Midarm and rear outboard question

Superjay5

Superjay5

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Quick question regarding out boarding the rear shocks. I noted the midarm because the lack of a track bar.

I’m in the process of the rear shock outboard. I’ve have the upper poly towers set to the very back inside of frame. So the upper mounts are where they are gonna be.

Im set up with 12” foxes dialed in for 6” of up and 6” of down travel.

Im slightly rubbing the tire against the shock body at full articulation. I can still spin the tire by hand and I’ve read a little contact is okay.

But trying to get this dialed in perfectly, I’ve been moving the lower shock mount inboard more, but the more I look at it, I’m wondering if it would help if I move it more outboard.

There might be some geometry I’m not fully understanding here.

So my question is which direction should I be moving the lower mount to gain more clearance between tire and shock body.

I’m just looking to speed this up a bit, I’ve cycled the suspension so many times, tacked welded and cut tacks, rinse and repeat. You know the drill.

Thanks

@mrblaine @jjvw
 
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Isn’t the lower shock mount moving with the wheel since they are both on the axle, so that if you move it inboard more it will be farther from the tire at the axle, but the effect will be less toward the upper fixed shock mount. For me this is just a learning inquiry/thread. What’s your backspace? I don’t see how moving it outboard more would help, but I may not be fully understanding the axle movement either.
 
Superjay5 said:
Quick question regarding out boarding the rear shocks. I noted the midarm because the lack of a track bar.

I’m in the process of the rear shock outboard. I’ve have the upper poly towers set to the very back inside of frame. So the upper mounts are where they are gonna be.

Im set up with 12” foxes dialed in for 6” of up and 6” of down travel.

Im slightly rubbing the tire against the shock body at full articulation. I can still spin the tire by hand and I’ve read a little contact is okay.

But trying to get this dialed in perfectly, I’ve been moving the lower shock mount inboard more, but the more I look at it, I’m wondering if it would help if I move it more outboard.

There might be some geometry I’m not fully understanding here.

So my question is which direction should I be moving the lower mount to gain more clearance between tire and shock body.

I’m just looking to speed this up a bit, I’ve cycled the suspension so many times, tacked welded and cut tacks, rinse and repeat. You know the drill.

Thanks

@mrblaine @jjvw
Click to expand...

Inboard until it makes hard contact with the lower end of the mount at the frame. Also why I trim the mount down to about 1/4" below the frame.
 
mrblaine said:
Inboard until it makes hard contact with the lower end of the mount at the frame. Also why I trim the mount down to about 1/4" below the frame.
Click to expand...

Thanks mrblaine, appreciate it!

I have my upper mount trimmed about the same 1/4” below. I still have a good 1/2” of clearance there at full articulation, so more inboard I will go.

I felt like I was on the right track, but since this is my first attempt at this, I’ve been making very small adjustments.
 
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JMT said:
Isn’t the lower shock mount moving with the wheel since they are both on the axle, so that if you move it inboard more it will be farther from the tire at the axle, but the effect will be less toward the upper fixed shock mount. For me this is just a learning inquiry/thread. What’s your backspace? I don’t see how moving it outboard more would help, but I may not be fully understanding the axle movement either.
Click to expand...

I’m 90% sure my backspacing is 3.5” which I assumed I would have a lot of clearance with that offset, but I don’t.

I was pretty sure moving it inboard made the most sense, but since this is my first go at this I was making very minor adjustments and wasn’t seeing the clearance I wanted, so I started questioning if there was some geometry going on that I didn’t understand.

Confirmed by mrblaine that inboard is the way to go.

There is not a little wiggle room with this mod, I’ve cycled the suspension so many times after making adjustments, I just wanted to confirm so I could maybe save myself some time moving the lower mount around.
 
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Superjay5 said:
I’ve cycled the suspension so many times, tacked welded and cut tacks, rinse and repeat. You know the drill.
Click to expand...

I remember completing my outboard and yes, this is pretty much the process 😅 Tack, cycle, cut, tack, cycle, cut. Sounds like you have your answer, but the uppers are already welded into place?
 
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tworley said:
I remember completing my outboard and yes, this is pretty much the process 😅 Tack, cycle, cut, tack, cycle, cut. Sounds like you have your answer, but the uppers are already welded into place?
Click to expand...

Yes, the uppers are fully welded now, that was after a ton of adjusting. I have them fully back to the inside of the frame.

