Need help designing cage/back half of my chassis.

Van-go

Van-go

Not an old man
Joined
Dec 11, 2014
Location
Greensboro
Hopefully gonna have this thing all tacked together in the next week. I need some help designing the rest of the tube work/back half.
I want to be able to do trailing arms in the future but for now will likely run a 16in shock in the rear.
It will have skins from a YJ on it. (Cowl back to right behind door jamb.
May do a 4 seater, but likely just a 2 seater.
Here’s what I’ve got.
E2250C51-7705-4AC9-83C2-062E8B3D2965.jpeg

Finished product is supposed to look like this, but I’m going for more of a buggy look and not a full body Jeep.
504018C6-D44A-470B-AC9A-DD7F124D3820.jpeg
 
Van-go said:
Hopefully gonna have this thing all tacked together in the next week. I need some help designing the rest of the tube work/back half.
I want to be able to do trailing arms in the future but for now will likely run a 16in shock in the rear.
Click to expand...

Why couldn't you do a trailing arm with a single 16" shock ?

Also, for a trailing arm build, you need your shock package mocked up first then build tubing around it.

Otherwise it's a recipe for disaster.
 
Bebop said:
Why couldn't you do a trailing arm with a single 16" shock ?

Also, for a trailing arm build, you need your shock package mocked up first then build tubing around it.

Otherwise it's a recipe for disaster.
Click to expand...
Good advice. I have a set of 14in ORI’s and a set of 16’s.
I was thinking of running 14’s in the trailing arms, then fitting 16’s up front.
A 40in trailing arm should net about a 115in wheelbase which is about where I want to be. I kinda want to push it out to 118/120. But not sure how long is too long for trailing arms.
 
46" arms is the standard for short setups.

That's what I have on mine. BKORs are similar. IMO they are long and drag a bit, but that's part of it. Shorter would probably help, but be detrimental for angles and geometry in my case.

My buggy is 117" WB, WODs are ususally 115". BKORs are 125"

Pick what you like and roll with it.

14" on arms and 16" up front will absolutely work good and will net enough travel to really mob around in comfort. If you can get those ORIs tuned right.
 
Bebop said:
46" arms is the standard for short setups.

That's what I have on mine. BKORs are similar. IMO they are long and drag a bit, but that's part of it. Shorter would probably help, but be detrimental for angles and geometry in my case.

My buggy is 117" WB, WODs are ususally 115". BKORs are 125"

Pick what you like and roll with it.

14" on arms and 16" up front will absolutely work good and will net enough travel to really mob around in comfort. If you can get those ORIs tuned right.
Click to expand...
Yeah I do eventually want to go to quality coil overs, bumps, etc. heck maybe even some bypasses down the road.
The ORI’s were cheap enough for me to give them a shot. If I hate them, I’ll make some $ selling them and upgrade to a tuned coil over.
 
Van-go said:
Yeah I do eventually want to go to quality coil overs, bumps, etc. heck maybe even some bypasses down the road.
The ORI’s were cheap enough for me to give them a shot. If I hate them, I’ll make some $ selling them and upgrade to a tuned coil over.
Click to expand...

Be carefull that ORIs and coilovers/bypasses have different compressed/extended length. Will require a mount rework for sure.

easy(ish) to do on a axle mounted shock setup, harder on a trailing arm since it forces you to rework the upper mount on the chassis.
 
Bebop said:
Be carefull that ORIs and coilovers/bypasses have different compressed/extended length. Will require a mount rework for sure.

easy(ish) to do on a axle mounted shock setup, harder on a trailing arm since it forces you to rework the upper mount on the chassis.
Click to expand...
Good info. I wonder how far off they are. I’ll do some research.
 
@Bebop
14in ORI is 21.825in comp & 35.2in ext.
14in radflo is 24.49in comp & 38.5in ext.

So I basically need to make my mount off of a tube to drop an extra 3in for ORI’s if I ever want to switch to a coil over. Any other recommendations to make the swap at a later date?
 
By your data the ORIs move about 13.4"
Think about where the axle will end up at full bump/ride height. If you want to keep a true 50/50 on the shock you'll need to move the upper mount more than 3". If you want to make your life easy you define a full bump location and will match the location with the new shock mounts. Just more room for error

Make sure that the driveline will accept the angle of your projected droop and bump numbers (with the coilovers). I have 24" of strapped travel in mine and the pinion angle change is very important to keep the u-joints happy since you can quickly get crazy angles with such big travel numbers.

Ooooooor, you could sell the ORIs and go to coilovers from the get go and not have to deal with all this BS. And you can probably break even pretty easily given how hot ORIs are right now.
 
Bebop said:
By your data the ORIs move about 13.4"
Think about where the axle will end up at full bump/ride height. If you want to keep a true 50/50 on the shock you'll need to move the upper mount more than 3". If you want to make your life easy you define a full bump location and will match the location with the new shock mounts. Just more room for error

Make sure that the driveline will accept the angle of your projected droop and bump numbers (with the coilovers). I have 24" of strapped travel in mine and the pinion angle change is very important to keep the u-joints happy since you can quickly get crazy angles with such big travel numbers.

Ooooooor, you could sell the ORIs and go to coilovers from the get go and not have to deal with all this BS. And you can probably break even pretty easily given how hot ORIs are right now.
Click to expand...
Know anyone that wants some ORI’s? lol
I feel like I should listen to you…
The 14inch ones are brand new in box and the 16’s were lightly used before they were swapped out for coil overs.

I was thinking of going with radflo 2.5in 14in for the rear. Any other recommendations for size/length/brand?
 
Fox Factory is at the top of the list in terms of quality and parts used. But spares are hard to come by these days.
Radflos are great alternatives, are very similar and the parts are easier to come by.
Kings are good shocks too, they just are more expensive than the other 2 options if you want them with similar specs.
Everyone is a ways out these days. Depending on timeline you may have to go with whatever is in stock.

