King shocks riding incredibly firm after shackle install

So there's two separate issues here.
First, even with a 3/4" shackle, the OE Kings will bottom out before the suspension will. Meaning if the rear end suspension drops out fast enough, the shock will be the suspension limiter. This is why King stated you are outside of the operating range for their shocks.

Second, the reason the ride changed is absolutely a result of the shackles. Shackle lifts are a cheap fix, but they beget other problems. The longer the shackle, the more you will preload the leaf pack and decrease payload. As the lever increases (shackle is the lever), the ride height changes but also pushes the ends of the leafpack out laterally (making the pack straighter/flatter at ride height) which in tern preloads the leaf pack. Because the pack is more loaded when compared to a stock length shackle, the perceived ride inside the cab is "stiff" or "bumpy" and is exacerbated by the fact that the leaf pack has a progressive spring rate. T'is an absolute result. Shackle lifts suck other than to lift the rear of the truck higher.

Now that said, there are some valving tricks you can do to make it play nice together. I did a few revalves on mine and am completely happy with how mine is performing now. For reference, I have the OE Kings (without clickers) and added the Total Chaos 3/4" lift shackles. Here is my final valving.

Compression
175-.010
160-.010
100-.008
145-.012
130-.012
115-.012
100-.012
Rebound
.010 full stack

Nitrogen charged to 160 psi


Also for reference, @jlee has basically my same setup with no issues either. Shackle lifts suck man. Sorry to say it.

 

Honestly, IMO 700# coil spring is way too much for a stock 2nd/3rd gen tundra. If you have a plate bumper and possibly a winch, sure, 700# is the way to go. But the effective angle on the coilovers is damn near perfect. I run the 600# spring on mine, and that's with the added weight of the supercharger. IMO too many people are obsessed with ride height. The reality is you're not going to clear any larger of a tire with more front lift (separate from a drop bracket lift) than you will with a stock truck. The suspension still moves up and down, parked ride height is only one position. The truck itself will set ride height. Try to overcome that and you'll end up playing games like you are now with trying to add more rear lift which in turn fucks with the valving and custom shock lengths and blah blah blah. My truck is sitting on only 2.75" of front lift, the 3/4" shackles on the rear, and 35/12.50/18's and it looks and rides tits.

If it were me...I would suggest mirroring my setup. But everyone has their own individual wants. To some aesthetics is more important than ride quality. I'm not one of them.

T'is = It is. T'is the season to be jolly........

I have the TRD sway bar on mine. Just saying.

 

King is trying to give you a cheap fix. The lowest you can go with one of their IFP shock (non-emulsion) is 90 psi. But nitrogen psi is not a substitute for valving. Valve for operating PSI (150) and micro changes to the nitrogen for additional fine tuning.

 

I learned some tech today....never messed with shackles on a vehicle until the Tundra.

I went down the coach builder shackles money train, and even with the 5160's in the rear I didn't feel the ride was improved.

 

Did you install the new bushings with the shackles?

 

700#'s on the front is good then given the bumper and winch. I wouldn't go custom shocks given your setup (personally). You've got a hell of a good foundation. Given your aesthetic requirements (limited rake), I would remove some preload out of your coilovers and go with a 3/4" or the Coachbuilder .625" shackles. You won't have as much lift, but I bet the ride will be significantly better. At the end of the day, ride height is mostly about aesthetics. Yes there are some differences if you are building a crawler, but nobody is going to make a crawler out of a 2015 Tundra. 1/2" of preload isn't going to be the difference of you making it out to your backwoods over logging roads.
If it's still too stiff, I would take King up on the revalve. Given you have clickers, they typically valve those lighter on the compression side such that the middle of the clicking range would be equivalent to what I have now. If you want softer, you can lower it, if you want stiffer, you can increase it. When they revalve, they will recharge it at their default 150.

All the suggestions you've got so far are lip stick on a pig. Cheap/easy ways to try to make what you have work. Especially the bit about dropping the nitrogen pressure. You really want a good nitrogen charge in the nitrogen cavity. It helps push the IFP back on rebound and prevents the shock from hydrolocking.

The compression valving I have in my shocks are what's known as a flutter stack. It allows for a very plush ride over slow shaft speed movements (around town, speed bumps, curbs, kittens, priuses), but the mid/high speed shims I upped the valving so it can handle bigger hits/mild whoops/wash at medium speed without blowing all the way through the shock. You'll notice that the 145-100 shims are all thicker than the 175 and 160 shims. The 100 shim in between is the flutter shim that allows the slow speed shims to flex easier. I also ran a full 10 stack on rebound mostly in part because of the unsprung weight of the rear end. I run 35" tires which are a lot heavier than the stock ones. The thing is with valving...there is no out of the box answer. Everyone has different preferences on ride characteristics and different suspension setups, different weight they carry (full sized spare, plate bumpers, RTTs, spare fuel, water, etc.). All this shit comes into account. IMO there is no such thing as out of the box. Valving should always be tuned to the driver and the vehicle. This is why every one of my vehicles that I tune, I weigh the truck on a scale that has separate pads for front/rear weight and calculate unsprung weight based on whatever additions I have (big brake kits, wheels, tires, etc.). From there it's trial and error for MY preferences. Keep in mind you have clickers. They reduce the shock oil flow through the adjuster orifice into the resi. This is kind of a cheater method to add/remove some compression damping without having to revalve or a bypass. Meaning you likely won't have exactly the same valving that I have.

King also has a phenomenal tuning department. But help them help you. The more information you can give them, the better response you will get. As an example, I've pasted an email below I sent to them (way back in the day before I knew anything about shock tuning). They gave me an excellent starting point which would probably be fine for 95% of the people out there. I'm OCD as fuck and expect a lot out of my suspension. If it's not exactly how I want it, I try again.

Blah blah...tl;dr. At the end of the day I'm just one asshole on the internet. My advise is based on my preferences, my opinions, and my experiences. And you know what they say about opinions. Good luck to ya bud.


Sample email to king tuning: tuning@kingshocks.com

 

One other note @irishpride114. At least you have the balls to admit when you purchase something and it doesn't meet your expectations. At this day in internet age, too many people are stubborn to justify shitty purchases, despite fact vs. fiction, and will argue it all day long. It's not rocket science, but it is science. I by no means claim to be a suspension genius. I'm not the one building the shocks or a-arms, but I know the difference between a well tuned/proper geometry suspension and out of the box whatever. I'm the asshole that cycles my suspension, measures for bump steer, and tunes to my liking. And if something sucks...I'm the first to admit it, regardless of how much money I spent.

 

If you are an ADS man, for the love of god please talk with Matt at MCM. He's got a titties Deaver leaf pack (K37) and custom shackles and ADS bypasses that fit the factory mounts. If my truck wasn't a tow pig, that's what I would have.

 

Define "occasionally" and how much weight.

 

That's nothing. Go with MCM.

 

Yes, and MCM's shackle. You'll flex the pack up and down slightly better and his bypasses are designed for it.

 

I'm not getting how 1/4" lift height difference on the rear will change the suspension so drastically. I get that it will be rougher if your fully compressing the shock to its internal bumps at 1" and not at 3/4" but I don't think that is what is going on here.
Extremely stiff ride in the rear to me means that the rear isn't cycling like it should. Just not seeing the 1/4" being the problem there.

I have had my rear shackles set at 1.5" and dropped down to 1". Same feel between the two heights. Not too stiff. Not a major difference from the 1" block I had before either.