Re longarms with passenger upper removed

[kastein]

I'm reasonably certain you are wrong here, for all but the most severe abuse (jeepspeed, etc.) That cast-in mount is pretty damn strong.

The reason most 3 link kits have you cut it off is so you can use a proper heim joint (or similar) instead of a pressed in bushing.

oh and you don't need to run a bridge to run a flex joint

:nono:

Yeah, I see what you're getting at but I have never seen a broken driver side mount, nor can I find any evidence of it ever happening on google. And I endo'd my jeep (hammered on the throttle going up a 3-4 foot ledge, rear axle ended up 4 feet in the air) without damaging the driver side upper mount at all, even though I folded the passenger side upper mount like tinfoil and ripped the driver side lower mount entirely off the axle housing.

 

[zachandandy]

Not sure a broken control arm in a severe crash or rollover means much to anybody. It's a unibody. Severe frontal impacts mean totaled vehicle. Who cares if the pinion is pointing forward at that point. Show me 1 case of a broken bolt in the uca that wasnt caused by severely damaging accident. 1 don't care if you have 30 extra bolts let alone 1, in a head on or rollover your jeep needs major repairs. As far as thinking I have a good idea, it's not mine, IRO sells the exact thing I'm refering to. If it's so unsafe, where are the failures? The lawsuits that would quickly put them out of business? Please don't flame me for looking at the work of real engineers and noticing that I can easily convert my current set up to theirs.

 

[rockclimber]

:nono:

Yeah, I see what you're getting at but I have never seen a broken driver side mount, nor can I find any evidence of it ever happening on google. And I endo'd my jeep (hammered on the throttle going up a 3-4 foot ledge, rear axle ended up 4 feet in the air) without damaging the driver side upper mount at all, even though I folded the passenger side upper mount like tinfoil and ripped the driver side lower mount entirely off the axle housing.

and if you didn't have your passenger mount connected you would have broken the driver side bolt or mount and ended up loosing your front driveshaft and possibly pinion.

Not sure a broken control arm in a severe crash or rollover means much to anybody. It's a unibody. Severe frontal impacts mean totaled vehicle. Who cares if the pinion is pointing forward at that point. Show me 1 case of a broken bolt in the uca that wasnt caused by severely damaging accident. 1 don't care if you have 30 extra bolts let alone 1, in a head on or rollover your jeep needs major repairs. As far as thinking I have a good idea, it's not mine, IRO sells the exact thing I'm refering to. If it's so unsafe, where are the failures? The lawsuits that would quickly put them out of business? Please don't flame me for looking at the work of real engineers and noticing that I can easily convert my current set up to theirs.

the problem with only running 1 upper with a 10mm bolt is that you have an extremely weak link on its own.

now if you called Currie and got them to build you an upper JJ bushing replacement with a 9/16 or better through bolt and installed that on the drivers side, then you drilled out your drivers side UCA to accept that bolt I'd be OK with it. because you are in a sense right, if a jeep is hurt bad enough to break the upper housing its probably totalled...but thats not a for sure thing. I've seen d-30's completely destroyed, everything else on the xj is fine... except the shocks and springs maybe

fyi, IRO's setup is stronger than RE's, and the problems with their setup have long been discussed.

and I'm flaming you because you asked for advice, then when you got all that advice you decided to ignore it simply because you didn't like the answer.

 

[kastein]

and if you didn't have your passenger mount connected you would have broken the driver side bolt or mount and ended up loosing your front driveshaft and possibly pinion.

I strongly doubt I would have broken the driver side mount. Like I said before, got any pics of it breaking? The passenger mount may as well have not been connected, it broke like it wasn't even there.

You are correct about the pinion though, it wrecked the U-joint and busted the retention tabs for the caps out of the yoke, and chewed a hole in the exhaust downpipe. I ended up throwing another d30 in because it was free and easier to beef up straight stock mounts than it was to build new ones from scratch.

 

[rockclimber]

I strongly doubt I would have broken the driver side mount. Like I said before, got any pics of it breaking? The passenger mount may as well have not been connected, it broke like it wasn't even there.

You are correct about the pinion though, it wrecked the U-joint and busted the retention tabs for the caps out of the yoke, and chewed a hole in the exhaust downpipe. I ended up throwing another d30 in because it was free and easier to beef up straight stock mounts than it was to build new ones from scratch.