No matter what get reservoirs.

ORIs are pretty easy to sell, I've seen some on market place for what I thought was crazy pricing and they were gone quick.

Final blow :

Coilovers and bypasses share the same length. So if you buy some 14s for the rear and 16s for the front, you can totally use the 16s in the rear next to the 14s as a way to build your shock mounts for the bypasses before even having to buy them. No sure if I'm clear but that's a significant time saver in the long run.
 
Accutune is supposed to get another shipment of Fox coilovers sometime late July. When I talked to them a few weeks ago, not all of the shipment was sold out but that could have changed.

I agree with @Bebop, sell the ORI's and go to coilovers now if you plan to in the future.
 
Bebop said:
Fox Factory is at the top of the list in terms of quality and parts used. But spares are hard to come by these days.
Radflos are great alternatives, are very similar and the parts are easier to come by.
Kings are good shocks too, they just are more expensive than the other 2 options if you want them with similar specs.
Everyone is a ways out these days. Depending on timeline you may have to go with whatever is in stock.

No matter what get reservoirs.

ORIs are pretty easy to sell, I've seen some on market place for what I thought was crazy pricing and they were gone quick.

Final blow :

Coilovers and bypasses share the same length. So if you buy some 14s for the rear and 16s for the front, you can totally use the 16s in the rear next to the 14s as a way to build your shock mounts for the bypasses before even having to buy them. No sure if I'm clear but that's a significant time saver in the long run.
Click to expand...
ORI’s sold without even posting them up.
now I’m trying to figure out the process of getting coil overs and what trailing arms I want. Any recommendations?
I like the idea of Busted Knuckles arms. They don’t drop below the centerline and use a bushing/uniball on one end to keep from rolling.
How do I know (or guess) what springs etc I need before the rig is built?
Do I just order the shock part and build it around them at full bump? I know I need corner weights etc to order coil overs and get close, but I can’t get the weight until I build the thing.
First time doing all of this so excuse my ignorance.
 
bustedknuckleoffroad.com

BKOR Ultimate Trailing Arms

PLEASE, NOTE THE ORIGINAL YOUTUBE VIDEO SHOWS 1.75" HEIMS. THESE HAVE BEEN DISCONTINUED. This kit includes and 1.50" heims, and these have plenty of BEEF. These are the ULTIMATE Trailing arms. The MASSIVE D.O.M. housing houses a 1.25" uniball with spacers to allow a 1" bolt. Each side of the...
bustedknuckleoffroad.com bustedknuckleoffroad.com
 
Van-go said:
ORI’s sold without even posting them up.
now I’m trying to figure out the process of getting coil overs and what trailing arms I want. Any recommendations?
I like the idea of Busted Knuckles arms. They don’t drop below the centerline and use a bushing/uniball on one end to keep from rolling.
How do I know (or guess) what springs etc I need before the rig is built?
Do I just order the shock part and build it around them at full bump? I know I need corner weights etc to order coil overs and get close, but I can’t get the weight until I build the thing.
First time doing all of this so excuse my ignorance.
Click to expand...

No need to excuse yourself, we all start somewhere and nobody is born with innate knowledge about this shit.

You buy the shocks without the springs. You build the whole thing at various heights depending on what you are doing.

You set up ride height with the shocks half way through their travel
You set up bumpstops and check clearances at full bump
You setup lines and driveshafts at full droop

Depending on what else you need to do, you'll make it happen at full bump or ride height. I set caster at ride height and will build the rest of the vehicle (non relevant to suspension) at full bump because it makes it easier to climb in and out when it's lower.

Springs get ordered when the vehicle is done and driving.




BKOR trailing arms are great. If you are really rough on shit like me you may bend them so they would benefit from a full length truss, like I did. Check my buggy build thread for more details.
Major thing I can tell you is to pay attention to properly spacing the shock mounts when you're welding them. they have a tendancy to close up during welding and it makes it a giant pain to install the shocks. And you'll have to install/remove them a few times during the tuning process so you better take your time and do it right. Better be too wide than not enough.

There are other trailing arm options out there but if you want a one stop shop product, I'd say the BKOR ones are hard to beat. Def not free though. If you have access to a lathe you can build yours cheaper. The main thing to remember is that they need to be strong as they experience a shit ton of load.
 
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Bebop said:
No need to excuse yourself, we all start somewhere and nobody is born with innate knowledge about this shit.

You buy the shocks without the springs. You build the whole thing at various heights depending on what you are doing.

You set up ride height with the shocks half way through their travel
You set up bumpstops and check clearances at full bump
You setup lines and driveshafts at full droop

Depending on what else you need to do, you'll make it happen at full bump or ride height. I set caster at ride height and will build the rest of the vehicle (non relevant to suspension) at full bump because it makes it easier to climb in and out when it's lower.

Springs get ordered when the vehicle is done and driving.




BKOR trailing arms are great. If you are really rough on shit like me you may bend them so they would benefit from a full length truss, like I did. Check my buggy build thread for more details.
Major thing I can tell you is to pay attention to properly spacing the shock mounts when you're welding them. they have a tendancy to close up during welding and it makes it a giant pain to install the shocks. And you'll have to install/remove them a few times during the tuning process so you better take your time and do it right. Better be too wide than not enough.

There are other trailing arm options out there but if you want a one stop shop product, I'd say the BKOR ones are hard to beat. Def not free though. If you have access to a lathe you can build yours cheaper. The main thing to remember is that they need to be strong as they experience a shit ton of load.
Click to expand...
Thanks a bunch for the advice. And yeah trailing arms (especially at the axle mount) take a heck of a load.
 
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