory does not hold water..

I think the problem is with the back spacing of the rim with wheel spacer's. All the broken stud's that I have seen had wheel spacer's and wide wheels.
We are pishing the limit of cruiser axle's with the new steering with tires over 35" lockers v8's, and low gears. When I had my wheels made I went with stock back spacing on 17x8 and so far know problem yet.

I agree with GFox and will throw scrub radius into the discussion.... OE knuckles are set with a scrub radius for stock offset wheels and stock tire diameter, which is what? 29, 30"s? Throw on wheel spacers, big offset or backspace wheels and larger tires and you can throw the scrub radius way off. The larger the scrub radius (in or out), the more load the arms take before the knuckles start turning, right?

I agree with GFox and will throw scrub radius into the discussion.... OE knuckles are set with a scrub radius for stock offset wheels and stock tire diameter, which is what? 29, 30"s? Throw on wheel spacers, big offset or backspace wheels and larger tires and you can throw the scrub radius way off. The larger the scrub radius (in or out), the more load the arms take before the knuckles start turning, right?

In the dark about scrub radius? :confused:

Tim, yep..


Scrub radius is the arc that your tire follows compared to the center of the kingpins (or ball joints)

The less Bs you have the more you have to "drag" the tire around. Vs pivoting the tire on a central point..

Tim, yep..


Scrub radius is the arc that your tire follows compared to the center of the kingpins (or ball joints)

The less Bs you have the more you have to "drag" the tire around. Vs pivoting the tire on a central point..

So in theory (not yet production), Marlin did it right with the six bolts by outboarding the two additional studs instead of inboard. Not only are you getting the additional stregnth of the two studs, the two studs somewhat compensate for the smaller BS and/or spacers? I understand the central point didnt change, but then for the scrub, it wouldnt make a bit of difference if the two additional studs were on the inside of the knuckle.

Tim, yep..


Scrub radius is the arc that your tire follows compared to the center of the kingpins (or ball joints)

The less Bs you have the more you have to "drag" the tire around. Vs pivoting the tire on a central point..

So in theory (not yet production), Marlin did it right with the six bolts by outboarding the two additional studs instead of inboard. Not only are you getting the additional stregnth of the two studs, the two studs somewhat compensate for the smaller BS and/or spacers? I understand the central point didnt change, but then for the scrub, it wouldnt make a bit of difference if the two additional studs were on the inside of the knuckle.

aw Mike. With those six bolt arms- you dont need to worry about any of that silly stuff. :D

Scrub Radius is the relation between the centerline of your tire and the King Pin Inclination. If the KPI hits the ground at the centerline of your tire, then you have no scrub radius. The closer the KPI is to the CL of the tire at the ground, the easier the tire will turn.

To find your KPI, you need to imagine a line through your trunions (king pins or ball joints) to the ground.

http://www.hedelands-motorklub.dk/GoKart/Teknik_-_Siden/Front_End_Geometry/Scrub_Radius.GIF

Cheesey drawing of a Go-cart set-up, but it works for the explanation.

I heard a rumor that the knuckle is caught in a legal tug-of-war between Marlin and Lord Valdemort!:eek:

This has me worried...

Scrub Radius is the relation between the centerline of your tire and the King Pin Inclination. If the KPI hits the ground at the centerline of your tire, then you have no scrub radius. The closer the KPI is to the CL of the tire at the ground, the easier the tire will turn.

To find your KPI, you need to imagine a line through your trunions (king pins or ball joints) to the ground.

http://www.hedelands-motorklub.dk/GoKart/Teknik_-_Siden/Front_End_Geometry/Scrub_Radius.GIF

Cheesey drawing of a Go-cart set-up, but it works for the explanation.

That will work for me and that is what I have been saying for years:smokin:

The two hole PS hi-steer arm does develop a slightly higher rotational moment about the KPI (thus shearing steering arm studs). I too think it has more to do with the increased scrub radius, contact patch (at low pressures too), steering upgrades, etc.

has nothing to do with shear. when the bolts are torqued down correctly it provides a clamping force. as long as both the knuckle, shims, and arms are clean, and the studs in good condition, they will not shear. I have never seen a sheared knuckle stud that wasn't a result of a loose arm. also the 2 holes on the passenger side I would beleive not to make a difference. it is not doubling the force unless you are hard on a rock forcing your right tire past the steering stop, and turning right at the same time. any other time, it is just the draglink sending it energy. then the energy is distributed between the 2 arms via the tie rod.

the one hole on each arm version to me creates a stress un-needed to the tie rod, especially when the suspension is in motion, forcing the centerlink of the tie rod to flex, and possibly giving the tie rod ends a pulling up and down motion as well as the side to side. causing pre mature failure. remember it will not be based on a normal vehicles suspension travel, because we are working with a lot more movement than any stock vehicle.
tighten your bolts, check them every trip, be happy.

