# Leaf spring rate

#### Loanranger

##### Member
I know I've seen it somewhere before, but can't find it from searching. Isn't there a general rule for spring rate in leaf springs? As far as how many leafs of a certain thickness will generate how much spring rate?

#### 4x4junkie

##### Forum Staff Member
Forum Moderator
TRS 20th Anniversary
This might help.

Its a bit tougher to calculate for leaf springs than coils though due to their tendency to be progressive (some of which is influenced by your shackle angle, and how much arch the spring has).

#### canyoncritter

##### New Member
ever notice thier "example" and equation dont match? 3inch wide spring in their example and a 2-1/2 wide spring in thier equation lol

double post

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#### Loanranger

##### Member
Thanks 4x4Junkie, looks like that will help.

#### Loanranger

##### Member
Wow. Wasn't till I did a google search that I found the Technical Library has a calculator. Seems like I looked there too and didn't find one.

According to the calculator, I have a spring rate of about 80 lbs/inch on the front of the Fordzuki, But I think something is wrong with the equation when I try for the 1/4 elliptical spring rate. (main and second ranger rear leafs cut in half at the center pin. length of 24 inches) It says the spring rate is 489 lbs/inch

#### 4x4junkie

##### Forum Staff Member
Forum Moderator
TRS 20th Anniversary
Dang, I didn't know that was there either (then again, Jim's been busy adding a lot of new stuff lately, maybe that was one of them lol)

Yeah, I seen the width error too (one of many that seem to get past those dudes over at Peterson's 4-Wheel magazine)