5.04 Leaf Springs & Shackles GURU Level Tech!

I learned so much from making this episode. I go DEEP into the tech behind leaf springs, shackle lengths and shackle angles using my homemade Bored o' Leafs. I hope you get something out of it!

Here is the formula I used

H = Sin(A) * L

Or, where SpL = spring length (dead flat), and MH = the distance between spring mount and shackle hanger:

MH = SpL - Sin(A) * ShL

[jpmc]

Don't apologize for the color! That pale yellow is rad!

[javierzuniga]

Wow!!! Why didn't I find this video before!!! This is gold to me!!! My old F350 rides like an old wild west chuck wagon. Thanks so much for this video!!! 👍👍👍

[matthewmugar]

Matt...one of the best videos ever put out on suspension. It's been such a mind boggle to understand this. This makes it totally comprehensible. thank you.

[legendroman]

No one could explain my question but you did .
Thanks for that paractical example. With out it i couldn't decide what to do.

[tundraspecialops]

Excellent demonstration on how leaf springs and shackles work!

[dineshkumarhariharan]

You cracked the real puzzle of leaf spring stiffness relationship wrt shackle angle.

[montanamanbuilds]

Thank you for to the point and no off topic ramblings! Logic was telling me that diagram was wrong.

[NAPAuniversalJoints]

Great video bud. i have always eye balled the shackle angle and run flatter springs. Usually works really well.

[shawnmancebo]

Hi Matt,
Enjoyed the info, one thing to help test spring compression and angles
Is to disassemble the both spring packs, using only the main spring and make a small block to replace all the other springs that have been removed, so if it 3 inches of spring that have been remove add in a 3 inch block put your bolt back though the block and main spring mock both springs on the vehicle than with a jack you can compress and release and let hang and get your angles of the shakles and find your bottoming points with your tires on and off as well and side to side relaesd and compressed with out the resistance of all the srings as well as measurements for shocks and brakes line mods, drive line lengths and so on
Thanks for the video!

[adambatchelder]

Great video, not a lot of people running leaf springs in off-road anymore. Ive got some custom made national springs in my chevy 4wd super long and super soft . I love them.

[jaydog]

I’m not a leaf spring guy at all, but now I feel prepared to become one of the day comes! Thanks professor.

[cdeprima]

Great video, I watched it a few times to realize I can change leaves to fix that shackle angle! Great job, thanks! :)

[ray]

Thanks for the leaf spring demonstration, I just checked the 55 truck rear leaf spring shackle I put on 10 years ago, it's straight up & down, there's another hole on the bracket that will change the angle to more movement. Now I know why I hit my head on the ceiling when I drive over a dip too fast. Thanks

[kevindegroff]

Outstanding video Matt! I have been building leaf spring Jeeps for years and only 'educatedly guess'ed' the shackle length and location. But now I have some good reliable math to use to take out the guesswork! (Yes, I can do math!) Loved the part "but wait!" I have watched this video about 5 times to make sure I understood and laughed every time!!

[Slowlane]

I have all my parts together to do a leaf spring swap on my CJ and wanted info on shackle angle. Best I could find so far was avoid inverting. This helps a lot. Thanks.

[raj]

Thanks for the informative leaf spring & shackle video. I dig the color of your scout.

[FlyLan]

As long as the information is correct then this is a great video. Gave me a expanded understanding and reinforcement for my spring suspicions. There are still a lot of questions I have about how various leaf pack mods and setup alterations will achieve different application goals. I think the main scenario that comes to mind is how a longer shackle will affect perceived on-road ride comfort when installed on the same leaf pack and using the same mounting points. This would be ideal for a DIY mechanic with basic tools and a limited budget that wants a more comfortable on-road experience with zero to little (driver+personal items/tools in cab=200-300lbs) additional payload. The problem I've been having is trying to get a smoother on-road ride quality out of a 2003 PreRunner TRD Double Cab. It has thick 3/1 two stage over-spring leaf packs. I'm unsure of the spring rates. Every aftermarket suspension component available for this truck is for lift, load, and/or off-roading/overlanding which all seem to equal a harsh on-road experience unless you're willing to drop $3k+ on 2- or 3-way adjustable reservoir coil overs and shocks and another $1k+ on progressive leaf packs, but even then you'll end up with a 3"+ lift with a 500-1klb payload increase which will then require new control arms, brake lines, diff drop kit, panhard correction kit, new ball joints, an alignment...the list goes on and on. You can do all that to this truck, but so far I haven't found one stitch of information about how to improve the ride quality for a daily driver aside from the snarky comment of "leave it factory". I refuse to accept this.

[conquest]

Thank you. This is the only precise video on this subject in the entire internet.

[Kactapuss]

Thank you. you really illustrated how the leafs and shackles interact on a leaf suspension. learned a lot

[ZJ_Rubicon]

This is very interesting. I am in the process of doing a 63" spring swap on my Tacoma so this information is very useful. Thank You!