Butch I agree with your train of thought except that my experience is exactly opposite.. Broken knuckle studs with my 4x4 labs setup and never a broken stud with a Marlin setup. Again like LCML nice comment there, I think it flat out has to do mostly with how tight they are IMO...

I was thinking the same thing as noodles, glad he posted so I don't have to type as much. :D
How I see it, is both systems will see the same force. Force coming from the p/s box or from the tire boucing off something. Like Noodles said, if anything, the drag link is pulling and pushing on the tie rod and is putting a twisting force on the knuckle plus the pushing and pulling force from the tie rod onto the knuckle.
I do see where the behind the axle tie rod setup could put more strain on the knuckle though, I agree with that.

has nothing to do with shear. when the bolts are torqued down correctly it provides a clamping force. as long as both the knuckle, shims, and arms are clean, and the studs in good condition, they will not shear.

Sure it does, what makes the connection fail. I know what leads to the shear, but assuming they are NOT 100% clean (as has happened 1000's) of times, then its all about the shear. Plus if you really get nit-picky, the shims themselves cause a very minute amount of potential moment on the studs themselves, they stretch, loosen the "clamp" and allow shear. Not 100% sure that is indeed the case, but considering the fact that aftermarket studs are improving the system, I would think this plays into the problem.

also the 2 holes on the passenger side I would beleive not to make a difference. it is not doubling the force unless you are hard on a rock forcing your right tire past the steering stop, and turning right at the same time. any other time, it is just the draglink sending it energy. then the energy is distributed between the 2 arms via the tie rod.

I don't assert that it is doubling the force, but I do think it adds more rotational moment to the PS arm, all proportional to the distance between the holes.

In the first style arm, (Lukes rear tie rod arms would fall in here also)
the stress of turning both front tires in transmitted via the 4 studs on the RH knuckle.....
On the latter, the stress is distributed thru all 8 studs equally....
I have the single hole on my truck, with the small pattern knuckles, and I check the studs, but rarely find any loose.......
Discuss......................
Butch

In layman's terms [for those of us with no engineering credentials!] I think you are saying that when you turn right for instance, the relay rod, as it ties into the passenger side tie rod end, is PULLING on the drivers side knuckle arm AT THE SAME TIME it is PUSHING on the passenger one, with a stock steering setup or a single-hole hi-steer. With a dual hole arm, the passenger side arm now has both jobs. Maybe too simplistic, but it makes sense to me.

As for the scrub radius issue TechTim explained, I have EXPERIENCED this without knowing what it was. I have NEVER had an issue with my knuckles on my 40 UNTIL I put on the custom widened rims before Rubithon04. Had spindle bolt issues at the Springs and, as I was walking around looking for donations of 8mm spindle bolts, Morgan Fletcher informed me that I had better check out the knuckle arms. HE WAS RIGHT! Even on 33's, scrub radius is a force to be reckoned with.

I am also glad that Kurt brought up the shim factor. I think it is significant as well.

Make sure the steering arms don't hit the springs...

I also use 4x4lab arms except I use the double arms with a hydraulic ram (PSC extream kit) going it the drivers side. My reason for doing this is to spread the force to bolth knuckles. So far everything is working great!

-Scott

Did Toyota adopt the larger knuckle bolt pattern when they introduced PS?

I haven't measured any of the after-market high steer arms, but If distance between the trunion bearing (axis) and the tie-rod hole are greater...then doesn't the amount of Torque also increase (think Seesaw)?

I haven't measured any of the after-market high steer arms, but If distance between the trunion bearing (axis) and the tie-rod hole are greater...then doesn't the amount of Torque also increase (think Seesaw)?
Yes...

I have the kongs setup with one ton stuff.

I may use the tie rod to drag link ends instead of both mounting to the arms.

IDEA!

Have you guys ever see a drivers side knuckle go????

All the pics I have seen are of the passenger side, so maybe there is some grounds for this theory.:p

Yeah, I can see how scrub radius could contribute to the issue. However, when you consider that without off-set rims and no significant scrub radius issues, there is still more force being transfered through the passenger side studs/knuckle than it was designed for with the set-up Butch is talking about. Studs break as a result of inadequate clamping force (improperly torqued/loose/stretched studs) between the knuckle and steering arm. The use of aired-down 35" and larger tires when wheeling along trails and forcing the front tires against obstacles is likely to be the major culprit contributing to stud failure. I doubt whether the correct (or minimized) scrub radius would aleviate this component of stress significantly. Just my non-engineering 2 cents.... :D

Just out of curiosity, how many folks have experienced driver-side stud breakage??

Q for Cruzilla: Your ram assist pushes the drivers side steering arm behind the axle? Got pics? Just curious about clearance issues with the ram and oil pan. Thx.

