GoFastBroncos.com

You would have to offset the springs quite a bit to fit the shocks outboard of the frame and have the leafs outside of that. It would be 4" at the VERY minimum. My guess is it would be closer to 6-8" depending on shock & if any of the shock body hung low enough to be there between the frame & leafs. You'd have to build the piss out of the mounts due to the leverage on extended mounts.

Why not just try & run the shocks outboard of the frame AND leafs? You'd be building custom shock mounts anyway, so why not save the hassle of moving all the leaf mounts around as well? I will note this still will be a tight fit and you'd be cutting in to/customizing your wheel wells a bit I'm sure. Upper shock mounts would be best tied into a cage above here obviously, but if you have a cage then you may not be still trying to hide the shocks "under the bed".

ChaseTruck754 wrote:You would have to offset the springs quite a bit to fit the shocks outboard of the frame and have the leafs outside of that. It would be 4" at the VERY minimum. My guess is it would be closer to 6-8" depending on shock & if any of the shock body hung low enough to be there between the frame & leafs. You'd have to build the piss out of the mounts due to the leverage on extended mounts.

Why not just try & run the shocks outboard of the frame AND leafs? You'd be building custom shock mounts anyway, so why not save the hassle of moving all the leaf mounts around as well? I will note this still will be a tight fit and you'd be cutting in to/customizing your wheel wells a bit I'm sure. Upper shock mounts would be best tied into a cage above here obviously, but if you have a cage then you may not be still trying to hide the shocks "under the bed".

Thanks for the response Steve! That analysis puts a halt to that idea. I figured the mounts would have to be strong but I didn't think the offset would be near 6".

No problem Will. Offset depends on shock location, but if you're trying to keep things "under the bed" then chances are very likely that the body of the shock would be between the frame & the leaf. I'm sure some people might squeeze things tight and maybe run a 4" overall spaced out leaf with a 2.5" smooth body shock but I wouldn't for sure. Things just flex & move too much to cut it that close in my opinion. I'd go 5" min. in that perfect situation. Add bypass tubes on the shock and things move even more.

his is how a Rapter has it's rear shocks, and one way to go similar to what you are discussing (I think).
https://www.youtube.com/watch?v=vnpI0O_RI0s

Maybe a dumb question and maybe I skipped the page with the answer but how much travel can you get out of the stock bronco springs once I pulled out my stock shocks I only got +1” of droop but the schacles are not flat gonna run a under bed cage longer shocks with stock springs for now? I would love to hear who runs 3” wide springs vs the q80 thanks for the patience

The stock springs have fewer and thicker leaves. They don’t flex very well so you are not going to be able to get them to droop out.

I have J40 springs that I am trying to make work on my project. They are 3” wide deaver springs for a bronco but have been de-arched by deaver 2”. I think they come as 4” lift or something. The problem I am having with them is they don’t droop out like the Q80s do and I am getting a lot less travel. The leaves separate a lot sooner. I made 8” long shackles and dropped the hanger and even moved the hanger back to where the shackles lay flat at droop and I’m still not getting as much droop at the Q80s get with extended shackles and dropped hangers.

This was around 15-16” from bump (on the frame)

Tchajagos wrote:The stock springs have fewer and thicker leaves. They don’t flex very well so you are not going to be able to get them to droop out.

I have J40 springs that I am trying to make work on my project. They are 3” wide deaver springs for a bronco but have been de-arched by deaver 2”. I think they come as 4” lift or something. The problem I am having with them is they don’t droop out like the Q80s do and I am getting a lot less travel. The leaves separate a lot sooner. I made 8” long shackles and dropped the hanger and even moved the hanger back to where the shackles lay flat at droop and I’m still not getting as much droop at the Q80s get with extended shackles and dropped hangers.

Thanks for the feedback Nelson I remember those shackles they looked sick what’s your thoughts on urethane bushings would they help here?

Here's some info for those on the fence about going through-bed or under-bed. I ran a study using Solidworks. I set up a kinematic study that has some hard values and some approximations. But all the components are accurate within an inch. That being said, I laid this out in a Bronco-like scenario with 3 different shock configurations on a truck running 64" leafs under-axle.

1) UNDER BED SHOCK - HI ANGLE
2) THRU BED SHOCK
3) THEORETICAL 1:1 SHOCK (NO ANGLES/LINEAR)

Overall travel is about 21" with a notch. The under bed shock would need to be at least ≈10" and the thru bed shock would need to be at least ≈18" in this particular scenario. I ran the study incrementally and recorded shock lengths at every inch of linear axle movement from full droop to full bump. Here is the data table and GIF of the kinematic study movement.





