King Springs AHC KTRS-79

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Ramathorn15

Ramathorn15

Joined
Jan 8, 2016
Threads
49
Messages
1,361
Location
ABQ NM
Hey all. There's a couple threads where these springs are mentioned but I wanted to give some details for people who are interested in them.

First off, I bought mine from "spares box" on eBay for a few dollars less than $200 USD with shipping. They took about 2 weeks to be delivered.

Installation is relatively straight forward. Just follow lift kit directions for replacing coils in a land cruiser. Just be careful because having a loose axle can spell trouble if it's not supported properly.

Anyway, here are my techstream/measurements before and after.

Stock Coils:

Front pressure: 6.9mpa
Rear pressure: 7.1mpa

King coils:

Front pressure: 6.7mpa
Rear pressure: 2.9mpa

The height didn't change and my LX is stock height. As you can see the kings dropped the rear pressure by 4.2mpa. I honestly did not expect it to be that much of a drop.

Now for the ride, it really didn't change the ride to drastically. From other threads mentioning using 80 series springs, I thought they were going to cause my rear to be bouncy due to no change in weight. Not the case. the rear rides nicely, but is definitely more firm. It not harsh though.

The adjustable dampening is nearly gone, but that's because coils are holding almost all the weight in the rear. Once it's loaded up with my bumper and other stuff, I presume it will come back.

I think the spring rate on these is better for our setup.

Btw, the coils measure as follows:

Total coils: 7
Height: 17"
Width of coil: 1/2"
Diameter: 7-3/4"
Diameter - 1width: 7-1/4"
 
Thanks for writing this up. I've got a spacer in the rear but I'm sure these would be much more suitable for anyone wanting to retain AHC long term. It makes me much more comfortable thinking about adding drawers and a rack knowing that if my numbers go up too much these are pretty affordable.
 
Give her a slight AHC sensor lift (1/4-1/2") all around. This will bring the rear AHC pressure up a tad to bring damping and ride back into the sweet spot. You'll want to crank the front torsions also to support the new front height.

That should be the ticket!
 
I've had these springs for about a year and agree that the ride is not harsh. When you load the truck up it rides very nicely and the AHC pressures don't rise beyond their max limits allowing the truck to rise to high with upwards of 600 lbs of people and gear. If you can find these I would highly recommend them.
 
Don't plan on lifting. I bought these with the intentions to wait until I had the dissent rear bumper, rack, and RTT but put them on prematurely to tow a motorcycle.

I'm going to wait until I have all the aftermarket weight added on, then readjust the pressures. If they're still too low with all the gear, I'll have to lift it some, but I'm hoping not to.
 
I'm very interested in this, I have close to 310k on my AHC and need to start preventative maintenance
 
With putting these in then lifting a little with the sensors would the rear still need 30mm spacers or would the stiffer spring suffice?
 
sailor95 said:
With putting these in then lifting a little with the sensors would the rear still need 30mm spacers or would the stiffer spring suffice?
Click to expand...

No need for spacers for an incremental lift. Though it all depends on how far you want to lift. Springs have a designed in height. At stock ride height, based on the data above, there's actually too much "spring" in the the setup. Springs are rated by weight per unit of deflection (or compression). So by doing an AHC lift, there would be less compression on the KING spring, hence it will support less of the overall rear weight, putting some load on the AHC system.

No one has definitively figure out what the ideal lift is to get at the stock neutral points of the AHC system. But it wouldn't be hard...just some trial and error.
 
Last edited:
sailor95 said:
With putting these in then lifting a little with the sensors would the rear still need 30mm spacers or would the stiffer spring suffice?
Click to expand...

With a reasonable lift 1-2" in the rear you should not need an additional 30mm of spacer with these springs. It would require some trial and error to get the correct height as this is all a balancing act. Throw a rear bumper, rack, sliders, and rtt along with standard camping cargo and you may need spacer along with those springs on a lifted rig.
 
I wish I could afford all the extras to go along with it. I'm just hoping to prolong the life of my AHC with some better springs, hopefully gaining an inch or so of lift and retaining load capacity.
 
Recognize that the KING springs also have higher spring rate. So in addition to it bearing more weight, it will support the load without as much deflection.

It's a distinction between a load bearing setup and a good articulation setup. If the car does not have a lot more weight on it with bumpers, gear, etc... a higher spring rate setup will actually hurt off road articulation, hence performance. But good for on road road handling.
 
Ramathorn15 said:
Hey all. There's a couple threads where these springs are mentioned but I wanted to give some details for people who are interested in them.

First off, I bought mine from "spares box" on eBay for a few dollars less than $200 USD with shipping. They took about 2 weeks to be delivered.

Installation is relatively straight forward. Just follow lift kit directions for replacing coils in a land cruiser. Just be careful because having a loose axle can spell trouble if it's not supported properly.

Anyway, here are my techstream/measurements before and after.

Stock Coils:

Front pressure: 6.9mpa
Rear pressure: 7.1mpa

King coils:

Front pressure: 6.7mpa
Rear pressure: 2.9mpa

The height didn't change and my LX is stock height. As you can see the kings dropped the rear pressure by 4.2mpa. I honestly did not expect it to be that much of a drop.

Now for the ride, it really didn't change the ride to drastically. From other threads mentioning using 80 series springs, I thought they were going to cause my rear to be bouncy due to no change in weight. Not the case. the rear rides nicely, but is definitely more firm. It not harsh though.

The adjustable dampening is nearly gone, but that's because coils are holding almost all the weight in the rear. Once it's loaded up with my bumper and other stuff, I presume it will come back.

I think the spring rate on these is better for our setup.

Btw, the coils measure as follows:

Total coils: 7
Height: 17"
Width of coil: 1/2"
Diameter: 7-3/4"
Diameter - 1width: 7-1/4"
Click to expand...


Am I correct that the specs for AHC pressure in the rear is 5.6 to 6.7 Mpa? In which case you went from out of spec, High to out of spec, Low with these?
 
Ramathorn15 said:
Don't plan on lifting. I bought these with the intentions to wait until I had the dissent rear bumper, rack, and RTT but put them on prematurely to tow a motorcycle.

I'm going to wait until I have all the aftermarket weight added on, then readjust the pressures. If they're still too low with all the gear, I'll have to lift it some, but I'm hoping not to.
Click to expand...

Got it, that makes sense. I have added a rear bumper from BIO, but have not checked pressures since then.
 
I forgot to take a pressure reading during HIH when the truck was loaded up with the RTT, rack, drawers, and supplies. It did feel really good on and off road and went into H easily as well. I suspect once I have the Dissent bumper, rack, and drawers, I will be really close to stock rear pressures unloaded. Then with the RTT and gear, I may have a slight overpressure. Lifting it would obviously shift that further away.
 
DirtDawg said:
Mine just came in a couple days ago. Waiting to get my Techstream stuff in then I'll report.
Click to expand...

Please do report back with your findings. It will be most helpful to those of us contemplating the same thing.
 
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