2-2.5" AHC Lift Using King Coils & Shock Spacers

[krispykritter]

@DJCloz mentioned to me that the King coils probably wouldn't work on my truck with it loaded down heavy plus with all of the armor and in conjunction with an AHC lift. He suggested standard coils instead. Has anyone gone this route with a heavy/lifted AHC system? I've heard of people using 80 series coils, but not regular 100 series with AHC, so I'd love to hear more feedback along those lines if anyone has it.

The other thing that's been bouncing around my head is the possibility of using the Kings with spacers and airbags only for when it's loaded down. I've never used airbags before, so the idea of depending on them scares me a little.

I have heard of this being done before with heavy builds. It's on my list of things to do once I get a rear bumper/tire carrier. Personally, I don't care about being able to put the truck in hi mode, I care about the auto-load leveling as I tow an offroad trailer on most trips with me.

Let me see if I can find a thread with some one who went to non-ahc coils for their build...

Here's one but not the one I was looking for: Anyone running 100 series springs and shocks on a AHC system with armor? - https://forum.ih8mud.com/threads/anyone-running-100-series-springs-and-shocks-on-a-ahc-system-with-armor.1065943/

 

[xplore]

I have heard of this being done before with heavy builds. It's on my list of things to do once I get a rear bumper/tire carrier. Personally, I don't care about being able to put the truck in hi mode, I care about the auto-load leveling as I tow an offroad trailer on most trips with me.

Let me see if I can find a thread with some one who went to non-ahc coils for their build...

Here's one but not the one I was looking for: Anyone running 100 series springs and shocks on a AHC system with armor? - https://forum.ih8mud.com/threads/anyone-running-100-series-springs-and-shocks-on-a-ahc-system-with-armor.1065943/

Thanks for pointing out that thread! There are so many different AHC modification threads that it's hard to keep track of where you read something before. I agree with you that height is not the priority, although, it would be nice to be able to give it a slight sensor lift and to still have full functionality when loaded down. I would consider that a luxury, but the primary goal is just to keep the system in a healthy pressure range when loaded or towing while retaining the auto-load leveling.

I've seen these spring rate comparisons below in several threads including the one you just linked, so I thought the 80 series coils would be the best bet rather than going all the way to the standard 100 series coils... Although, I have seen some people say that the 80 and 100 series rear coils have the same spring rate, so it's hard to know what to believe. At the end of the day, you just have to be willing to do a little trial and error based on your best estimates when you're coloring outside the lines on a project like this.

470 AHC spring rate = 95 lbs/in
King = 130
450 = 150
100 = 170

Along with some of the spring rates mentioned, and with @Sargy's feedback from the threads below, I just broke down and bought the Dobinsons C59-221V coils. It sounds like those will get me really close to what I want, and I'll consider incorporating coil spacers or airbags if I need a little more weight capacity.

2-2.5" AHC Lift Using King Coils & Shock Spacers

Awesome - thanks Dawg & Hoser. Exactly the info I was looking for. Any idea about availability of those spacers? Is the guy in Japan still around?

forum.ih8mud.com

Coil springs for AHC

forum.ih8mud.com

 

[krispykritter]

I might have to go to that sort of setup eventually. I'd rather not have the spacers but the kings + spacers have done well so far. I believe the 80 series springs are longer so that might be ideal. Too stiff for me right now but with extra weight hanging off the back it's probably perfect. Would appreciate your feedback once you get it all installed.

 

[xplore]

I might have to go to that sort of setup eventually. I'd rather not have the spacers but the kings + spacers have done well so far. I believe the 80 series springs are longer so that might be ideal. Too stiff for me right now but with extra weight hanging off the back it's probably perfect. Would appreciate your feedback once you get it all installed.

I'll definitely report back on my findings. Like you mentioned earlier, there could be a risk of losing a coil depending on the suspension articulation when using those shock spacers, so I really like the idea of the longer 80 series coils.

 

[augustwest]

I'm with you guys on going with a spring only and avoiding the spacer if possible. The 80 spring is intriguing and I'll be interested to see how it works with your setup.

I'll have a rear bumper with swingouts, sliders, RTT, and drawers/fridge loaded up in the back, so I'm going to have to figure something out soon.

 

[xplore]

I just broke down and bought the Dobinsons C59-221V coils. It sounds like those will get me really close to what I want, and I'll consider incorporating coil spacers or airbags if I need a little more weight capacity.

I had a little bit of a change of plan. The website I purchased the Dobinsons springs from said that they're actually not in stock, and apparently no one has them anywhere right now. Vivid Racing said they expected to have some back in stock by January, but I don't want to wait that long, and who knows if they'll even have them by then. I just picked up a set of take-off 80 series coils, so I'm going to use those in conjunction with some Firestone Coil-Rite bags, and that should do the trick.

 

[augustwest]

I'm with you guys on going with a spring only and avoiding the spacer if possible. The 80 spring is intriguing and I'll be interested to see how it works with your setup.

I'll have a rear bumper with swingouts, sliders, RTT, and drawers/fridge loaded up in the back, so I'm going to have to figure something out soon.

Got a rear bumper arriving later this week and hope to install it over the weekend. I wasn't anticipated having a rear bumper this quickly due to the insane lead times, but I stumbled into one from 4x4labs so my timeline for sourcing some King KTRS-79 springs has accelerated considerably. I saw someone suggest emailing Nick at Fulcrum Suspensions, as he sourced and shipped them some in relatively short order. I emailed him a couple days ago but have yet to hear back. I'm hoping to go this route, but does anyone know of any other reliable ways to source these springs?

