LEAF SPRINGS DO THEY SUCK?

ADSRACINGSHOCKS

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Jan 16, 2023
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NO OF COURSE NOT!​

There are many opinions both good and bad revolving around leaf springs, the simplicity in design has many advantages for some, other scoff at the idea of them. Here are some realities to let you decide for your self if they are the best option.

  • Cost There is no denying that leaf springs are more cost effective than a link style suspension, in some cases only slightly, custom springs for special applications can get very pricey but will nearly always beat out the cost of link type suspension.
  • Simplicity Since the spring locates the axle and provides the load carrying there is no need for an addition spring system such as a coil-over, on our tow rigs we do add supplemental load support with air bags or overload springs generally not used in performance applications.
  • Axle wrap One down side to relying on the spring to locate the axle and provide support, and being able to move is that, the pack is able to twist under throttle (axle wrap) this situation is not ideal but normally does not cause many issues, if axle wrap is too severe a torque arm can be added to eliminate this issue but it does add complexity to the system.
  • Packaging As most vehicles come stock with leaf springs packaging is nearly seamless, whereas link suspension generally requires relocation of fuel tanks and crossmembers.
  • Overall Travel With leaf springs we have a few limitations on available travel from any given pack, those factors are, free arch of the spring and shackle orientation/length. In the diagram below you can see the spring with the larger free arch as more travel potential, this spring will also increase its length more as it compresses which changes wheelbase more throughout the cycle.
  • This added length will also require a longer shackle to allow uninhibited travel. Think about a Deaver F67 on a Tacoma they run 11-13” shackle length, Where a stock style Tacoma may have a 3-5”1675203704033.png

  • Your short free arch spring will generally be found as a spring over axle configuration, and high free arch as a spring under axle configuration.

  • Anti-squat is also effected by which type of spring configuration is used, spring over axle will generally has less anti squat than a spring under, due to the moment arm geometry changing between the two. This factor all depends on how much power you are providing to the moment arm. See diagram below.
  • 1675203607300.png
  • (These examples are extreme to easily display the differences)

  • Shackle type, there are 2 common types of shackles being used today. Tension and compression style. See diagram.
  • 1675203742652.png
  • You can use either type on both spring types, but packaging will change for each. There are tricks to gain additional droop from a tension style shackle, personally I am not a fan of them as it is “dead” travel with no spring rate pushing out, you are solely relying on gravity to pull the axle out, not thing wrong with it but it does not stay active in deep whoops, which is why they need very little rebound control on droop. A compression style shackle will stay under spring force just until to reaches its free arch, which may be less overall wheel travel but has spring force through its full cycle aiding in traction.

  • Which is best for your application? That will be up to the vehicle and effort your willing to put into the combo, most bolt on kits are pretty close to ideal for the platform. Staying spring over normally means no fabrication or welding but to get more free arch you may gain ride height so keep that in mind, bolt in shock options are available for these “extended travel” springs. Going spring under will normally unlock more up travel as well as droop, but will require some fab work in the form of spring perches and shock mounts, normally when doing spring under your going to a bed cage and a 16” or 18” shock obviously of the ADS 5 tube flavor 😊
 
The longer the truck, the more leaf's start to suck. Shorter with weight is magic!
My stock Bronco that has a 4.0" with the bleed hole closed will murder a lot of 1400 trucks!
 

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I came to dislike leaf springs after helping a friend with them on a 1450 truck campaign a race season with them, and seeing how much maintenance they needed. The springs were off to Deaver every other race and the bill was a minimum 500$, when I raced my link setup went a whole season with needing little to no maintenance and what maintenance there was I could do myself and cost was very little. in my experience if you use your truck often and drive hard the long term costs of LT leaf springs can be more expensive than Links. Furthermore, if you break a leaf spring on a trip there is little you can do to trail fix it. On the other hand if you break a link setup on the trail and have a welder you will likely be able to cobble something together.
 
^^^ This!!! ^^^

He hit the nail on the head. If you use your truck often and/or hard, in the end, leafs are a pain in the dick. Breaking a main leaf VS breaking a coil spring in terms of hassle and money is a deal-breaker for me (and Im currently on leaf springs). As is getting the leaf springs prepped or re-arched.

