“Sim shock” for cycling suspension for outboard

rjaym · Jun 29, 2026

Mentally prepping for out boarding the rear of my LJ. I keep thinking about the countless suspension cycling to get things right. Tire off/on measure/test etc. and got to wonderin’ if the folks that do this more than once in a lifetime use a dead shock or something similar to confirm clearances.
I did watch the BFH video and they put together a couple representations of a shock at full and compressed length. But that didn’t allow consideration for the shock body. Just thinking about Fighting a “live shock” in mock up makes me sore and irritated.
So I’m asking, is there a clever method to doing this? My first thought was something like what BFH did but with round tubing on 1 end - or fashion something that is adjustable/sliding like a shock. Any input appreciated.

macleanflood · Jun 29, 2026

You're overcomplicating it just like I did.

Buy a couple of rod ends, some square tube and make a couple of mock ups.

Also... there's a lot to be said about all the measuring and right angles and getting the tower in just the right spot...but in the end there's really a narrow spot it'll actually fit in. Everything else is more or less a compromise.

Also check @mrblaine 's post in the resources section. I think it's on the last page. That's really the definitive source of information. Everything else is second hand.

Here's my outboard experience.

View: https://youtu.be/qg4WkLsq_hU?is=ZSPZPvEqmEphq9Ti

-Mac

rasband · Jun 29, 2026

The reality is that you're probably going to lightly rub the shock body. There is only so much room to negotiate the tower in all four directions and the dynamic forces wheeling look slightly different than what we can reproduce cycling suspension on stock axles and common backspacing.

This is one of said outboards in the BFH catalogue. I don't remember when we did it, but it's been through a decent number of trails since then (I think a few moab trips, sand hollow, and most of the CO trails) and only has some surface rash that so far seems to not matter. I suspect it may not matter in any reasonable timeline.

We should ask @mrblaine though, he's done countless outboards and could tell us based off his significant sample size and him caring enough to improve everywhere he can.

mrblaine · Jun 29, 2026

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macleanflood said:
You're overcomplicating it just like I did.

Buy a couple of rod ends, some square tube and make a couple of mock ups.

Also... there's a lot to be said about all the measuring and right angles and getting the tower in just the right spot...but in the end there's really a narrow spot it'll actually fit in. Everything else is more or less a compromise.

Also check @mrblaine 's post in the resources section. I think it's on the last page. That's really the definitive source of information. Everything else is second hand.

Here's my outboard experience.

View: %5BURL%5Dhttps://youtu.be/qg4WkLsq_hU?is=ZSPZPvEqmEphq9Ti[/URL]

View attachment 697138 View attachment 697139

-Mac

The rod ends tube only works well for the fronts. For the rears if you use the Poly towers, you need 1 stick set up with cross tubes that fit in the mounts nicely that a 1/2" bolt fits through easily. If you don't do it that way, you can easily wind up with the lower out of whack far enough that the shock eye binds on the mount. Plus, it squares up the tower and allows you to perfectly center the shock fore and aft at ride height.

My most import mock up stick is ride height. The rest can easily be done with the shocks with the nitrogen charge depleted. If you start with the rig and axle at ride height, do your rough in of the tower, the only thing you are doing with the other two, full compression and extension is just checking clearances so you know if you need to move the lower around on the axle.

No matter what else is important, plan on cutting upper all the way into the frame and adjust everything else with the lower.

rasband · Jun 29, 2026

mrblaine said:
My most import mock up stick is ride height. The rest can easily be done with the shocks with the nitrogen charge depleted.

I don't remember Mike's full video, but this was definitely a key part I forgot about. Ride height mock ups with my old heims and we discharged the shocks for the tack and check part of the flexing process - @jjvw has a nitrogen tank that we could re-charge the shocks with. He's been kind enough to let me use it a few times now.

jjvw · Jun 29, 2026

rasband said:
I don't remember Mike's full video, but this was definitely a key part I forgot about. Ride height mock ups with my old heims and we discharged the shocks for the tack and check part of the flexing process - @jjvw has a nitrogen tank that we could re-charge the shocks with. He's been kind enough to let me use it a few times now.

Our next rear outboard needs to not use rod ends. Blaine's method of bolts directly though the square tube is the easiest way to do it and does most of the positioning work automatically.

rasband · Jun 29, 2026

jjvw said:
Our next rear outboard needs to not use rod ends. Blaine's method of bolts directly though the square tube is the easiest way to do it and does most of the positioning work automatically.

Is that because it removes the movement of the rod ends and encourages things to be largely square?

jjvw · Jun 29, 2026

rasband said:
Is that because it removes the movement of the rod ends and encourages things to be largely square?

Correct. The upper and lower mounting bolts are parallel to each other. Adding rod ends to the sticks does nothing to help locate and place anything. We knew this last time. But it didn't happen.

Edit-Not 90°

mrblaine · Jun 29, 2026

jjvw said:
Correct. The upper and lower mounts are at 90° to each other. Adding rod ends to the sticks does nothing to help locate and place anything. We knew this last time. But it didn't happen.

Yep, so no matter where you put the upper, the lower is square to it and the shock body is centered in the mount fore and aft. That comes from me taking apart other folk's outboard jobs where I had to put the lower eye in first and then flex the shaft to get the upper in at full droop. No good at all and the easy way to stop that is with mock up sticks that have squarely mounted end tubes.

mrblaine · Jun 29, 2026

jjvw said:
The upper and lower mounts are at 90° to each other.

