DeftwillP
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- Location
- Round Rock TX
Can a thread be nominated?
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Sent from tapatalk on iJunk
Iron Rock Long Arm Upgrade
- Thread starter 98XJLimitedNateWV
- Start date
no no, I'm just saying his basis for suggesting a 5/8" bolt as minimality sufficient had no supporting information. You're also jumping your XJ... So considering your application (use of the vehicle) it would suggest a 10mm bolt is not an option. I'm suggesting that IRO has not lost their morals for road safety by producing this kit.
I also feel the hardware used for the top links in a 4-link are subject to different stresses. You're upper links transfer impact into your chassis mounts. IRO's third link can only direct that into the lower tube as it rises back to the cross member. Not to mention as your suspension travels through its range of motion, that stress on those upper links/hardware changes; correct?
(please be mindful that I am not attempting to compare the strength of your setup to IRO's; this is merely an example to illustrate there are differences.)
scottmcneal
NAXJA Forum User
- Location
- not here
No i'm not. I think you did.Read it again, but this time put a smile on your face.You know, it's called humor. LOL. I just think of 2 years of this is silly, don't you?
DeftwillP said it best
Can a thread be nominated?
One would hope so.Now go out and wheel folks, life is way to short.
XJLI
NAXJA Forum User
- Location
- Long Island, NY
iFail
- Location
- San Diego
just because i like to play devils advocate, but whats your supporting information for thinking the single 10mm bolt is indeed enough? and what is the minimum size that should be used? when is a larger bolt required? after trial and error?
I post here between loading large assembly models at work. That's why none of my post happen outside of work hours, lol. I'm too busy in the garage, out on the trails, or on the track.
Sheer strength, b/c that's all I can provide. I do not have the means/time to assembly a fixture capable of measuring rotational force applied to the axle mount within this long arm system. I assume neither did they and that this bolt selection was a product of trial & error. I still think the forces applied to that bolt/link are different that those within a 4-link. It can only redirect load into the lower link.
scottmcneal
NAXJA Forum User
- Location
- not here
LOL..I just started reading the first post and was thinking when i looked at the date of it.Carry on guys, i just think we need to smile more and wheel a hell of alot more thats all.You all go back at now.Enjoy your day
scottmcneal
NAXJA Forum User
- Location
- not here
Nope, just poking fun.Have a great day.By the way, i'm right and so are you, i think.LOL
vetteboy
NAXJA Forum User
- Location
- morganville, nj
For what it's worth:
- my XJ spends very little time, if any, in the air. I can't steer when the tires are off the ground, and steering is a pretty big part of racing.
- shear strength should not even be a part of this discussion. If it is, something has already gone wrong in the joint.
- again, before I go dig up more numbers, what do you feel is a suitable design factor of safety for the strength of that single 10 mm bolt?
- links can only transmit force axially along their length.
s14unimog said:
I'm sorry, I really don't understand this 'different stresses' idea. People have also had 10mm bolts fail when used in a trackbar application. It's different things that may cause the stress, but at the end of the day, it's the magnitude that matters, no?
XJLI
NAXJA Forum User
- Location
- Long Island, NY
:laugh2:
- Location
- San Diego
this is because of the clamping force correct? the friction between the bushing and arm takes away from the bolt experiencing most of a shear load? so then would it be the sudden shock of a bit hit that exceeds the friction of the clamping force and quickly transmits the energy to the bolt in shear causing it to potentially break? if im wrong please say so. im just curious and trying to learn.
^ how is that hard to understand. When a 4-link based system see an impact to the axle the forces are distributed into the links. The slack or tolerance of the assembly will be removed in the direct of force, and the hardware will come under shear forces; although, minuet differences in link lengths and hole tolerance will concentrate forces unequally across the system. In the IRO system it seems all three connections hardware will again come under shearing loads except the rotation of the axle, which is the only direction the axle can push load into that upper bolt independently (since if moved in any other direction, the lower M14 would share) would be sent into the side of the lower link, hence the gusseting. It is my opinion that the loads under the same identical impact would not be equal to those upper bolts in a 4-link assembly are subject to. You have to remember the two connections on the drivers side cannot move independently.
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vetteboy
NAXJA Forum User
- Location
- morganville, nj
OK...we'll keep going with this.
If you believe this statement, then you believe that tightening the nut does nothing. Might as well just throw a 10mm hitch pin through there and call it good, right?
Tightening the nut places the bolt in tension, which creates clamping force across the bolted interface. This force creates friction between the parts, which is *really* what holds your parts together, and the tightening torque is a function of how much clamping force you can create before the bolt is stretched into plastic deformation.
If that bolt loosens up, or if the mating area between the surfaces isn't clean or even, then yes, the bolt is loaded in shear as well. It might continue to work for a while like that, but that's never the design intent.
If, as you say, the only force that upper link sees is from controlling axle wrap/braking torque, it should be easy then. Isn't the torque limited by either a) the friction of the tires on the ground or b) the weakest component in your drivetrain? From there it becomes a simple free-body diagram of torques and the reaction forces.
