Why shackles instead of blocks

I'm liking your way of thinking!!! I'm thinking about lowering my ToyTec shackles down to the 1" setting. With the AAL I have too much rake. I've got time this weekend to take care of that.

 

I am on Tundra number 5, all have had either a 1” or 1 1/2” non tapered block with no issues. So 200k plus trouble free miles on blocks, and imo option 2(more $) would be AAL or replacement springs, and this is why. Shackles and tapered blocks change the pinion angle. Pretend the engine/transmission in this picture is the carrier bearing. Flat blocks, AALs, and replacement leaves don’t alter this, or very little.

Again, my opinion, but the whole rear drive shaft on our trucks leaves me with a few whys?, but it works. Small shackles would not be bad, and some replacement packs need a small shackle. Factory shackles limit the maximum length the spring can flatten, add a 1 1/2” lift shackle and now your spring has more up travel, and can flatten out more due to the extended length of the shackle. That’s why springs fatigue and lose lift faster with longer shackles. No matter what there may be a vibration, but I would recommend shimming the carrier bearing to find a sweet spot before tapered shims etc..

 

I plan on lifting the rear of my truck with a shackle around an 1 1/2” but I will compensate for the extra travel with an extended rear bumper stop. I think this is the solution. So you think a carrier bearing drop is a better solution to a tapered shim on the axle?

 

Yes, both do the same, but if you end up with a vibration it is easier to experiment with varying carrier bearing shims opposed to picking a tapered shim for the rear and hoping it is right. We bit of a pain in the butt to swap the rear shims also. There will be no x does this and no more vibration, varies truck by truck.

 

I’m runningTRD exhaust with ToyTec shackles.

 

I knew a few of you were using the TTec's and TRD with no problems.

 

Are running the shackles at 1" or 1.5"?

 

1.5". I have a custom dual exhaust and the shackles do not interfere. I am lowering the shackles to 1". I like rake but a bit too much rake right now. My weekend project.

 

Yup I live in the Land of the Bro lean "East County" LaaakeSyyyyydee

 

1.5. Middle setting.

 

I regret them because I would have far better benefited from an aal then what I got from the shackles. They are fine and do what they are meant to do just personally feel like I would have been better off the other way

 

It all depends on use/need/$. AAL installation is a bit more involved than shackles. Not as much DIY as shackles can be.

 

Agreed - you need to look at how you use your truck and pick the option that best fits your needs. For me, I only drive 500-600 miles a month and most of that is city driving to/from my kids school. Hauling is the occasional Home Depot run and toting my kids swim gear (bulky but not heavy) and towing is a little pop up trailer. I think for my use shackles will be fine.

 

While my truck is going to be an every day vehicle driving 5 miles to work and back with random city driving, I'm planning on using it as my weekend offroad vehicle taking it on medium difficulty mountain 4x4 trails in Colorado and offroad camping trips. I just moved to CO and am going to be hittin the mountains as much as I can. I don't want to wear out those leaf springs by adding just shackles due to the 4x4 trail driving I plan on doing and the concerns of hitting the tailpipes...so leaning towards those fat Bob's Garage 1" blocks that @Vizsla has OR those Icon AAL.

 

The quality of the fat bobs 1” block kit is great. I think others use Tacoma blocks for Tundras or vice versa, but these fit better. The u bolts are oe quality, with the proper extended nuts for u bolt application. Great product imo.

 

Does anyone know if the Icon AAL will help with the weight of the full fuel tank? I know AAL can help with load capacity and the tank is kind of further back towards the driver side rear wheel. After my shop installed my Fox 2.5 coilover IFPs I have a pretty significant driver side lean (.75" lower on the driver side). It isn't as bad with a half or empty tank.

Also do the Icon AAL sacrifice ride quality? my shop said that AAL will negatively effect ride quality and that they'd lead towards doing blocks for this reason...

 

The way I’ve read it is, a shim on the front left CO would be more beneficial to correcting the issue believe it or not. I think I’m pretty lucky my truck sits on most perfectly level side to side when I measured it the other day front and back. It was a little more than half a tank of fuel so it might go down a little, but wouldn’t be enough for the shim to not push it in the other direction and be higher on the driver side. A 1/4” shim will lift it a 1/2”

 

With 5100 shocks in the rear, is it safe to put @Toytec Lifts shackles at 1.5” setting?