Andy

IDEA!

Have you guys ever see a drivers side knuckle go????

All the pics I have seen are of the passenger side, so maybe there is some grounds for this theory.:p

Yup, they go too. Had them go in South Dakota and Rubicon. I feel it was because of loose ones the first time and then because of repeated torqing, failed again. I finally had to install a helicoil, because the threads were fracturing. It is cast you know, and some pieces would come out, weakening the threads.

The force is applied to the tire that is against the rock. Usually the tire you can't see, the Passenger side takes more punishment because of the driver's inability to see it. I think the force is equal in that the drag link is hooked to everything. The difference may be in the point of contact. The two hole deal puts the rod further over thereby changing the ANGLE of the force applied. Cantelevering it over that way may put stress into the studs more than when the force goes through the tie rod, making it more lefty righty than at the angle of the drag link.

cruzila

Butch,
I have been saying this for years. I made my own high steer arms, factory arms cut, fliped and rewelded, gussetted. I use a modified fj62 tie rod and drag link set up ( 23mm just like the fj80) The drag link goes into the tie rod end and has had no failures to date. Installed on truck back in 1998, 8 years ago. I started off with 35x15.5 sx's on 12 wide wheels, switched to 36 sx's on 10" wheels, then 38.5x14.5 sx's on 10 wheels and 1.25 wheel spacers, now have 37 iroks on 10" wheels and 1.25 spacers. All this with factory 1985 studs, cone washers and bolts. AGAIN no failures and It has been wheeled hard.

Good luck to everyone.

Rob

Just out of curiosity, how many folks have experienced driver-side stud breakage??


Andy


I've only broken Drivers side studs on my 55. Twice, both times the outer two.

Rounded out the holes in the knuckle, so retapped for 1/2" and good to go.

My arms are single hole.

could it have something to do with the factory arms being cast? Two things with that, the metal will be ruffer so there will be more friction, and the metal will be a little harder so when you tighten the bolts there might be less give in the arms.
Like I said before I have never had any problems with my marlin arms.

For the reasons for breaking the passenger side only, speaking for myself I always tend to bind that tire more than my driver side because I cant see it.

Sure it does, what makes the connection fail. I know what leads to the shear, but assuming they are NOT 100% clean (as has happened 1000's) of times, then its all about the shear. Plus if you really get nit-picky, the shims themselves cause a very minute amount of potential moment on the studs themselves, they stretch, loosen the "clamp" and allow shear. Not 100% sure that is indeed the case, but considering the fact that aftermarket studs are improving the system, I would think this plays into the problem.



I don't assert that it is doubling the force, but I do think it adds more rotational moment to the PS arm, all proportional to the distance between the holes.
the only time in theory there will be shear is if the bolts are loose. they can be clean with brand new shims, available in the knuckle rebuild kits, the arms clean and the knuckles clean. I have air tools, my shtuff is clean.

in all reality I think the 6 studs arms and knuckles, the fact that there is a lrager clamping surface makes it better, and not the studs itself. or the arp studs that do not fatigue like the stocks.

Yeah, I can see how scrub radius could contribute to the issue. However, when you consider that without off-set rims and no significant scrub radius issues, there is still more force being transfered through the passenger side studs/knuckle than it was designed for with the set-up Butch is talking about. Studs break as a result of inadequate clamping force (improperly torqued/loose/stretched studs) between the knuckle and steering arm. The use of aired-down 35" and larger tires when wheeling along trails and forcing the front tires against obstacles is likely to be the major culprit contributing to stud failure. I doubt whether the correct (or minimized) scrub radius would aleviate this component of stress significantly. Just my non-engineering 2 cents.... :D


You are very correct, things need to be clamped together properly, however an axle and wheel/tire set-up for proper scrub radius will need less load to turn than one with big scrub radius.

Also a taller tire on the same 3"BS wheel and 1.5"spacers will have less scrub radius than a shorter tire of equal width will turn easier and also put less stress on the knuckle and studs. Example 33" MTR vs 40" MTR on same rim and spacer combo. Damn I have to go buy some 40s now.

Nice theory, but it is not really true..

40's will typically have a larger contact path and more friction to turn..

