Another Leaf Spring Question

[paul8369]

I have a 1985 C2500 with an 8,600 lb GVW. From what I can determine, the truck came with the 3,500 lb springs (8+1 leaves). A PO replaced the rear axle, springs and 11-1/2" brakes. When this was done, a 7+1 spring pack was installed. I notice considerable sagging when pulling a 3,000 lb trailer or loading the bed. I am considering replacing the springs with a higher rating to return some of the truck's capability. I definitely need to replace the spring hardware because it is pretty rusty. BTW, I have replaced the small brakes with the 13" brakes to solve that problem.

Typically, I haul a few hundred pounds in the bed and a 1,500 lb total trailer load. A few times a year I haul 3-4,000 lb of dirt or mulch in a trailer. On occasion, I need to trailer a car. I am hesitant to load it heavier or run longer because I don' know what capability I have.

The springs on the truck are 56" with a total spring pack thickness of 3". The 7 springs are slightly less than 2-1/2" thick with a 9/16" thick overload spring. I have a parts truck with a 7+1 spring pack that is 3-1/4" thick. The parts truck has the same 7 spring thickness as on my truck with a 3/4" thick overload spring. So, the difference between them seems to be the thickness of the overload spring.

From looking at replacement springs, a 7+1 spring pack is 2-5/8" thick (give or take based upon manufacturer) rated for 1,950 lb. The next step up is a spring pack 8+1 that is 3-1/4" thick rated for 2,600 lb. The correct springs for my truck are 8+1, 3-5/8" thick and rated for 3,000 lb.

Here are my questions for you guys:
1. What rating will my current 7+1 spring that is 3" thick have? It would seem (assuming new springs are manufactured with the same materials and methods as the original) these are greater than 1,950 lb but less than 2,600 lb
2. What rating are the 7+1 3-1/4" thick springs? Could they be 2,600 lb springs?
3. If I go back to the 3,000 lb springs, how rough will the ride be?

Honestly, I would rarely take advantage of the 3,000 lb spring rating. The 2,600 lb rated springs seem to be a good compromise for me and how I currently or plan to use the truck. I don't want to buy a new set 2,600 lb of springs if one of the two sets I currently have are rated for 2,600 lb. I bought leaf springs for another ride last year and I guessed wrong on the springrate for that car. I don't want to make that mistake again.

I appreciate your help clearing this up for me.

 

[edgephoto]

Why not just put the stock springs back in?

 

[paul8369]

I started this assuming I would buy the 3000 lb springs. Once I got into it and saw the difference in the two sets of springs I already have and how new springs are configured I am confused. I don't know what spring ratings these truly are. Also, I see more posts about people wanting to soften the ride of their trucks and that makes me a little leery to put the 3000 lb springs on the truck.
If the springs on my parts truck which are 7+1 leaves and 3.25" thick are the 2600 lb springs, I would like to go with them as a good compromise for capacity and ride quality.
I also don't want to spend about $750 on new springs and find afterwards I made a mistake or find out that the parts truck springs would have suited my needs.
So, if any of you guys have any insight, I really would appreciate it.
Thanks,

 

[bucket]

Just have a spring shop add a leaf or two into your existing packs. Or you can do the same with your parts springs if there's any leaves that happen to be a length that will work well between your existing leaves.

 

[paul8369]

Thanks for the input. I decided since the entire truck is setup for the 8,600 lb GVWR, it is best to put the correct leaf springs on the truck rather than get too cute trying another configuration that may create new problems.

 

[Grit dog]

Thanks for the input. I decided since the entire truck is setup for the 8,600 lb GVWR, it is best to put the correct leaf springs on the truck rather than get too cute trying another configuration that may create new problems.

You’re way overthinking it. If you want to spend time and not a lot of money and get dirty wrenching then buy some new u bolts and add a couple leafs from whatever.
If you want to spend a bit more money and less time, rust and cussing, get an add a leaf, air bags, Timbrens etc. simple bolt on for a couple hundred bucks.
If you want to spend a lot, get new springs and have the same end result as the above options.
Think about roi. Is this a money making daily driver that you load heavy often and rely on and put a lot of miles on now (and for years and years to come)? Or in this a spare vehicle you use for projects around the house and dump runs?
How nice is the truck? Are you restoring it? Is it worth $$ and will be worth more if you spend $750 instead of $40 or $200?

 

[paul8369]

Thanks guys. I know I am overthinking it, but part of it is trying to determine what springs I have since I can't match them to any information I can find WRT leaf and springpack dimensions. I wanted to know where I am before I make any decisions.
With that said, I haven't done anything yet. Adding a leaf or air bags are probably the best solution in the end.

 

[Scruffy49]

My “money maker” is a 1t 4wd c&c dually. 5+1 mains, 3+1 overloads, 12,000# gvwr. And is undersprung, badly. I’m switching it to spring packs out of a C60 lineman’s truck with 40’ boom/bucket…

 

[Grit dog]

My “money maker” is a 1t 4wd c&c dually. 5+1 mains, 3+1 overloads, 12,000# gvwr. And is undersprung, badly. I’m switching it to spring packs out of a C60 lineman’s truck with 40’ boom/bucket…

wtf do you load in it?

 

[Grit dog]

Thanks guys. I know I am overthinking it, but part of it is trying to determine what springs I have since I can't match them to any information I can find WRT leaf and springpack dimensions. I wanted to know where I am before I make any decisions.
With that said, I haven't done anything yet. Adding a leaf or air bags are probably the best solution in the end.

It doesn’t really matter. How much rear spring do you need is what matters.
You’re 8600 gvw came with 8 or 9 leaf, idk, just drove mine for a couple hrs today. It’s stout as hell. Only flex is in the tires.

 

[Scruffy49]

wtf do you load in it?

Former welding truck with a 9’x7’6” steel flatbed. Gooseneck well built in, ball goes through a 3/4” thick base plate. 2 fuel tanks adding 60 gallons of weight, wrapped frame center… Wet curb weight is 8200#, the springs are shot. Truck needs to be lifted, my C60 got squished by a falling tree, I’m broke…