 

I have 5100s on the rear and a wheelers add a leaf. It was supposed to lift only an inch, but i got two inches out of it. Haven't noticed any issues so far but ive only put 2k on it since the lift/shocks were installed.

 

Thanks for the feedback!

 

A small block is fine. I ran a 1in on my truck for a year or so then switched to a 1in shackle and honestly couldn’t tell any difference. I think when you go over 1.5” is when you can start to tell big differences. Both are fair simple to install. I’ve also heard blocks wear our your leaf pack faster but, again I think that’s when you start really getting high uo there.

 

I read through this, but I’m not sure I saw anyone explain why blocks are bad. So here is my attempt:

The reason blocks on leafs are bad is because it effectively extends the distance of the centerline of the bore in the axle tube housing to the true center of the spring, affecting the moment arm and creating leverage for the tire to overcome the spring force.

Now, why is this bad you ask?

As a side effect of the rotational forces of the driveshaft spinning your tires and creating forward movement of your truck, generally the pinion tries to point upward. Meaning the springs are arched in a S pattern, so front of the spring goes up and rear part goes down. The stock springs are designed to counteract this based on spring rate, spring thickness, position, the surface area of the spring pad in the L direction, and distance between the centerline of the axle bore to the true center of the spring. All of these items have an effect and are generally calculated to conteract this.

When you start increasing the overall distance mentioned above, you are having an effect on the moment arm present. Meaning, the longer the distance, the less rotational force required to twist the leafs. Think of it using breaker bars. If I told you to take off a lug nut, but gave you to option to choose a 7” breaker bar or a 30” breaker bar. Which one would you choose? Obviously, the 30” because you gain mechanical leverage right? This same concept applies to blocks in a leaf suspension. The point where the leaf spring meets the block is your “socket” and the distance to the centerline of the axle tube, where the axle shaft is, is the mechanical leverage. The higher you go, the longer your breaker bar, the more leverage which equates to more axle wrap.

I even drew a picture, because I’m a nerd. The X measurement is the concern.

 

What do you have installed thats giving you a 4in lift? Im wanting to have mine at 4/2 as well

 

Thanks for the explanation! that definitely helps me understand this more. what are your thoughts on a 1.5" block though? I understand that larger blocks obviously contribute to axel wrap as explained in your post, but from I've heard from a number of offroad shops that specialize in Toyotas, this is really a non issue for 1-1.5" blocks.

 

No blocks, period. Regardless of the size, you are increasing that leverage point. Which then increases the forces to negatively arch that spring, since the surface area used to prevent the axle wrap is eliminated and the forces are greater acting upon that spring.

Blocks are just a cheap way to get lift, the proper way will always be longer leafs or shackles. Can you get away with it? Sure. Is it the right thing to do? Nope. Blocks on leaf springs are no different than the spacer lifts that people on here recommend against. It’s effectively the same concept, except that the spacer lifts have a negative connotation and blocks are a bit more “accepted”.

 

Had 1" blocks, came on the truck from previous owner. Replaced with a Tuff Country AAL and did Zone rear shocks at the same time. Back of the truck is firm-errrr, but I prefer that. It is by no means stiff, rough, or unbearable. The AAL provided about 1.5" of lift, I also prefer that for when I tow or carry a load in the bed, which is fairly often. I don't like blocks and will not use them by choice. The AAL is just a little more expensive than a cheap block, and less money than a machined aluminum block.

Blocks have a lot of negatives which have already been well documented in the previous posts.

AAL's have gotten a reputation as being too stiff. This is a story that has been passed down by truck owners that have never even used an AAL, "I've heard add-a-leafs are stiff and ride like crap". I personally have not noticed adverse driving characteristics using AAL's. I've had them on multiple vehicles in the last 15 years. I do tend to carry 100-500lbs in the bed more often than I have an empty bed. Are they stiffer than stock? Sure...It is rougher than an Escalade, but plusher than an F350.

Front end is toytec/eibach coilovers, 3". This front and rear setup gives the truck the slightest bit of rake. Most would say it's level, but my eyes notice it, and my tape measure from axle to fender says the same.

I too had the DS lean. I corrected this with 2 Coach Builder shims on top of my DS coilover.

I like shackles as a rear lift option as well. I just prefer the benefit of AAL's when it comes to load carrying capabilities and squat-resistance.

 

May be a stupid question. If the middle is the 1.5", which hole is the 1" setting?