Iron Rock Rear Shock Mounts

differant shocks are differant thicknesses, depending on misalignment spacer widths. fox 2.0's are not the same as fox 2.5's, for example. have you acquired your shocks yet? fox makes some nice oem fitment shocks with conventional bushings.
 
Ideally you want the ends of the shock pivoting in the same direction at the same time. Slow movement like crawling may not make much of a difference, but once you start speeding up it's going to put a lit of stress on the bushings or heims, either one still has to abide by the laws of physics. Heims may allow for some additional movement and durability over bushings, but they're not meant to account for the shock moving in two directions at once.
 
differant shocks are differant thicknesses, depending on misalignment spacer widths. fox 2.0's are not the same as fox 2.5's, for example. have you acquired your shocks yet? fox makes some nice oem fitment shocks with conventional bushings.

No, I haven't bought shocks yet. My whole goal with this thread was to determine which upper and lower mounts I want to use so that I can in turn determine the shock length I need so that I can in turn purchase the right ones the first time. I'm leaning toward heims over bushings mostly because that's what the shocks I've been considering come with, but also because I just like the way the heims bolt up solidly.
 
Ideally you want the ends of the shock pivoting in the same direction at the same time. Slow movement like crawling may not make much of a difference, but once you start speeding up it's going to put a lit of stress on the bushings or heims, either one still has to abide by the laws of physics. Heims may allow for some additional movement and durability over bushings, but they're not meant to account for the shock moving in two directions at once.

I can see what you're saying. Using the IRO upper mount with a RuffStuff lower mount that maintains the factory mounting orientation will cause the ends to move in two different directions. Under compression/extension the lower heim will rotate on axis while the upper heim will move perpendicular to its axis.

So here's my question then... as a leaf sprung rear suspension compresses, the axle moves up and back. As it extends it moves down and forward. So isn't the axle moving in two different directions at once? Granted the fore and aft is a smaller movement than the up and down, but the axle is still moving in a second plane nonetheless. During this forward and back movement the upper heim will rotate on axis while the lower heim will move perpendicular to its axis, opposite of what occurs as a result of the up and down.

I thought this is what the whole debate over parallell vs. perpendicular ends on the front shocks was all about?:dunno:

(Oh and shhhhh..:shhh: my primary use for this rig isn't going to be go-fast, the go-fast guys just seem to be way better versed in all this shock mounting stuff so I started the thread here in JeepSpeed)
 
You're right, which is why when racers go through the floor with shocks, they are always mounted with the bolts perpendicular to the axle. Jeep's were'nt designed to go fast, and the stresses put on the shocks during normal driving and mild wheeling are negligible, which is why I mentioned speed. The axle is absolutely moving in two directions at once, but you should be fine mounting them in the factory orientation if you don't plan on hauling ass.
 
Heims may allow for some additional movement and durability over bushings, but they're not meant to account for the shock moving in two directions at once.

Wait. What?

That's how my rear is mounted:

4673499957_e21428a7ce_z.jpg


Granted it's a bit different application than being discussed here, but I don't see a problem with it...
 
I mean parallel up there in my first sentence as well. I'm not saying there is a big problem with it, I just don't think its ideal. Your mounting is the perfect example of the benefit of going with a heim over a bushing however.
 
I mean parallel up there in my first sentence as well. I'm not saying there is a big problem with it, I just don't think its ideal. Your mounting is the perfect example of the benefit of going with a heim over a bushing however.

I'm still a little confused. I did the front with both perpendicular, because the axle had more lateral movement because of the panhard, and the amount of travel isn't enough for the axle to move forward/back to the point where it binds the heim:

4255347933_cddea0a8eb_z.jpg


As long as you're not exceeding the movement of the heim, it could really care less how it's mounted. The ball is either is swiveling in the socket or rotating in the socket. Just gotta pick the best orientation for your geometry and packaging. I've even seen guys who have mounted shocks on top of the kingpin caps on steering knuckles before.

Bushings don't have the same freedom of movement, at least not if you want any kind of longevity from them...depending on lift height, I can see how the brackets the OP is asking about could put some pretty significant preload on the upper shock bushings.
 
Thanks for the discussion and advice regarding my questions guys. I'm feeling much more comfortable about proceeding with my plans for the rear shock set-up. I know it's in no way extreme like the race setups, but seeing the approaches that are taken for the hardcore stuff shows me that I should have no problems with my much milder configuration.

One more question... as vetteboy mentioned the heims are either swiveling in the socket or rotating in the socket. So long as they are not pushed past their design limits, does one type of motion cause them to wear out any quicker than the other?
 