I don't think you would have broken the mount... I think you would have broken the bolt, but it isn't out of the realm of possibility..

we all know the d30 housing is made out of paper mache.... it wouldn't take an unreasonable amount of force to break that mount off...

by having 2 bolts you most likely saved yourself an even bigger headache of a totally fubard driveshaft and possible t-case damage.:wave:

and I'm still looking for the pictures of the broken mount...but they do exist.

 

[zachandandy]

I was not ignoring your advice, I was debating its validity without throwing out meaningless insults. Real advice from real experience is great, but personal opinion from people who have no experience with a certain set up, especially when it's accompanied by insults, is of no use. You say its a safety issue, then sight freeway collisions and rollovers? You say the 10mm bolt will fail with no evidence of such. You say IROs system should fail, but i cant find 1 such report. Then you say there system is stronger than re's. Stronger how? So are you now saying it's not the 10mm bolt, but the link itself that is the problem? My entire point about radius arm binding is not that I need more travel, but smoother travel with less bind for free, who wouldn't want that?

 

[ktm racer 419]

My entire point about radius arm binding is not that I need more travel, but smoother travel with less bind for free, who wouldn't want that?

you wont notice anything

maybe some axle wrap/hop from there being half the rubber bushings there to hold the axle in place as there was before.

 

[rockclimber]

I was not ignoring your advice, I was debating its validity without throwing out meaningless insults. Real advice from real experience is great, but personal opinion from people who have no experience with a certain set up, especially when it's accompanied by insults, is of no use. You say its a safety issue, then sight freeway collisions and rollovers? You say the 10mm bolt will fail with no evidence of such. You say IROs system should fail, but i cant find 1 such report. Then you say there system is stronger than re's. Stronger how? So are you now saying it's not the 10mm bolt, but the link itself that is the problem? My entire point about radius arm binding is not that I need more travel, but smoother travel with less bind for free, who wouldn't want that?

sorry... I forgot this was a kids forum...:moon: sorry if I insulted you, but your idea is dangerous not only to you, but to everyone else on the road...

and besides... I'm having fun pissing everyone off:skull2:

the tensile strength of that 10mm bolt is 4900lbs; do the math and you will see how close to that number you come when having to slam the brakes at 65 mph

you want to know why you have not heard from people who have done this: because it is a bad idea; those people are probably dead.:hang:

smoother bind free travel:laugh2::roflmao:
thats funny right there.

 

[T to the B]

What if you used an axle truss with a NEW drivers side upper control arm mount like the below. Would that mount be sufficient? The mount also uses a much larger allen headed bolt. FWIW...I just spoke with IRO about their 3 link kit(as i'm interested in going this route later on), and they said for the multiple years they've been marketing the product they haven't had a single failure of the arms or differential mounts of any kind. Just adding this to the thread.

 

[zachandandy]

Tensile strength of a grade 10.9 10mm bolt is 56,000 psi( 1040MPaX145psi/MPaX3/8) and if you upgrade the factory bolt to a grade 12.9 your looking at 66,700 psi. And FYI a half inch grade 8 bolts tensile strength is only 75,000 psi. My point about your name calling was it's an example of your ignorance. It'll take much worse than calling me names to offend me, but your tensile strength was only off by 50000 psi so which one of us is truly the retard? By the way this tiny little week bolt in question doesn't break when it rips the passenger side mount off, but it is going to snap off driving down the road? I don't care what your opinion of IRO is, they have sold enough of these kits that there would be a lawsuit if your ignorant, paranoid, safety concerns were even remotely valid. Reading all the other threads regarding this type of setup is my I posted in the first place. Stupidity posses me of. "it can't work because I say so, it's unsafe unless the guys who built the kit built it that way?" Some actual research, real facts, that's what I was looking for.

 

[kastein]

who cares about tensile strength in this case? Are you guys actually thinking about what type of stress the bolt is under or just looking up and throwing numbers at each other?

It's a bolt in double shear. Check the shear strength.

Yes, shear and tensile strength are related, but this kind of sloppy thinking really annoys me especially when people try to prove their point using numbers and use the wrong ones.

