Author Topic: My guide to proper Leaf Spring setup  (Read 52798 times)

0 Members and 1 Guest are viewing this topic.

OldGold3VZE

  • Offline Crawler Guru
  • ****
  • Turtle Points: 4
  • Male Posts: 417
  • Member since Feb '08
  • Run whatcha brung, and have some fun!
    • View Profile
    • Light Racing, High Performance Bump Stops
My guide to proper Leaf Spring setup
« on: Jan 30, 2012, 06:10:03 PM »
This Thread is Featured in our Tech from our Forum Members section!



Now that I feel dedicated to this sport of Rock Crawling, have built many rigs, and truly feel that a properly suspended vehicle will make for a safer, more comfortable day of wheeling or road tripping I had few thoughts I'd share on how to set up a good suspension system using leaf springs and basic dampers and bump stops. 

1.  Set Ride Height 1st!! this is how tall the vehicle sits, too low and you will drag and have little to no up-travel, too tall and you will tip over easily and have minimal droop travel.  I don't go by this whole new "ultra low" trend, because I know that if my rig is 1-2" taller than some of these slammed crawlers riding on bump stops I will have more up-travel, resulting in my wheels continuing to travel up, while the super-low crawlers are now hitting their bump stops and getting ready to tip over.  I like spring rates that yield 1/3 up and 2/3 down travel.  You will have to make adjustments to your mounting points if desired ride height and wheel travel ratio (up vs. down) can't be achieved with the stock mounts.  Shackles don't always have to be at 45*.  If using a leaf pack that is built with lots of thin leaves that will flatten out quite a bit, like the popular "rears up front" springs then your shackle is responsible for much less droop travel then if using a heavy, 3 leaf pack that won't flatten out too much.  The latter style spring pack will benefit from a more slack shackle angle, simply due to the fact that the higher rate springs will not be under as much preload as the thinner, softer springs, and will not be in a position to release and offer as much down travel.

2.  Bump Stops.  You definitely want some nice forgiving bump stops.  Set them up to engage just as the springs get flat, accounting for the "squeeze" of the bump stop to just barely put your springs into a negative-arch position when fully compressed.  Taking the springs apart and only working with the main leaf can make this task pretty simple.  I have used the hard " black triangle" type bump stops, and they are quite harsh.  Yes, they keep your springs from over flexing, but can make higher speed offroading a nightmare.  Also, if you can disassemble your dampers go ahead and install some shaft bumpers.  Flex travel is different from straight on "speed bump" travel.  Sometimes, your main bump stop will be for speed bump hits, and the shaft bumpers will only engage when the axle is fully articulated.  Mounting the main bump stops a little inboard of the springs can help add to this effect.

3.  Dampers. Now that the vehicle is at proper ride-height, wheel travel ratio is set, and bump stops are in place, you can get your dampers installed.  You want the dampers to be as close to being inline with the wheel travel path as possible.  This allows the piston to move freely within the body of the damper, minimizing bind, which can wear out many components of the damper, shaft, inner body surface, piston band, etc.  It also allows the damper to work as it is supposed to, in as close to a 1:1 wheel travel to damper travel ratio as possible, not being over leveraged by being placed at an extreme angle, sometimes cutting damping characteristics in half.  With a leaf spring setup it is ideal to take the spring pack down to just the main leaf and allow the truck to rest on the bump stops, adding a spacer block between the main leaf and the axle mount to imitate the rest of the leaves.  Now you can get your dampers mocked up, and design an upper mount.  I like to depressurize my dampers, but if using a non-serviceable damper that can not be depressurized you can just ratchet strap the dampers down.  Right now, the truck is a full compression in a "speed bump" style bump.  This is different from a rock crawling type of "flexed out" articulating bump.  Articulation of the axle can allow the wheel to travel upward on one side of the axle once that side has engaged its bump stop while continuing to drop down on the other until the springs simply will not allow the lower wheel to droop anymore.  For this reason, you want to set your dampers to have 2-3" exposed shaft when at full compression of BOTH bump stops on a given axle.  Basically, if the weight of the vehicle is keeping the vehicle on the bump stops on all 4 corners you can now install your dampers with 2-3", I prefer 3", between the shaft and the bottom out point, not the shaft bumper (if you installed them) unless you are playing it extremely safe and running really long dampers. 

A few things to remember...

-The front dampers need to be slightly angled inward so that the tire does not rub the damper or possibly the shock hoop, while trying to achieve that perfect 1:1 ratio, and not interfering with the steering shaft or other items under the hood.

