Spring rate change help...

Fifty

Well-Known Member
I have a 5.6x inch travel shock. Truck weighs 4200 plus spares and me.
The coilovers have 16 inch 650# springs and I’ve pulled all the preload out. I’ve only got a thread or two... so no more. But it’s sitting too high.

The coilover shaft and spring measurements With the truck on the ground are:
12.75 spring length

4.25 shaft showing from the silver flat washer under black bump to blue dust cap

3.75 From thenspring cup to blue dust cap.

the truck clanks and rides like poop because it has no droop. The truck is also sittingnose high and it needs to come down an inch and 3/4 to 2 inches... so about 1 to 1.5 inches at the shaft.

a 14 inch spring I don’t think will work because the preload will cause the spring to block out before full compression, so I think I have to stick with a 16 inch spring...

but will a 600 spring allow the needed lowering or will I need to run down to a 550?

anyone have pair of springs for sale?
 

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partybarge_pilot

Well-Known Member
According to my maths, a 500# spring would make it sit 1" lower on the shock. This may not leave you enough spring rate though. You would be better off with a 14X650 and a tender spring.
 

partybarge_pilot

Well-Known Member
Edit, something isn't adding up.

spring 16"
spring length at ride height 12.75
=
Spring collapsed 3.25"

Shock 5.6X" travel
4.25" shaft showing t ride hieght.
=
1.4" of travel.

So do you really have 1.85" of preload?
 

Fifty

Well-Known Member
I need to jack the truck up and re measure that. But it’s the minimal amount of preload on the passenger side. And the drivers side which the numbers listed are from; has the the most preload of the two.

I have a feeling I’m going to be at 16 inch 550#
 

Fifty

Well-Known Member
Heard back from filthy. They said go with a 550....

So now to see if anyone has any 3” ID 16 inch long 550# springs for sale. Or if I need to buy new
 

Fifty

Well-Known Member
Spring length at ride height is 12.75 and at droop is 14.25 inches

That’s a 16 inch 650lb spring.
 

Fifty

Well-Known Member
Or a 500 spring... that should reduce the shaft height by a full inch at ride height...
14.25-11.75= 2.5
So 2.5 for droop and 3.1 for compression...
 

Fifty

Well-Known Member
That should have read: ordered a 500 spring.
 

Fifty

Well-Known Member
I threw on the 500’s today. I ADDED 2 full turns of preload to the drivers side and 1 full turn to the passenger side.
I drove it for a quick minute, the radiator fan issue means I couldn’t go hammer on it, so just the typical 15 large speed bumps at 30-40 mph.

got back and measured, both sides dropped even. 1 inch.
I was surprised it was an even drop left to right lol. I’m hoping it will settle another 1/3-1/2 of an inch. We shall see.

tomorrow is to try to solve the spal fan conversion
 
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