 

[rockclimber]

Tensile strength of a grade 10.9 10mm bolt is 56,000 psi( 1040MPaX145psi/MPaX3/8) and if you upgrade the factory bolt to a grade 12.9 your looking at 66,700 psi. And FYI a half inch grade 8 bolts tensile strength is only 75,000 psi. My point about your name calling was it's an example of your ignorance. It'll take much worse than calling me names to offend me, but your tensile strength was only off by 50000 psi so which one of us is truly the retard? By the way this tiny little week bolt in question doesn't break when it rips the passenger side mount off, but it is going to snap off driving down the road? I don't care what your opinion of IRO is, they have sold enough of these kits that there would be a lawsuit if your ignorant, paranoid, safety concerns were even remotely valid. Reading all the other threads regarding this type of setup is my I posted in the first place. Stupidity posses me of. "it can't work because I say so, it's unsafe unless the guys who built the kit built it that way?" Some actual research, real facts, that's what I was looking for.

I meant 49000lbs.... typo.. which is much closer and the number I came up with after a quick search... its a little low, but not 50k.

even at 56000lbs still not enough IMO...

and who called names? I don't remember doing that.... whoever it is stop it.:shhh:

I also never said it would snap driving down the road, as a matter of fact I said it would be fine; I said when the SHTF it will break.

I have nothing against IRO...I don't like radius arm kits, but that has nothing to do with the people making them, it has everything to do with the fact that it is a bad suspension design.

I also never said that the bolt would break in the passenger side mount...we all know that mount is practically made of cardboard.

you're the one talking about changing a fundamental part of the suspension design; my safety concerns are no more ignorant than the notion that your suspension will somehow travel smoother by eliminating one upper link.:bs:

 

[zachandandy]

The binding of 1 radius arm moving up while the other is moving down should be obvious to anyone, the 2 triangles formed by the radius arms are trying to twist in opposite directions. Eliminate 1 triangle, eliminate the binding. Basic geometry. Yes the strength in question is shear load, but shear strength of bolts is less easy to come by and directly proportional to tensile strength. I used 3/8" for my calculations, but 10mm is actually .393 inches putting a grade 12.9 10 mm bolt only 5000psi weaker than the 1 bolt holding your leaf springs in. The system works, proven by IRO. There is no question about that.

 

[rockclimber]

there are 3 bolts holding the leaf springs... on each side...

and the same reason I used tensile strength is because I also couldn't not find a listing of shear strength.

 

[kastein]

there are 3 bolts holding the leaf springs... on each side...

and the same reason I used tensile strength is because I also couldn't not find a listing of shear strength.

3? looks like 2 to me.

No, the shackle bolt doesn't count here. That's like saying that a ten foot long rope is stronger than a 6 foot long rope when they are the same diameter.

 

[1990JEEPXJ]

now if you called Currie and got them to build you an upper JJ bushing replacement with a 9/16 or better through bolt and installed that on the drivers side, then you drilled out your drivers side UCA to accept that bolt I'd be OK with it.

so a bigger bolt somehow made the mount stronger? if im not mistaken they sell the exact part you describe.

fyi, IRO's setup is stronger than RE's

how so? it only uses the one cast mount on the diff which is apparently unsafe...


im not attacking you or anything, just trying to keep some consistency here. which seems to be lacking.

 

[rockclimber]

3? looks like 2 to me.

No, the shackle bolt doesn't count here. That's like saying that a ten foot long rope is stronger than a 6 foot long rope when they are the same diameter.

why don't both shackle bolts count? the both take the load of the axle.

 

[zachandandy]

If the 1 bolt at the front breaks on your leaf spring at speed it will be catastrophic.

 

[kastein]

why don't both shackle bolts count? the both take the load of the axle.

Think that one through a bit... the full load is placed on each bolt, rather than being shared between them. Alternatively, think of it this way, if either shackle bolt breaks, the shackle comes disconnected. A chain is only as strong as its weakest link, not as strong as all the links added up.

You're basically proving to me that I should take anything you say regarding engineering / suspension design with a pound of salt.

 

[rockclimber]

so a bigger bolt somehow made the mount stronger? if im not mistaken they sell the exact part you describe.

they do make a kit with a larger bolt size, its a recent development...and it doesn't make the mount stronger, but it does make the joint stronger

how so? it only uses the one cast mount on the diff which is apparently unsafe...

I meant the kit overall... the arms themselves are stronger because they are fixed and heavily gusseted.

im not attacking you or anything, just trying to keep some consistency here. which seems to be lacking.

I may be a bit confusing...im jumping around a bit... I don't think the cast diff mount is not strong; I just don't think it was designed to handle all the forces of the upper CA's on its own; Its still stronger than the 10mm bolt, but if you then upgraded to a 9/16"s currie kit I would start to be concerned about it... a simple bridge or truss welded to the tube on either side of the diff would beef it up plenty... in fact clayton makes a bridge designed to fit around it.