-If you are trying to use dampers that are too short, set them up to top-out, rather then bottom out since top-out usually occurs at slower speeds, and bottoming out usually occurs at high speed, which can blow up a damper and/or mount.  Obviously, if you are going through all the trouble of setting up your suspension properly then you are going to be using the correct length dampers, but just if...

-If this is a new rig build then you should also consider getting the steering set up at the same time.  It's nice to know exactly how close that drag link is going to be to the leaf pack, and the fact that your truck is going to be sitting at full bump makes this the best time to get everything perfect.  It also gives you an idea of how far back the axle will move during full compression.  Maybe you don't actually have to chop up your radiator core support so much or at all? 

-Spring clamps, yes, you need them.  They can and will save so much headache on the trail.  No more sledge hammering splayed out leaves, or broken leaves from de-arching on the trail. 

-Springs will settle.  Always keep some thin leaves on hand to adjust as necessary.  I have had to add 1-2 leaves to a spring pack after just 2-3 months of driving and wheeling to get back to my desired ride height. 

I would like to hear others input on this subject.  I know all the rage is going to links and air shocks or coilovers, but how many people have actually taken the time to really dial in their leaf sprung truck?  How many people are still running too short "white tube" dampers, bottoming out, running hard or worse no bump stops at all?  Who is fine with their leaf springs, and what makes them work for you?  Just some food for thought. 
« Last Edit: Feb 20, 2012, 05:02:09 PM by BigMike »
My 1980 Long Bed build thread
http://board.marlincrawler.com/index.php?topic=84562.0

Truggy build thread
http://board.marlincrawler.com/index.php?topic=89844.0

Rastafari Livity!  Ital = Vital!

spc mike

  • Offline Crawler Guru
  • ****
  • Turtle Points: 1
  • Male Posts: 428
  • Member since Apr '08
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #1 on: Jan 30, 2012, 06:15:10 PM »
Nice, Thanks!

yotacrawler1

  • Offline Rock Master
  • ***
  • Turtle Points: 2
  • Male Posts: 259
  • Member since Sep '11
  • 1985, on wontons
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #2 on: Jan 30, 2012, 06:48:55 PM »
love it

daniresch

  • Offline 4WD Legend
  • *****
  • Turtle Points: 930
  • Male Posts: 761
  • Member since Apr '11
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #3 on: Jan 30, 2012, 07:49:05 PM »
 nice write up :biggthumpup:
1988 Blue Std Cab: SAS, Longs, HP/ARB/5.29 Front, ARB/5.29 Rear, Marlin Dual Ultimate w/ 23 Spline MC07XD-R10, Marlin 30 Spline Front & Rear Output Shafts, Dave's Triple shifter, FROR crossmember, Bilstein 12" f+r, RUF w/ 63s, 7in bob, 40x13.5x17 MTR's on Racelines Monster Beadlocks 17x9.5

build: http://board.marlincrawler.com/index.php?topic=80954.510

yotacrawler1

  • Offline Rock Master
  • ***
  • Turtle Points: 2
  • Male Posts: 259
  • Member since Sep '11
  • 1985, on wontons
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #4 on: Feb 01, 2012, 06:29:23 PM »
god i love this  write up on springs hahah. oh and was wondering, im kinda newbish rig i have now is my first build. but if u could do a few more bullets on like different bushings and little more detail on shackles shackle angle double shackle or tera flex etc. idk unless theres already a thread up on that

OldGold3VZE [OP]

  • Offline Crawler Guru
  • ****
  • Turtle Points: 4
  • Male Posts: 417
  • Member since Feb '08
  • Run whatcha brung, and have some fun!
    • View Profile
    • Light Racing, High Performance Bump Stops
Re: My guide to proper Leaf Spring setup
« Reply #5 on: Feb 01, 2012, 08:59:01 PM »
god i love this  write up on springs hahah. oh and was wondering, im kinda newbish rig i have now is my first build. but if u could do a few more bullets on like different bushings and little more detail on shackles shackle angle double shackle or tera flex etc. idk unless theres already a thread up on that

Bushings, just grease and replace them every other season of wheeling, or maybe go 5 years on a DD or mild trail rig.  I've always had great luck with the Polyurethane bushings that almost every aftermarket Toyota vendor sells.  Use a flex hone with a 1.25" OD to clean out old spring eyes to get all the rust and crud outta there.  

Shackle angle was covered, but basically you want a 30-50 degree angle depending on the free arch and amount of sag your springs take with the weight of the vehicle.

I've never messed with a double shackle, or any other "alternative" shackle mount, like say a spherical eyelet bearing mount.  I've always had great luck with the more traditional setups, and really just heard too many bad stories about non traditional systems.

