4-Link Geometry Data thread

DesertGoat

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Joined
Apr 4, 2022
Messages
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Location
San Diego
I'm currently wrestling with decision making on my truck - wondering if my link spacing on my frame is too narrow. It looks fine to me and a few dudes but a few others are suggesting that it looks wrong.

Something that I think would help me & a lot of other folks may be to crowd-source a set of data from other trucks' geometries. This would just be used to gut-check a new build's numbers - to check if what we're going to build is close to what other people have been doing successfully.

If you want to help out, the community would love it, I'm sure.
Totally understand if you want to keep the secret race sauce private, though.
Feel free to fIll out as much of this as you want to share.
Here's a generic list of things that I think might be helpful:

Truck purpose: (Race, prerunner, rock crawler, other)
Approximate Wheelbase = <>
Approximate Track width = <>
Tire size = <>
Trailing arm length = <>
Upper link length = <>

Frame side Link Info
upper link width/spread = <>
Lower link width/spread = <>
Vertical upper-to-lower link spread = <>

Axle side info
upper link width/spread = <>
Lower link width/spread = <>
Vertical upper-to-lower link spread = <>
 
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This should be cool to see.


Truck purpose: (Race, prerunner, rock crawler, other)
Approximate Wheelbase = 132"
Approximate Track width = 82"
Tire size = 35"
Trailing arm length = 49"
Upper link length = 41"

Frame side Link Info
upper link width/spread = 36"
Lower link width/spread = 42.5"
Vertical upper-to-lower link spread = 9"

Axle side info
upper link width/spread = 2"
Lower link width/spread = 52"
Vertical upper-to-lower link spread = 10.81"
 
I can post up my numbers later today but what I do know is a 1400 ranger I worked a bunch on had the upper link mounts INSIDE the factory boxed frame rails. First test it taco’d a 1.75”x.120 4130 upper link. Rebuilt them out of 2” .250wall but it would kill 1.25” Heims every 200miles and was peeling the top of pro-am housing off. Pocketed the link mounts into the frame and solved all the issues for 6k race miles. Still manged to destroy a 2” .250 wall upper link in a rollover. I was impressed the 3/4” RPI bolt didnt bend
 
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https://www.crawlpedia.com/4_link_suspension.htm
Also you can use this website and it has a 3/4 link calculator that you can put all your parameters into and it got you all your numbers
yeah, i've been using that. The calculator is mostly awesome - it unfortunately doesn't give you a basis of what works and what does not, though. So i'm hoping a data log of other people's setups will help people figure out what to shoot for in that calculator.

and aside from that, the calculator does not factor in lateral loads - which is what i'm specifically worried about and what Andrew 84Prerunner is describing.
 
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