 

[suprarx7nut]

Got a rear bumper arriving later this week and hope to install it over the weekend. I wasn't anticipated having a rear bumper this quickly due to the insane lead times, but I stumbled into one from 4x4labs so my timeline for sourcing some King KTRS-79 springs has accelerated considerably. I saw someone suggest emailing Nick at Fulcrum Suspensions, as he sourced and shipped them some in relatively short order. I emailed him a couple days ago but have yet to hear back. I'm hoping to go this route, but does anyone know of any other reliable ways to source these springs?

tried ebay yet?

 

[krispykritter]

I think I ordered mine off of ebay a few years ago. No idea if there's any available now.

tried ebay yet?

lol what he said!

In other news, I've sourced a set of OEM, non-AHC torsion bars. I'm getting rather sick of my insane bumpsteer issue, so I'm going to experiment a bit with using AHC and thicker sway bars. Plan is to crank my t-bar adjusters all the way down (minimum preload), install the heavier bars, then add just enough back in to get my front end in spec at ride height and see what that does to my carolina-squat-on-acceleration problem.

Theory is, stiffer bars won't need nearly as much preload to hold the weight of the truck, but will unload much faster as the suspension droops when I stomp the gas. That should mean they stop contributing to the front end lift much quicker than the AHC bars. What I don't know is how the AHC will react to having the heavier bars in there. I've gotta think it'll be similar to how the rear behaves with 40% stiffer springs, which is fine. Figure the worst case is the new springs are a bit underdamped, which I can probably live with. I'm just not sure how it'll feel in compression, as I really like the cushy ride I have now.

BTW I weighed my lexus at the dump the other day, and with me and a dead microwave in it, it's at 6300 lbs.

 

[augustwest]

tried ebay yet?

There is one listing on there for ~$180 with $115 shipping. Puts them at ~$295 shipped. Seems a bit high but I suppose beggars can’t be choosers.

 

[suprarx7nut]

There is one listing on there for ~$180 with $115 shipping. Puts them at ~$295 shipped. Seems a bit high but I suppose beggars can’t be choosers.

Sounds typical. I think mine were $250-280 a year ago.

 

[augustwest]

Sounds typical. I think mine were $250-280 a year ago.

Ok, I might just go that route then.

 

[brauski]

Struggling to get the rear Japan 4x4 shock spacers on. Was doing it one side at a time, will try lowering the whole axle equally next.

Anybody else have any difficulty? Maybe loosening the nut at the top of the shock could help?

 

[krispykritter]

Struggling to get the rear Japan 4x4 shock spacers on. Was doing it one side at a time, will try lowering the whole axle equally next.

Anybody else have any difficulty? Maybe loosening the nut at the top of the shock could help?

If you're having issues getting them on, you can relieve some pressure from the shocks by opening the bleeders and letting some fluid out. You'll need ot have more on hand to replenish when you're done. Also, keep in mind, the stock brake line isn't long enough to accommodate full droop of the axle with both wheels off the ground without bending the mount points or buying new longer lines. Also, your sway bar will hit your shocks at full droop as well. Longer end links take care of that problem.

Whenever I've messed with the whole rear axle, I was lucky enough to have a lift to put the lexus on. I haven't tried doing this job in the driveway on jack stands.

 

[krispykritter]

Sorry - double post

 

[suprarx7nut]

Struggling to get the rear Japan 4x4 shock spacers on. Was doing it one side at a time, will try lowering the whole axle equally next.

Anybody else have any difficulty? Maybe loosening the nut at the top of the shock could help?

If you're having issues getting them on, you can relieve some pressure from the shocks by opening the bleeders and letting some fluid out. You'll need ot have more on hand to replenish when you're done. Also, keep in mind, the stock brake line isn't long enough to accommodate full droop of the axle with both wheels off the ground without bending the mount points or buying new longer lines. Also, your sway bar will hit your shocks at full droop as well. Longer end links take care of that problem.

Whenever I've messed with the whole rear axle, I was lucky enough to have a lift to put the lexus on. I haven't tried doing this job in the driveway on jack stands.

Yup, my thoughts were similar. Check brake lines, sway bars. If you bleed any AHC pressure, take extreme caution. You can shift weight quickly and that can turn deadly if you're using precariously placed jackstands.

 

[LostInMyLX]

Great write up! I’ll be doing this ASAP!

 

[krispykritter]

@suprarx7nut do you run aftermarket UCAs? I've ordered a set of the new nitro arms so I'll probably throw those on first and see if the extra caster helps with the pitchiness at all. If not, then I'll be putting in the non-AHC torsion bars and seeing what effect that has. I'm hoping I can get a bit more lift with good driving manners but I think the softness of the AHC suspension is what is causing my bad behavior.

 

[jtb517]

@suprarx7nut do you run aftermarket UCAs? I've ordered a set of the new nitro arms so I'll probably throw those on first and see if the extra caster helps with the pitchiness at all. If not, then I'll be putting in the non-AHC torsion bars and seeing what effect that has. I'm hoping I can get a bit more lift with good driving manners but I think the softness of the AHC suspension is what is causing my bad behavior.

Let us know how the nitro arms work out!
Thinking about going that route myself, but haven’t seen many reviews of the newest version of the nitro arms.

 

[krispykritter]

Let us know how the nitro arms work out!
Thinking about going that route myself, but haven’t seen many reviews of the newest version of the nitro arms.

Me neither. They look good and the price was right (a bit under $600 shipped). I'm going to cut my AHC sensor brackets off the old arms and tack them onto the Nitro arms when I do the install so the AHC stuff should work roughly the same, I hope.