The best shackle is one that utilizes a sleeve spanning the width of the 2 bushings plus 1/8" with an OD to match the bushing hole, usually 18mm on our Toyotas, and an ID of 9/16" rather than a big 18mm bolt.  This allows you to tighten down your bolts nice and snug without crushing your bushings, very effective, great ride quality, longer bushing life, and much better flex, too.  This also eliminates the need for a welded in cross tube from shackle plate to shackle plate.  

I really love 5" shackles with soft, high arch springs that flatten out quite a bit when the vehicle is on all 4 wheels.  I also like very firm dampers, which tend to work well with this setup, since the springs themselves are usually quite soft.
My 1980 Long Bed build thread
http://board.marlincrawler.com/index.php?topic=84562.0

Truggy build thread
http://board.marlincrawler.com/index.php?topic=89844.0

Rastafari Livity!  Ital = Vital!

IXLR8

  • Offline Rock Crawl'n
  • **
  • Turtle Points: -1
  • Posts: 42
  • Member since Sep '10
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #6 on: Feb 02, 2012, 09:56:49 AM »
Good job! This should be in a sticky somewhere, you explained it well & it could/will help someone doing their first build (or second or third). Thanks for taking your time to make it happen. A big  :biggthumpup: to you!

DAILYspec

  • Offline Dusty Trails
  • *
  • Turtle Points: 1
  • Male Posts: 10
  • Member since Feb '12
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #7 on: Feb 11, 2012, 03:29:00 AM »
very helpful write up for a noob like myself :biggthumpup:

Rocksurfer

  • Momentum Man
  • Offline Gold Turtle Award
  • *
  • Turtle Points: 759
  • Male Posts: 13,855
  • Member since Jul '04
  • Lego Enforcement
    • View Profile
    • Spinnin4s 4x4 Club
Re: My guide to proper Leaf Spring setup
« Reply #8 on: Feb 12, 2012, 01:16:03 AM »
I think this needs to be a sticky!
The Ghost-Rider/Ghost Runner

No matter how far you fall, the ground will always catch you

yotacrawler1

  • Offline Rock Master
  • ***
  • Turtle Points: 2
  • Male Posts: 259
  • Member since Sep '11
  • 1985, on wontons
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #9 on: Feb 12, 2012, 08:51:20 AM »
I think this needs to be a sticky!
yeah x2

rapier46

  • Offline Rock Master
  • ***
  • Turtle Points: 221
  • Male Posts: 249
  • Member since Sep '10
  • Granite Guru
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #10 on: Dec 12, 2018, 08:45:01 PM »
I’m curious on where to start with a new leaf setup.

I have a 2003 Tacoma and I like the ride height. But the leaf springs sit inverted all the time and therefore it’s quite uncomfortable over rough terrain.  Which it sees a ton of.  Lots of droop but hardly any up travel since the leafs are already sitting in the up position.  I have oem leafs in the back


I want to keep this ride height. But want new leafs that will function correctly. 



Where do I start?   I was thinking Probably just get leafs, and see if I need to change up the front mount to keep it low and get new shackles and everything?  If I have to french the front into the frame and move the rear shackle mount that’s fine, I can do whatever is necessary.
« Last Edit: Dec 12, 2018, 08:52:43 PM by rapier46 »

Snowtoy

  • Offline The 2.5K Group
  • ****
  • Turtle Points: 1403
  • Male Posts: 2,582
  • Member since Sep '03
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #11 on: Dec 13, 2018, 06:23:19 PM »
It looks like the shackles are already near the extent of their range, they shouldn't be that flat.


Is the bed loaded with weight?

If it is empty, have you checked to see if the main leaf springs cracked?

With not wanting any lift, I would start with a new set of springs for your quad cab, and if you carry a lot of weigh all the time, add an additional main leaf springs, they will increase your carrying capacity about 400lbs, and wont stiffen the ride that much when empty.
'90 black X-cab mod'd 3.0, 33's/4.88's, rear ARB, custom bumpers, sliders, safari rack, etc.
'91 Blue X-cab 22re, 35's/5.29's,Truetrac front, ARB rear, dual cases, and custom Safari flatbed, bumper, interior.
The money pit '87 Supra resto/mod

rapier46

  • Offline Rock Master
  • ***
  • Turtle Points: 221
  • Male Posts: 249
  • Member since Sep '10
  • Granite Guru
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #12 on: Dec 13, 2018, 06:52:04 PM »
It looks like the shackles are already near the extent of their range, they shouldn't be that flat.


Is the bed loaded with weight?

If it is empty, have you checked to see if the main leaf springs cracked?

With not wanting any lift, I would start with a new set of springs for your quad cab, and if you carry a lot of weigh all the time, add an additional main leaf springs, they will increase your carrying capacity about 400lbs, and wont stiffen the ride that much when empty.