Broken leaf = lifting those heavy ass springs/packs into your DD and taking them to deaver (in traffic, because the shipping costs are astronomical) so you can spend $400+, just to drive back to deaver a few days later and kill even MORE hours of your day sitting in traffic so you can get home to smash your fingers putting it all back together whilst wishing you could burn the truck to the ground...
**OR**
Broken coil spring = ordering a pair of coils (or just one if you like to roll the dice I guess) from your phone to have it/them show up a few days later delivered to your house, so you can disassemble and reassemble w/in the same day and be back in business for $100 +/-.

I wont build another leaf sprung truck. IDGAF if my link set-up is "only" pulling 18" of travel, I would still go links VS leafs.
 
They do suck on longer wheelbase or racing prep. but pretty dam fast, easy and affordable on heavy short trucks!
 

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Every time I see the title of this thread in the New Posts section, I think “Yes. Yes they do.”
Exact same. I would run them on a Bronco/blazer like @Giant Geoff suggested. Nothing else. I ended up running them for years on my Turboyota with limited success because:
1. I had F55 deavers sitting in the yard
2. The z-link setup I had planned to run wouldn’t work without a wider rearend.

The truck was fast and nimble through everything besides large whoops and big holes, but without a doubt 7” of up travel is gay.
 
^^^ This!!! ^^^

He hit the nail on the head. If you use your truck often and/or hard, in the end, leafs are a pain in the dick. Breaking a main leaf VS breaking a coil spring in terms of hassle and money is a deal-breaker for me (and Im currently on leaf springs). As is getting the leaf springs prepped or re-arched.

Broken leaf = lifting those heavy ass springs/packs into your DD and taking them to deaver (in traffic, because the shipping costs are astronomical) so you can spend $400+, just to drive back to deaver a few days later and kill even MORE hours of your day sitting in traffic so you can get home to smash your fingers putting it all back together whilst wishing you could burn the truck to the ground...
**OR**
Broken coil spring = ordering a pair of coils (or just one if you like to roll the dice I guess) from your phone to have it/them show up a few days later delivered to your house, so you can disassemble and reassemble w/in the same day and be back in business for $100 +/-.

I wont build another leaf sprung truck. IDGAF if my link set-up is "only" pulling 18" of travel, I would still go links VS leafs.
if links are so easy.... how come non of your trucks have them...
 
if links are so easy.... how come non of your trucks have them...
🖕

I setup my p/u with a very limited budget 16+ yrs ago... I had no idea what I was doing back then and everyone said I'd be happy on leafs.

The 4runner started out as a "simple" truck that was never going to be/get as built as it is now.

That said, when are you coming up to setup the link pivots on my p/u so I can get these things off my garage floor?
 
🖕

I setup my p/u with a very limited budget 16+ yrs ago... I had no idea what I was doing back then and everyone said I'd be happy on leafs.

The 4runner started out as a "simple" truck that was never going to be/get as built as it is now.

That said, when are you coming up to setup the link pivots on my p/u so I can get these things off my garage floor?
lets do it..
 
For racing I personally wouldnt run leafs, unless the class dictated that, because I raced with links for years without any major prep besides a couple heims that developed some play over a season of racing.

Properly sprung and valves leafs works awesome and make the whole build much much cheaper. I ran f67 deavers on my Tacoma for years and had to do 0 prep on them for the 2 years I ran them, but again I was just using the truck as a prelander truck and didn't care if I went slower through big holes, which we didn't plan on running through those holes on the trips I went on. My brother's 01 Silverado has spring under deavers and works very well even without proper valving. Leafs were simple to setup on his truck, just spring perches, shackles and hangers.
 
I am setting up my shocks and bumps on a leaf sprung truck right now, is it worth over cycling the leafs for about 3" of additional up travel or should set the bump to where the leaf is flat? Would over cycling them cause them to fail pretty quick? (Arch goes negitive).

Screenshot_20231226_123225_Brave.jpg
 
Consult your leaf spring MFG'r to confirm but from speaking with Deaver about Rangers, F-150's, and other trucks where the leafs go negative to get the axle to touch the frame, you are fine to fully bump the truck to the frame and the leafs are designed to handle that. That is staying within the design parameters of the leafs however adding a frame notch and pushing the axle further upwards will fatugue the leaf springs prematurely.
 
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