Rear Springs - Low Budget

[rushcanuck]

Ok off topic of the Bilsteins, Im also about to make a purchase of sum rear springs. I priced out a set of deaver J40's and it came to $1000 plus $250 shipping to canada and at a just outta high school budget that really doesnt work for me. I contacted a friend who works for a spring shop and they said they will take a shot at a set of deaver copys at a discount price, talking about $500 for the set which I can do. However he needs sum measurements of an unsprung J40

A)is from the center front eyelt to the center of the centerpin bolt on the leaf
B)is if you take a straight edge across the eyelets down to the top of the top leaf of the pack
C)is the measurement from the center of the centerpin bolt to the rear shackle leaf eyelet
D)is the measurement from eyelet to eyelet
E)is the thickness of each leaf (aka 1/4")



if anyone could help me out and get those I would be absolutely thankful

[shockseals.com]

You will need 185lb/in unclamped rate with 12" of free arch for 4" of lift. 225lb/in if using a 4" clamp will be the clamped rate. The springs will grow from centerbolt backwards I think 2-3" over stock but dont quote me on that. If you make them too long they will buckle as they cycle flat.

That should be enough info for them to make your springs and get them on the truck and tweak from there.

[rushcanuck]

thanks, I emailed them with that info. hopefully we'll be able to build it from there

[rushcanuck]

ok well me and the shop looked at your info, were not able to understand the unclamped rate. and or able to find any sort of basemark for building the spring. the 12" of free arch was useable and we used the eyelet to eyelet from the stock spring which he has a blueprint for. From the pictures Ive seen we determined that the J40 has 10 leafs total, and they look approximately 1/4" in thickness each. however we will still need both measurements (A) and (C).

[Tchajagos]

http://broncograveyard.com/bronco/i-335 ... s-j40.html
Hey, check out the superflex springs on Jeff's bronco graveyard. They use j40 springs. Might be a cheaper option.

[shockseals.com]

ok well me and the shop looked at your info, were not able to understand the unclamped rate. and or able to find any sort of basemark for building the spring. the 12" of free arch was useable and we used the eyelet to eyelet from the stock spring which he has a blueprint for. From the pictures Ive seen we determined that the J40 has 10 leafs total, and they look approximately 1/4" in thickness each. however we will still need both measurements (A) and (C).

They shouldnt be making springs then!

The eye to eye dimensions decreases as arch increases so using the stock eye to eye and relaying it to the 12" free arch eye to eye isnt a good method. All you care about is lift height and that your axle is centered. THen you want to the rear half of the spring as long as possible but not too long that it is longer then the shackle causing the spring to buckle as it cycles flat.

.25" spring material is way too thick if you are going 10 leafs also the j40 is a 3" wide pack so unless your reduce the spring thicknesses from that pack 12"
of free heightwillbe too much becuase that pack is a larger rate then the F53 and why people are under the illusion that 3" springs have better roll control then 2.5" wide springs.

[shockseals.com]

one more important thing is that the stock leaf pack works pretty good with a good shock and bumpstop to my disbelief. A bone stock bronco with 35" tires and fiberglass preran the 1000 with my group. It had stock rear leafs with a 2.5" bypass and air bump, front was bone stock dual shocks with monroes(no joke) and he was an old desert racer from the 60s/70s (Wayne Cook) and he man handled that rig faster then most of the long travel rigs on the prerun so the stock sprigns can be made to work with the right shock set up and they are free.

[tcm glx]

one more important thing is that the stock leaf pack works pretty good with a good shock and bumpstop to my disbelief. A bone stock bronco with 35" tires and fiberglass preran the 1000 with my group. It had stock rear leafs with a 2.5" bypass and air bump, front was bone stock dual shocks with monroes(no joke) and he was an old desert racer from the 60s/70s (Wayne Cook) and he man handled that rig faster then most of the long travel rigs on the prerun so the stock sprigns can be made to work with the right shock set up and they are free.

That's killer...... 2.5" bypass on a stock leaf. Driver clearly also had impact.

[Dezertbronco]

macs spring re did my stock pack and added 2" of lift and re arched them, I ran them for years untill i found my race pack @ the swapmeet.


the stock pack will take a beating for sure....