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Positive arch versus negative arch springs, which will last longer on a crawler?

Lil'John

Former #278
Joined
May 20, 2020
Member Number
488
Messages
1,047
Loc
Walking to the Rubicon
Title kind of states it.

Long:
I have an "off-shoot" project that is similar to an existing rig just much bigger tires but sheet metal cut. Current rig is 35" tires, spring over using 99 Tahoe springs. I love the ride height, flex, and ride.

Off-shoot project was going to go 35" tires but spring under with 99 Tahoes. My new tire choice needs a bit of lift but not a full on spring over amount(~5-6") So my choice is to go spring under with 2-3" lift springs OR spring over with 2-3" drop springs. The lift springs will have a positive arch and the drop springs will have a negative arch.

Which will survive lots of cycling on trails like Rubicon and Fordyce(technical crawling)?
 
I picture neg arches coming from sacked out springs. In that case they will have terrible wrap. But if they are designed that way and are adaquately stiff, then i guess it would be fine. You need to consider the spring rates and geometry. A positive arch pack has a progressive spring rate. And it's geometry is consistant and predictable. A neg arch spring will not be very dynamic at all. It will unload really easy.
 
Appropriate user name for the first reply:lmao:

Usually, I put more association of axle wrap to spring over than "similar spring rate" springs. But I 100% plan to run a wrap bar.

Any thoughts on running spring eye in a high position rather than low?

Here is Tahoe vs unknown:
springs_compare6_sml.jpg

springs_compare7_sml.jpg

The upper painted leaf in both pictures is an unknown Chevy main leaf that was about 56". The lower is a 99 Tahoe that is 54". As the pictures show, the Tahoe eyes being centered while the bottom picture shows the unknown having a lower eye.
 
can you not just move the shackles and hangers up a little? Shorten the spring perch?
 
can you not just move the shackles and hangers up a little? Shorten the spring perch?
I like the way you think.

However, I'm about as physically short for mounting as possible:
PerchTruss2_sml.jpg

I could french the hanger in a bit after cutting it off.

As for the "shackle", not sure what I can say:
slider2_sml.jpg


Basically, same comment as the spring hanger, I could french the leaf spring slider into the frame but loads of work ;)

For the spring over, the third trick in my bag is to go with "no space" spring perch; basically plate against the housing. This will shave about 0.5" to 1".

I'll admit, some of my interest in springs is being lazy and not wanting to cut shit out and potentially destroy parts:shaking::emb:
 
fwiw those shackle sliders are robbing you of down travel, not sure if it really matters for what youre building
 
fwiw those shackle sliders are robbing you of down travel, not sure if it really matters for what youre building
Not sure I really agree:
flex.jpg


Here is the drooped box:
droop.jpg

I ran into body and steering contact issues before I ran into flex issues. The second picture shows that I get half the travel out of the box as well as spring clamp contact. At full compression, the spring is at the very front of the box.
 
Appropriate user name for the first reply:lmao:

Usually, I put more association of axle wrap to spring over than "similar spring rate" springs. But I 100% plan to run a wrap bar.

Any thoughts on running spring eye in a high position rather than low?

Here is Tahoe vs unknown:
springs_compare6_sml.jpg

springs_compare7_sml.jpg

The upper painted leaf in both pictures is an unknown Chevy main leaf that was about 56". The lower is a 99 Tahoe that is 54". As the pictures show, the Tahoe eyes being centered while the bottom picture shows the unknown having a lower eye.
Easy there. You asked a loaded, retarded question. But I threw you a feakin bone. Now you're asking more stupid questions. Slider boxes really sums it up. :rainbow: why ask questions if you're going to fuck your cousin anyway?:flipoff2:
 
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