In a bit late but for what its worth I have been using the IRO BPE for over three months and have no issues. Im running RE Mono's and every lined up perfect, I dont see how turning the shock 90* would mess up anything. HTH
 
In a bit late but for what its worth I have been using the IRO BPE for over three months and have no issues. Im running RE Mono's and every lined up perfect, I dont see how turning the shock 90* would mess up anything. HTH

Are you using them up front, or in back? And just to clarify, the RE Monotubes have bushings, not heims, correct?
 
Are you using them up front, or in back? And just to clarify, the RE Monotubes have bushings, not heims, correct?

Sorry it took me so long to reply.

Im using them front and rear. Yes the Mono's have bushings not heims.

I will take some pictures and post them up. I really like the design, simple and effective. Mine came Zinc coated not Powder Coated/Painted like in the pictures from IRO.
 
Just ordered these yesterday from Iron Rock Offroad, should be here in a couple of days. A little pricey once you factor in shipping, but I thought they were the cleanest looking design and that they appeared to cause the least amount of overall shock length loss when compared to the other options I explored.

IMG_9599.JPG


I spoke with one of the tech guys at IRO and told him I was planning on using them with heim jointed shocks and asked if he thought it would work. He said he saw no problem with it but that I'd have to figure out a way to adapt it to the correct sized bolt. The through bolts it comes with are 10mm. I asked about drilling it out to 1/2" and he said that he wouldn't recommend that as it wouldn't leave much metal on the bracket. He suggested maybe using 3/8" bolts as they are about the same size as 10mm.

So I'm pretty new to all this heim stuff. The I'm thinking I need a misalignment spacer that will reduce the through bolt on the heim from 1/2" to 10mm or 3/8". The 7100's parts list only shows a 1/2" to 12mm Heim Reducer Spacer. I looked at the ones on RuffStuff's site, but they all seem way too big for this application. What's a good source for smaller sized misalignment spacers? Also, I'm assuming I subtract the width of the heim from the width of the bracket and then divide by two to figure out the spacer width I need. Is this correct?

I'm going into this a little blind, but I guess I'll be the guinea pig here and see if I can't figure out a way to make this all work. I plan on using the IRO's for the upper mounts, the RuffStuff side mount shock brackets for the lower mounts, and Bilstein 7100's (or something comparable) for shocks.
 
any offroad shop worth a turd should have misalignment spacers available. kartek, ORW, etc. Dan @ RuffStuff also makes his own. You are correct you must run a misalignment spacer with heim jointed shocks, which will reduce the bolt size but allow the balls in the heim joint to pivot correctly.
 
FWIW, I run IRO bpe's still and I sheered a bolt off of the front, driver shock yesterday. I kept hearing this thumpin noise, turns outthat it was my shock flopping aroun and the hardware from the kit had failed
 
FWIW, I run IRO bpe's still and I sheered a bolt off of the front, driver shock yesterday. I kept hearing this thumpin noise, turns outthat it was my shock flopping aroun and the hardware from the kit had failed

Grade 8 hardware in my IRO kit. To be fair, that is about the best hardware you can stuff into a stock sized bushing sleeve.
I went with JK shocks and drilled the brackets to accept the larger hardware - will see how long that works... I'm already getting squeeks from the BPE against the axle housing. May throw a few tack welds on it next time I get my car to the shop...
 
Mine was grade 8 too, the problem was that it didn't come with washers, which in my case allowed the bolt to slowly get chewed down I suppose.

So the fix, two new grade 8 m10x1.5 bolts (60mm i think) and some washers:)
 
Mine was grade 8 too, the problem was that it didn't come with washers, which in my case allowed the bolt to slowly get chewed down I suppose.

So the fix, two new grade 8 m10x1.5 bolts (60mm i think) and some washers:)

Just make sure the shank is the right length such that the threads are not loaded. And also, no such thing as metric grade 8:). Rough equivalent is 12.9. Good luck.
 
bolt is the same thread pitch, shank is the same length, head is the same size (17mm) as the one that came from IRO... aaaannd I guess our parts store is wrong when they advertise their different hardwares.. grade 5, 8 both in metric and standard..??who knows...

But I do highly recommend anyone who runs this kit to grab some3/8's washers for the shock bolts, just to be safe:)
 
oh, and also FWIW, i was wrong about mine being grade 8, My IRO kit came with class 10.9 bolts, which I believe is only very very very marginally weaker than an 8... nonetheless... mine broke :D
 
Back
Top