Yes this is loaded. with what i carry constantly, spare tire, tools, recovery gear, bed cage, chainsaw, fuel.  350 lbs ish.  And it always in there. Leafs look like this



From the front mount pictured here, they go up, to the axle, then straight back to the shackle.  Definitely getting new leafs. But they’ll give me. Whole bunch of lift in the back if they held their arch.  Know what I mean? 

rapier46

  • Offline Rock Master
  • ***
  • Turtle Points: 221
  • Male Posts: 249
  • Member since Sep '10
  • Granite Guru
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #13 on: Dec 13, 2018, 08:00:19 PM »
Here’s my actual leafs tonight.


:)bestgen4runner

  • Offline The 1.5K Club
  • **
  • Turtle Points: 2120
  • Male Posts: 1,794
  • Member since Mar '16
  • Crawling with Marlin
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #14 on: Dec 14, 2018, 10:58:00 AM »
 :yikes: WOW!
I am 1/5th of Perfect Fit
SqWADoosh [04:19 PM]: *sigh* I guess Chris is right and I just need to wait until I'm in a place where I have a tow rig and trailer before I get this caliber of truck
Mudder [08:28 PM]:   not try to be a jerk, but are you serious bestgen?
Prismo [06:11 PM]:   Done, time to relax or as Bestgen says....FREEDOM!
HogCanyonHopper [06:54 PM]:   I like my little rod. it gets the job done
H8PVMNT [03:30 PM]: I can go both ways.

joeyf

  • Offline Rock Master
  • ***
  • Turtle Points: 848
  • Posts: 271
  • Member since Dec '06
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #15 on: Dec 14, 2018, 02:34:03 PM »
The ride hight looks great would suck to loose it. Most likely have to do what you are thinking, french the front with maybe 3 inch leafs.

300k

  • Offline Crawler Guru
  • ****
  • Turtle Points: 3744
  • Male Posts: 623
  • Member since Jun '15
  • GREEN NAME MAN BAD!
    • View Profile
    • Please ban me!
          OK!
      I am banned!
Re: My guide to proper Leaf Spring setup
« Reply #16 on: Dec 14, 2018, 02:40:53 PM »
take the bump stops off. your springs are already ruined lol
:)bestgen4runner [12:45 PM]:   I am so stupid.

Truer words have never been spoken...

rapier46

  • Offline Rock Master
  • ***
  • Turtle Points: 221
  • Male Posts: 249
  • Member since Sep '10
  • Granite Guru
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #17 on: Dec 14, 2018, 06:29:01 PM »
Thanks for the info gentlemen.   Yes I will do anything to prevent losing this ride height.

take the bump stops off. your springs are already ruined lol

What bumps?  Lol the rubber deteriorated and I have none.    New bumps go in with the u bolt flip and springs though!

300k

  • Offline Crawler Guru
  • ****
  • Turtle Points: 3744
  • Male Posts: 623
  • Member since Jun '15
  • GREEN NAME MAN BAD!
    • View Profile
    • Please ban me!
          OK!
      I am banned!
Re: My guide to proper Leaf Spring setup
« Reply #18 on: Dec 14, 2018, 06:33:18 PM »
What bumps?  Lol the rubber deteriorated and I have none.    New bumps go in with the u bolt flip and springs though!

Oh right on. Was looking at the first picture and thought the rough ride was caused by the 3/4 inch of available up travel haha
:)bestgen4runner [12:45 PM]:   I am so stupid.

Truer words have never been spoken...

rapier46

  • Offline Rock Master
  • ***
  • Turtle Points: 221
  • Male Posts: 249
  • Member since Sep '10
  • Granite Guru
    • View Profile
Re: My guide to proper Leaf Spring setup
« Reply #19 on: Dec 14, 2018, 06:43:40 PM »
Oh right on. Was looking at the first picture and thought the rough ride was caused by the 3/4 inch of available up travel haha

Haha!  Yeah.   I bet it is.  But that’s a photo I got from google.   Mine is worse lol   :gap:

 
 
 
 
 

Related Topics

1 Replies
2593 Views
Last post Jul 02, 2004, 02:15:58 PM
by Brandon
5 Replies
6412 Views
Last post Aug 09, 2004, 01:36:33 PM
by Bazzi
10 Replies
14552 Views
Last post Mar 10, 2006, 01:10:20 PM
by biff
16 Replies
5257 Views
Last post Feb 24, 2011, 04:05:33 PM
by awhotrods
3 Replies
2257 Views
Last post Jun 25, 2014, 09:17:51 AM
by lostbuckaroo