How much weight to add-on for an AHC?

[stridertexas]

Thanks for the link LandCruiserPhil

While reading it, I found this post by TeCKis300. I feel like this has explained what I'd need to do to get my AHC roughly back to spec to handle off-road height with the added weight of a bumper, rack, and sliders.

I assume adding "air lift" bags would be in addition to this to help with heaving towing, should the need arise.

Thoughts? Have I reached the solution to my original question?

^

In general, I'd say it's good to throw in spacers as that will bring back some of the constant height capability due to the suspensions mechanical springs age (imagine those non AHC trucks that have the same age issue dragging their rear ends now). 30mm spacer rear. And 3.5x turns to each front torsion bar to bring it completely back into spec. So instead of 1000lbs of constant height capability, it will have 1300lbs of constant height performance (again, ballpark) If you want more, there are upgrade springs and/or airbags for more.

~5600lbs and 850lbs tongue. Tows beautifully. I have it in 'L' in this picture for my kids to get out, but it never dropped to L when I didn't want it to.
View attachment 1199266

 

[PADDO]

@uHu nailed the issues at post #14 - it's all about your pressures and damping globe charges. Permanently adding 500lbs is nothing really, you just need to ensure your neutral pressures are optimized for the ride height and weight you select. To understand where you want to be you'll need to understand where your system is at presently, in terms of pressures@height and the health of your dampers (remaining charge). Front pressures are easily managed. With your rear, if your current DD pressure is in the order of 7.2 or so (very common if still on original coils), then you'll want to get that down around 5MPa before adding the 500lbs. KTRS 79 coils are designed for this and without spacers you should realize an unladen pressure in the order of 5MPa. After adding your 500lbs you should be in the 6MPa range which is where you want to be for the rears for optimum damping and full design weight capacity. With new AHC coils and 30mm spacers you might get down around 6MPa, permanently adding 500lbs will take you to the upper point of the 5.6-6-7MPa damping range, maybe a little over. Your ride quality should be acceptable, but not optimum, and full load capacity not impacted too much. Good damping and maintaining ride height at N when loaded all comes down to optimizing front and rear pressures for your particular weight distribution and having damper globes that return 9+ graduations after pressures have been optimized. If you choose to add some sensor lift then understand there is an associated pressures penalty that adds to the mix too. Without knowing your pressures any attempt to optimize the system is just a WAG.

 

[stridertexas]

@uHu nailed the issues at post #14 - it's all about your pressures and damping globe charges. Permanently adding 500lbs is nothing really, you just need to ensure your neutral pressures are optimized for the ride height and weight you select. To understand where you want to be you'll need to understand where your system is at presently, in terms of pressures@height and the health of your dampers (remaining charge). Front pressures are easily managed. With your rear, if your current DD pressure is in the order of 7.2 or so (very common if still on original coils), then you'll want to get that down around 5MPa before adding the 500lbs. KTRS 79 coils are designed for this and without spacers you should realize an unladen pressure in the order of 5MPa. After adding your 500lbs you should be in the 6MPa range which is where you want to be for the rears for optimum damping and full design weight capacity. With new AHC coils and 30mm spacers you might get down around 6MPa, permanently adding 500lbs will take you to the upper point of the 5.6-6-7MPa damping range, maybe a little over. Your ride quality should be acceptable, but not optimum, and full load capacity not impacted too much. Good damping and maintaining ride height at N when loaded all comes down to optimizing front and rear pressures for your particular weight distribution and having damper globes that return 9+ graduations after pressures have been optimized. If you choose to add some sensor lift then understand there is an associated pressures penalty that adds to the mix too. Without knowing your pressures any attempt to optimize the system is just a WAG.

Thanks for the info, I re-read #14 and understand now what to do