If the front tires are gripping with a coefficient of 0.9, say during braking, and you've got 2500 lbs over the front end, that's a reaction force of 2250 lbs at the tire contact patch. Figure a 35" tire with a 17" rolling radius and the net torque applied at the axle tube center is just over 3100 ft-lbs. If that single upper bolt is the only thing reacting that much torque, what's the loading on it become? Keeping in mind that the upper link isn't acting perpendicular to the reaction force, so the loading on that joint is increased even more to compensate.
(see above regarding transmitting force to bolts in shear loading)
In order to make your argument more clear - better define this 'impact' you're talking about. What direction is it coming from? What component on the truck is receiving that impact first? What's the real-life scenario you've got in mind?
Also, to put it in perspective, I've also broken a lower 9/16" bolt (approx. equivalent to your M14), which is still smaller than the 5/8" bolt I broke. And if it matters, that 5/8" bolt was in one of the rear uppers, not a front.
Just trying to explore reality here.
If you believe this statement, then you believe that tightening the nut does nothing. Might as well just throw a 10mm hitch pin through there and call it good, right?
Tightening the nut places the bolt in tension, which creates clamping force across the bolted interface. This force creates friction between the parts, which is *really* what holds your parts together, and the tightening torque is a function of how much clamping force you can create before the bolt is stretched into plastic deformation.
If that bolt loosens up, or if the mating area between the surfaces isn't clean or even, then yes, the bolt is loaded in shear as well. It might continue to work for a while like that, but that's never the design intent.
If, as you say, the only force that upper link sees is from controlling axle wrap/braking torque, it should be easy then. Isn't the torque limited by either a) the friction of the tires on the ground or b) the weakest component in your drivetrain? From there it becomes a simple free-body diagram of torques and the reaction forces.
If the front tires are gripping with a coefficient of 0.9, say during braking, and you've got 2500 lbs over the front end, that's a reaction force of 2250 lbs at the tire contact patch. Figure a 35" tire with a 17" rolling radius and the net torque applied at the axle tube center is just over 3100 ft-lbs. If that single upper bolt is the only thing reacting that much torque, what's the loading on it become? Keeping in mind that the upper link isn't acting perpendicular to the reaction force, so the loading on that joint is increased even more to compensate.
(see above regarding transmitting force to bolts in shear loading)
In order to make your argument more clear - better define this 'impact' you're talking about. What direction is it coming from? What component on the truck is receiving that impact first? What's the real-life scenario you've got in mind?
Also, to put it in perspective, I've also broken a lower 9/16" bolt (approx. equivalent to your M14), which is still smaller than the 5/8" bolt I broke. And if it matters, that 5/8" bolt was in one of the rear uppers, not a front.
Just trying to explore reality here.
bert01xj
NAXJA Forum User
- Location
- souderton,pa
Who makes it the army core of engineers?:worship:
- Location
- Columbus, In
srmitchell
NAXJA Forum User
- Location
- Mckinleyville (Humboldt) CA
Does the techno jeep use IRO long arms?
That one sounded great.
That one sounded great.
- Location
- Reno, Nevada
I can guarantee you those bolts were not over-torqued.
(bold added above for emphasis)s14unimog said:
I value real world experiences over contradicting figures.
I am amazed that this is being debated as strongly as it appears. If you believe that a 10 mm bolt is strong enough for you, then buy the flippin kit and run it. Then real world experience will tell you if its strong enough or it isn't.
ktm racer 419
NAXJA Forum User
- Location
- ROW DIALIN
NASA! KTM can't break space bolts!
i go to my hardware store and buy fancy grade 8 9/16" and 5/8" bolts for a couple dollars each.
it's a single 10mm bolt which is less than the stock application with much larger tires and getting beaten on harder than a stock rig. it just isn't very strong and when it does go it breaks other things with it. If you are fine with that go fer it.
this:thumbup:
Ya know what fine. I give up, this is going no where. I don't work for IRO and have nothing to gain by defending their product. It seems this conversation is evolving into a more heated debate anyways. I appreciate the time you took to explain this to me. I've got the three link under my truck on 32's and have done mild off roading with it for a little more than 8 months now (I don't exactly live in Utah). As I continue to do wheeling trips I will observe it for myself under real world experiences. I originally spoke up in this thread to bring to light the problem I see with the loading capacity of the single upper bushing but that was over looked and I fell back into the topic that has kept this thread alive.
building a rig, wheelin a rig, and breaking a rig is what this hobby is all about. I'm sure I'll destroy many other components on my truck but this conversation has no end. Under the right circumstances any component will fail.
As many have requested, lets just let this thread die already.
btw, you have a badass XJ.
bert01xj
NAXJA Forum User
- Location
- souderton,pa
I just bought a jeep with the 8" iron rock kit it has 5/8 bolts on it. Do you think that will hold up ktm I don't wheel very hard as I don't have the cash to have another car as a dd and I can't have the jeep down for a long time.
Ktm you know I am just messing with you about breaking bolts right.
Ktm you know I am just messing with you about breaking bolts right.