Not long after installing Luke's set up, I had a driver side stud break. I think it was from not being tightened enough from the start. The sure solution to this whole problem is to ditch power steering all together, therefore eliminating the excessive forces to the knuckles. I vote that Butch does this first and keeps us updated on any breakage or lack of.:flipoff2:

Someone needs to make a keyway for the knuckle and arm that would fix it.

usually drivers side break half as much as the passenger side due to the ideas texican noted. 6 bolts are great but salty in my taste. Drill the hole to 9/16's dana 44's add the 5th bolt and your done. Problem solved. Backspacing spacers,water whatever all become a non issue

5th bolt?

http://www.pirate4x4.com/forum/showthread.php?t=342698&highlight=5th+bolt

The sure solution to this whole problem is to ditch power steering all together
power steering is overrated :D

Yeah, I can see how scrub radius could contribute to the issue. However, when you consider that without off-set rims and no significant scrub radius issues, there is still more force being transfered through the passenger side studs/knuckle than it was designed for with the set-up Butch is talking about. Studs break as a result of inadequate clamping force (improperly torqued/loose/stretched studs) between the knuckle and steering arm. The use of aired-down 35" and larger tires when wheeling along trails and forcing the front tires against obstacles is likely to be the major culprit contributing to stud failure. I doubt whether the correct (or minimized) scrub radius would aleviate this component of stress significantly. Just my non-engineering 2 cents.... :D

Just out of curiosity, how many folks have experienced driver-side stud breakage??

Q for Cruzilla: Your ram assist pushes the drivers side steering arm behind the axle? Got pics? Just curious about clearance issues with the ram and oil pan. Thx.

Andy
many times with my 42,s

KrustyKruiser,
The ram mounts on the front of the axle, bolth steering arms are the same, the drag link connects to the pasenger side and the ram connects to the drivers side, the tie rod is behind the axle above the pinion. Go to 4x4Labs and look at his stuff there, I think he has pics of the double arm system.

-Scott

Ran 38.5 swampers for 5 years with stock mini birfields, knuckles, and hysteer ( 1 ton), single hole on passenger side, on my 1973 FJ40 with no breakage at all. Put the Ranger high strength studs on the knuckles last year. Put ARB in front this year and had a make believe birfield breakage that turned out to be the parking brake drum backing plate sheering off. :rolleyes: Yea, I will never live that one down:laughing:

My question is, does retorquing the studs to specs put too much pressure on them, causing them to break prematurely?

Something that was mentioned, not really addressed much, but I think is significant to this discussion...

Slop in the joints, be they TRE's, heims, etc...

You turn the wheel, and on a 2-hole setup, there are 3 slop points initially: pitman arm joint, drag-link-to-tie-rod-joint, and then each joint at the steering arm. ASSuming that both joints at the steering arms wear equally, equal force will be applied to the steering arm/knuckle when the wheel is turned.

With a 3-hole setup, you still get the pitman slop and the drag-link to steering arm slop, but now, *any* slop in the tie-rod's 2 joints (1 at the RH steering arm, the other at the LH steering arm) will mean that the right side steering arm/knuckle will be getting torque while the left side is not, because the movement is being absorbed by taking up the slop in the 2 joints on the tie-rod.

An analogy would be birfs... get stuck in a hole. if 1 tire is in the air, the other one will now see more torque, because the tire in the air isn't sharing the load.

Whaddya think?

If your TRE's are loose, you have not been paying attention well enough. And your steering arms are probably very likely going to fall off soon.


TRE's are tapered. So they fit very snugly into the socket. Besides, if the TRE's are loose, they typically tell you ;)

Best solution , with oem tre's and tie rod on a 3.5 bs wheel the tre's are so close to the rim that they rub when the steering arm studs get loose and let the arm flex. If you know the noise you will know when the studs are loose and grab the 17 mm box end under yoyr seat and tighten them. Those who run no wheel weights on the inside front rim know. The tre's usually have a hole worn in one side of boot from rubbing rim.

ps , thats with 1/4 in. spacers on the front.

Jason, I think Eskimo meant the slop IN the TRE. You know a worn one. They have to have space to move right?

I still think the wheel that can't be seen takes the abuse just because of that fact. The wheel that is bound up will see all the "force" when you turn your wheel. It has to push the wheel, axle and some of the weight of the rig. The side that is not bound up will not see the weight of the vehicle on it.

Not only does the wheel that can't be seen get all of the abuse, but also the fender on the passenger side. I have a tough time with the passenger side fender on my 40. Smashed it, bent it, layed it back, and just plain crumbled it. :rolleyes:

Not only does the wheel that can't be seen get all of the abuse, but also the fender on the passenger side. I have a tough time with the passenger side fender on my 40. Smashed it, bent it, layed it back, and just plain crumbled it. :rolleyes:


Me too. Then I got MT fenders and have only tapped them on a few things. Kinda a little disapointed. I have tried to nail them on a rock to see how they do but havent got them too bad yet. Should get in on the order right now.

IDEA!

Have you guys ever see a drivers side knuckle go????

All the pics I have seen are of the passenger side, so maybe there is some grounds for this theory.:p

Yes, on my D60 because the studs were loose.

Someone needs to make a keyway for the knuckle and arm that would fix it.

I know of at least one party working on it... in time I'm sure we'll see more of it. ;)