So I'm going to install my 3rd set of springs(4th counting stock) and I am still struggling on finding the right springs for my needs. We have information scattered all over the place but very difficult to reference. So I am hoping to create a repository of technical informations so selecting springs for the 80s would be a breeze.....hopefully.
Key information are vehicle weight per axle and spring rate and how they can be pairs together. For example I went to truck stop and found out my front axle is currently at 2950lbs and rear axle is at 3100lbs. So what spring/spring rate should I use? I can't find any information on this so hopefully I can create a table of that here for reference. So hopefully once we find out how much per axle weight is and we can easily select the right spring rate and height. This should take out any guess work needed for selecting springs previously.
To get the "right" spring for the weight we need to find where ideal sag is. shocks is our travel limiting factor so it dawned on me that we should use our shock to measure where we our static sag is at. Most 0-3 inch 80's dampers are about 10 and 9 inches of full travel front and rear respectively, 4-6 inches lift dampers are about 11 and 10 inches of full travel front and rear respectively. This means if I want 6 inches of sag on 10 inch travel shocks I should have 4 inches of travel/shock shaft left on the shock.
To sum it up the ideal spring for an 80 is the one that provides static sag of ~30-40% of suspension(shock) travel and below 3 data reference points will help us get there:
1. Spring rate
2. Vehicle weight/per axle weight
3. Shock/suspension length
We need about about 5-6 inches of shock shaft exposed for 0-3 inch lift shocks and 6-7 inches of shaft exposed for 4-6 inch lift shocks. More shock shaft exposed means the springs are too stiff and losing droop and too little means the springs are over laden.
Please help contribute to the thread and I'll add them to the top so it can be easily searched.
Reference table:
Front axle weight------Ideal spring rate(standard overland use case)
2500-2700lbs----------220lbf/in ?????
2700-2900lbs
2900-3100lbs
3100-3300lbs
Rear axle weight-------Ideal spring rate
2500-2700lbs----------250lbf/in ?????
2700-2900lbs
2900-3100lbs
3100-3300lbs
Key information are vehicle weight per axle and spring rate and how they can be pairs together. For example I went to truck stop and found out my front axle is currently at 2950lbs and rear axle is at 3100lbs. So what spring/spring rate should I use? I can't find any information on this so hopefully I can create a table of that here for reference. So hopefully once we find out how much per axle weight is and we can easily select the right spring rate and height. This should take out any guess work needed for selecting springs previously.
To get the "right" spring for the weight we need to find where ideal sag is. shocks is our travel limiting factor so it dawned on me that we should use our shock to measure where we our static sag is at. Most 0-3 inch 80's dampers are about 10 and 9 inches of full travel front and rear respectively, 4-6 inches lift dampers are about 11 and 10 inches of full travel front and rear respectively. This means if I want 6 inches of sag on 10 inch travel shocks I should have 4 inches of travel/shock shaft left on the shock.
To sum it up the ideal spring for an 80 is the one that provides static sag of ~30-40% of suspension(shock) travel and below 3 data reference points will help us get there:
1. Spring rate
2. Vehicle weight/per axle weight
3. Shock/suspension length
We need about about 5-6 inches of shock shaft exposed for 0-3 inch lift shocks and 6-7 inches of shaft exposed for 4-6 inch lift shocks. More shock shaft exposed means the springs are too stiff and losing droop and too little means the springs are over laden.
Please help contribute to the thread and I'll add them to the top so it can be easily searched.
Reference table:
Front axle weight------Ideal spring rate(standard overland use case)
2500-2700lbs----------220lbf/in ?????
2700-2900lbs
2900-3100lbs
3100-3300lbs
Rear axle weight-------Ideal spring rate
2500-2700lbs----------250lbf/in ?????
2700-2900lbs
2900-3100lbs
3100-3300lbs
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