Suspension systems are non-linear/radial linkages, so the shock to axle movement ratio cannot be a fixed value. Knowing that, my goal with the study was to find the optimum shock setup and operating windows where the ratio's were most stable. The data/graph show the ratio change through each inch of linear axle movement. The lines on the graph represent these data points over one half of the cycle (full droop to full bump). The THRU BED configuration has a ratio improvement as you get closer to full bump while the HI ANGLE - Under Bed configuration has a degrading ratio which worsens as it nears full bump. This all has to do with the shock angle change as the suspension cycles. You can see in the kinematic video/GIF at full bump the THRU BED shock is at 90° to the linkage (leaf) while the HI ANGLE/under-bed shock is at a highly acute angle.

If you're not sure how shock angles affect your system here's a link I found that does a better job of explaining than I could: https://www.onallcylinders.com/2017/03/ ... d-springs/

They have a cool graph with what they call Angle Correction Factor.

After my quick and dirty study, I have decided to mount shocks through the bed. Luckily, I have a +9" housing so I can mount the shocks further outboard thereby limiting the intrusion into the cab. Under bed mounting still isn't a bad option, just know you're working with a ratio that averages under ≈0.5:1 (meaning for every inch of linear axle movement, your shock is moving about half an inch) and you'll have to valve more aggressively as you near full-bump to compensate for the degradation in ratio.

nicely done man!!

That is a nice study on the shock's under the bed verses through the bed.

Today I had the question of shock tuning pop in my head out of nowhere.

I am running 2.5" wide race packs from National Leaf Springs. They are a NOS set I was given when we converted the truck to a Class 8 with a 4 link rear. We had them as a spare set for a friend's full stock truck that are a little stiffer than a normal F150 leaf pack with double military wrap ends and so National said back then they should do well for a long travel Bronco.

I am running a set of King 3.0x18 non bypass reservoir shocks through the bed at a 1 to 1 ratio. They are a free hand me down from a friend when we changed his shock sponsor to Fox. Right now the shim packs for compression and rebound are set-up for a lighter leaf spring truck, so I need to change the shim's packs.

I was wondering what are you guys with a similar Full-size Bronco Setup running for the size of shim packs on compression and rebound?

Thanks
David

David Wright

new question.

Does anyone know what year's of Chevy trucks came with 64" leaf springs?

Other question, does anyone know what the Deaver part # is for the 64" springs used in long travel suspension like Giant motor sports uses?

David

Also, What is better for the Bronco, Deaver Q80 or J40. Or are both just ok. Whats the difference? I am leaning 64" from Geoff Falzone or 3 link. 3 link would be cheaper for me if metal prices stop going through the roof and the 64's would be $1400 for the leaf pack. I can fabricate everything myself.

What are your thoughts?

David

Wrightracing.net wrote: ↑

Wed Nov 22, 2023 4:44 pm

Also, What is better for the Bronco, Deaver Q80 or J40. Or are both just ok. Whats the difference? I am leaning 64" from Geoff Falzone or 3 link. 3 link would be cheaper for me if metal prices stop going through the roof and the 64's would be $1400 for the leaf pack. I can fabricate everything myself.

What are your thoughts?

David

From memory (and I stand corrected), J40's are a 3" wide spring pack with 4 - 4.5" of lift to fit Broncos and 4WD F trucks. The Q80 is a 2.5" wide, 4.5 -5" lift heavier duty spring pack for 2WD F trucks, and Broncos that need extra spring weight carrying more gear. Q80's will need spacers in extended Bronco or 4WD F truck 3" shackles or change the chassis hangers to fit 2.5" extended shackles.

AussieRod wrote:

Wrightracing.net wrote: ↑

Wed Nov 22, 2023 4:44 pm

Also, What is better for the Bronco, Deaver Q80 or J40. Or are both just ok. Whats the difference? I am leaning 64" from Geoff Falzone or 3 link. 3 link would be cheaper for me if metal prices stop going through the roof and the 64's would be $1400 for the leaf pack. I can fabricate everything myself.

What are your thoughts?

David

From memory (and I stand corrected), J40's are a 3" wide spring pack with 4 - 4.5" of lift to fit Broncos and 4WD F trucks. The Q80 is a 2.5" wide, 4.5 -5" lift heavier duty spring pack for 2WD F trucks, and Broncos that need extra spring weight carrying more gear. Q80's will need spacers in extended Bronco or 4WD F truck 3" shackles or change the chassis hangers to fit 2.5" extended shackles.

Thanks Rod
I currently have National Spring company Race Leaf packs. I have not run them yet, but they are 2.5" wide. They were a spare set for a friend's F150 Stock full race truck and he never used them and converted the truck to a Class 8 with a 4 link rear end. I already have some extended Camburg shackles for the Bronco.

I plan to run them in a spring under configuration to help combat negative arch problems at full bump.

I'm just looking into alternatives if I don't like the National's.

I like the setup Geoff Falzone has on his old Bronco with 64" rear spring under. It seems to work well.

I may end up just going to a 3 link.

David

No worries, Mate.