My tires would still spin at full articulation, there was just slight rubbing, which I’ll move the lower inboard a little more to correct. I’ve moved the lowers a dozen times or so it seems to get to this point and just wanted to confirm I wasn’t missing something.

It’s taken so much cycling to get here, but being my first time I always made tiny adjustments.
 
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Superjay5 said:
I’m 90% sure my backspacing is 3.5” which I assumed I would have a lot of clearance with that offset, but I don’t.

I was pretty sure moving it inboard made the most sense, but since this is my first go at this I was making very minor adjustments and wasn’t seeing the clearance I wanted, so I started questioning if there was some geometry going on that I didn’t understand.

Confirmed by mrblaine that inboard is the way to go.

There is not a little wiggle room with this mod, I’ve cycled the suspension so many times after making adjustments, I just wanted to confirm so I could maybe save myself some time moving the lower mount around.
Click to expand...

This is all very helpful to me, so thank you.
 
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My only contribution to this is that the primary endeavor of building shock mounts is one of finding the boundaries and limits of the shock travels and movements relative to everything else in the vicinity. From there you have to put things in the best or least compromised position.
 
Last edited:
mrblaine said:
Inboard until it makes hard contact with the lower end of the mount at the frame. Also why I trim the mount down to about 1/4" below the frame.
Click to expand...

What was the original purpose of having the mounts slightly angled before? Was it to allow the shock body to move inboard more since the upper mount was more outboard? Did it not make enough difference therefore just going flush to backside of the frame for ease of installation?
 
hosejockey61 said:
What was the original purpose of having the mounts slightly angled before? Was it to allow the shock body to move inboard more since the upper mount was more outboard? Did it not make enough difference therefore just going flush to backside of the frame for ease of installation?
Click to expand...

It is all the same purpose. Put the shock where the tire doesn't rub on it very hard and where it doesn't hit the frame going the other way.
 
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hosejockey61 said:
What was the original purpose of having the mounts slightly angled before? Was it to allow the shock body to move inboard more since the upper mount was more outboard? Did it not make enough difference therefore just going flush to backside of the frame for ease of installation?
Click to expand...

To clarify some, if you look at the shocks head on from the rear of the rig, they should angle outward at the axle or at worst, straight up and down and not out at the top. I can not prove that there is a performance difference since there really shouldn't be, but that type of install looks silly to me. If it doesn't bother you, go for it.
 
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I’ll add my 2 cents here, even tho’ I’ve copied mrblaine as close as I can. I bet I have pictures saved of his handy work going back close to 10 years.

@hosejockey61 i also watched your video on this a handful of times, which was very helpful.

As I stated before, since this was my first time I made a lot of small adjustments to get to this point.

Upper mount, when I first cut my frame I left about 1/4” top and bottom of frame intact. I had bad tire/shock clearance issues, so I kept slowly taking more of the frame away.

After so many tries I was to the point that my cut at the bottom of the frame was flush to the back of frame, then I may have had about an 1/8” at the top, which if I remember right put the upper mount tipped out 4.6 degrees. Still was having pretty bad tire/shock clearance. I should note lower mount was shoved tight to the lower control arm mount with the the rolled over edge of the control arm mount removed.

It wasn’t until I cut the upper part of the frame tight to the back wall that I finally gained clearance to allow the tire to spin at full articulation. Removing 1/8” or 4.6 degree tilt made a huge difference!

So I could leave it as is, as the tire will spin, but I have so much time invested in this, if I could at least have a 1/4” of clearance I would prefer that.

My lower shock mount will need to be moved in, at this point it’s tight against the lower control arm mount. So I will need to cut that section of LCM off and have the lower shock mount be in plane with it.

This will leave my shock slightly angled out more on the axle side, which I agree with Blaine it would look stupid having it narrower on the axle side.

 
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Superjay5 said:
I’ll add my 2 cents here, even tho’ I’ve copied mrblaine as close as I can. I bet I have pictures saved of his handy work going back close to 10 years.

@hosejockey61 i also watched your video on this a handful of times, which was very helpful.

As I stated before, since this was my first time I made a lot of small adjustments to get to this point.

Upper mount, when I first cut my frame I left about 1/4” top and bottom of frame intact. I had bad tire/shock clearance issues, so I kept slowly taking more of the frame away.