Forgive my lack of geometrical excellence, but wouldn't the upper and lower be 0 degrees to each other??

jjvw · Jun 29, 2026

mrblaine said:
Forgive my lack of geometrical excellence, but wouldn't the upper and lower be 0 degrees to each other??

Correct! I forgot that the lower bolt is perpendicular to the axle when using Poly mounts

Abendage · Jun 29, 2026

jjvw said:
Our next rear outboard needs to not use rod ends. Blaine's method of bolts directly though the square tube is the easiest way to do it and does most of the positioning work automatically.

Damn I wish I would have thought of that.

I came in to drop the tip that if you have a SwayLoc to not buy heims for mockup as they take a 1/2” bolt and the studs are 1/2-20, so I just welded some nuts in my mock up square tubing and borrowed the SwayLoc rod ends for mock up. I spent way too much time making sure the rod ends were square in the mounts though and fixed ends would have been much easier.

rjaym · Jun 30, 2026

Appreciate the tips. I purchased the poly perf mounts ( 10% off sale ) I’ll start gathering material for the “shock sticks” . I don’t have a rear TB to be concerned about and I’ve already “ flipped “ the P brake when I installed the mid arm.

rasband · Jun 30, 2026

Abendage said:
I came in to drop the tip that if you have a SwayLoc to not buy heims for mockup as they take a 1/2” bolt and the studs are 1/2-20, so I just welded some nuts in my mock up square tubing and borrowed the SwayLoc rod ends for mock up

We did this same thing with mine, but using my old rod ends that I replaced before doing the midarm - they may still be in the BFH garage. More new tricks for if/when Adam decides to outboard!

mrblaine · Jun 30, 2026

rjaym said:
Appreciate the tips. I purchased the poly perf mounts ( 10% off sale ) I’ll start gathering material for the “shock sticks” . I don’t have a rear TB to be concerned about and I’ve already “ flipped “ the P brake when I installed the mid arm.

Not explained well enough so far but a big benefit of the ride height stick is it also sets the height of the tower. You can prop the lower mount on a small floor jack up against the axle tube with the stick and upper tower attached. Land the tower against the frame, clamp it, and then you can mark where the lower goes, clean, prep, and then tack the lower in place as a start. Put the stick back in and now you have a solid support for the tower. Push it against the frame, mark down both sides to get the angle. Cut slightly inside those marks, take that all the way back to the inside face of the frame tube.

Clean up the cuts, shove the tower up from the bottom and clamp it in place off to the side, check it with the stick. If the bolt won't go in, widen the cuts until it does.

Pro-tip #1- One side face of the tower almost always winds up square to the frame tube.
Pro-tip #2- The rear side of the tower almost always winds up within 1/8" or so of the upper edge of the oblong hole in top of the frame.
Pro-tip #3- If you don't have a universal square, get one or something equivalent.

https://www.ebay.com/itm/1983179928...pid=5337789113&customid=&toolid=10001&mkevt=1

rjaym · Jun 30, 2026

Thanks for that valuable information. - and yes I have a unisquare.

rjaym · Jul 2, 2026

Length of ride height stick? …Because I haven’t purchased the shocks, but know I’m going with 12” travel and very likely fox brand - I’m making the ride height stick 25” long ( eye to eye). (Collapsed length + 6” ) average of a fox 12” shock. Again I’m imagining folks that do this more than once in a lifetime have a standard “stick” for a given shock.
I haven’t cut anything besides the broken oe mount. I’ve got the bracket in the vicinity of its home ( whatta PITA juggling the bracket /clamp / and snug up clamp solo!) But once I’m confident about the stick length ( asking here) I”ll get the lower tacked

jjvw · Jul 2, 2026

rjaym said:
Length of ride height stick? …Because I haven’t purchased the shocks, but know I’m going with 12” travel and very likely fox brand - I’m making the ride height stick 24.75” long ( eye to eye). (Collapsed length + 6” ) average of a fox 12” shock. Again I’m imagining folks that do this more than once in a lifetime have a standard “stick” for a given shock.
I haven’t cut anything besides the broken oe mount. I’ve got the bracket in the vicinity of its home ( whatta PITA juggling the bracket /clamp / and snug up clamp solo!) But once I’m confident about the stick length ( asking here) I”ll get the lower tacked
View attachment 697570

View attachment 697571

View attachment 697572

View attachment 697573

Assuming centers of eyes...
(((Extended length-compressed length)/2)+Compressed length)=Shock length at normal ride height

Alternatively...
(Extended length-((Extended length-Compressed length)/2)=Shock length at normal ride height

sab · Jul 2, 2026

jjvw said:
Assuming centers of eyes...
(((Extended length-compressed length)/2)+Compressed length)=Shock length at normal ride height

Alternatively...
(Extended length-((Extended length-Compressed length)/2)=Shock length at normal ride height

Or, even easier, it’s halfway between extended and compressed, which is the average:

extended length + compressed length
_________________________________________
2

rasband · Jul 2, 2026

sab said:
Or, even easier, it’s halfway between extended and compressed, which is the average:

extended length + compressed length
_________________________________________
2

I like simplified equations.

“Sim shock” for cycling suspension for outboard

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