After so many tries I was to the point that my cut at the bottom of the frame was flush to the back of frame, then I may have had about an 1/8” at the top, which if I remember right put the upper mount tipped out 4.6 degrees. Still was having pretty bad tire/shock clearance. I should note lower mount was shoved tight to the lower control arm mount with the the rolled over edge of the control arm mount removed.

It wasn’t until I cut the upper part of the frame tight to the back wall that I finally gained clearance to allow the tire to spin at full articulation. Removing 1/8” or 4.6 degree tilt made a huge difference!

So I could leave it as is, as the tire will spin, but I have so much time invested in this, if I could at least have a 1/4” of clearance I would prefer that.

My lower shock mount will need to be moved in, at this point it’s tight against the lower control arm mount. So I will need to cut that section of LCM off and have the lower shock mount be in plane with it.

This will leave my shock slightly angled out more on the axle side, which I agree with Blaine it would look stupid having it narrower on the axle side.
Click to expand...

The other thing that affects this is how close to the center of the tire the shock body is. If you set the shock on top of the axle tube straight up viewed from the side, the clearances would be impossibly tight. As you move the shock back from that, the clearances get better but as you do so, the extreme amount affects the shock's ability to do its job. Roughly 90 degrees to the lower control arm is a reasonable starting point and that moves the shock into a more favorable location with more room to work.

Folks cheat that more than a bit by leaning the shock back further to get longer shocks on. That causes more issues than it solves.
 
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I have mine set perfectly at 90degree at ride height.

One more reason to not like metal cloak. I used there rear upper coil mounts as mine were rusted so bad even though my frame is fairly clean.

I had clearance issues with the metal cloak mounts, they too would rub the tire at full articulation. This picture doesn’t show it but I had to take the grinder to them and remove as much material as I could from the lower edge of the mount. It clears now, but I had to remove quite a bit.

Not sure if the stock mounts would also rub, but since I’ve never seen this issue brought up I assume they don’t.

B4E72400-493D-4360-9A4E-F394E595D0C5.jpeg
 
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Superjay5 said:
I have mine set perfectly at 90degree at ride height.

One more reason to not like metal cloak. I used there rear upper coil mounts as mine were rusted so bad even though my frame is fairly clean.

I had clearance issues with the metal cloak mounts, they too would rub the tire at full articulation. This picture doesn’t show it but I had to take the grinder to them and remove as much material as I could from the lower edge of the mount. It clears now, but I had to remove quite a bit.

Not sure if the stock mounts would also rub, but since I’ve never seen this issue brought up I assume they don’t.

View attachment 478070
Click to expand...

You have your upper Currie bumpstop cups upside down. Fix that. They don't have to be a perfect 90. Close is good enough. We don't have stock spring perch issues.
 
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mrblaine said:
The other thing that affects this is how close to the center of the tire the shock body is. If you set the shock on top of the axle tube straight up viewed from the side, the clearances would be impossibly tight. As you move the shock back from that, the clearances get better but as you do so, the extreme amount affects the shock's ability to do its job. Roughly 90 degrees to the lower control arm is a reasonable starting point and that moves the shock into a more favorable location with more room to work.

Folks cheat that more than a bit by leaning the shock back further to get longer shocks on. That causes more issues than it solves.
Click to expand...

This really clarified a long standing question I have had. Thanks for explaining very clearly.
 
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psrivats said:
This really clarified a long standing question I have had. Thanks for explaining very clearly.
Click to expand...

This also becomes a bigger issue when going to coilovers. Spring and shock rates decline as more angle is added. This was a major issue with the Warn XCL kit and a consequence of packaging. Here are the correction numbers that QA1 uses for baseline setup.

SHOCK ANGLE CORRECTION FACTOR
10 0.96
15 0.93
20 0.88
25 0.82
30 0.75
35 0.66
40 0.59
45 0.50
 
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Blackjack said:
This also becomes a bigger issue when going to coilovers. Spring and shock rates decline as more angle is added. This was a major issue with the Warn XCL kit and a consequence of packaging. Here are the correction numbers that QA1 uses for baseline setup.

SHOCK ANGLE CORRECTION FACTOR
10 0.96
15 0.93
20 0.88
25 0.82
30 0.75
35 0.66
40 0.59
45 0.50
Click to expand...

Never even knew that Warn made suspension kits in the past. Is this the one you are talking about here? I think I was 17-18 and lived in a different country when this came out 😂

https://www.rockcrawler.com/features/newsshorts/04october/blackdiamond_xcl.asp
 
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