AHC Height Offset Utility How-To (1 Viewer)

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Not sure how I missed this thread. Great "stuff" here on how to fit biiig tires. This 305/70r18 is on the big end for sure, measuring out at 34.8" x 12.2". Great to see that fitment work which is a larger overall diameter tire than a classic inch sized "35 x 12.5", typically measuring out to 34.5" x 12.5".

@radman , how's fitment working out so far? Looks like you didn't even need a body mount chop (BMC) to fit these. I'm entertaining a 35x12.5 which I know will fit without too much trouble per your guide above. Or a 325/60r20 (35.4" x 13"), which might just push things too far and need more work - BMC, 3/8" body lift, etc. It would be a fun project.

Tires really are the ultimate lift and suspension upgrade off road and I think it might be worth the effort. They keep the diff high, and aired down they do so much of the work to flatten out the road.

Regardless, I'm wanting gears too and I think 4.3 will do the trick for any of these.
 
This 305/70r18 is on the big end for sure, measuring out at 34.8" x 12.2". Great to see that fitment work which is a larger overall diameter tire than a classic inch sized "35 x 12.5", typically measuring out to 34.5" x 12.5".

I went with the 305/70/18 because I thought it would be a little smaller than the classic 35x12.5 :rofl:
Weighted width of the 305 is at 34.5".

So far, no rubbing in Normal or High modes, but I haven't checked a big flex yet. I can pull a full u-turn in low mode as long as its flat; however, if i try to turn up my driveway in Lo, it will rub the liner in front of the pinch weld.



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In case you need some more height, I made some simple aluminum brackets in the front to adjust the sensors more.

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Would love to get someone to explain this to me because I can't tell from the picture what's going on.
 
What are you doing about a spare? There are other folks here running 285/75/18 but that size will not fit under the truck.
Spare is currently up top, but patiently trying to wait for my Dissent bumpers to arrive.

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Would love to get someone to explain this to me because I can't tell from the picture what's going on.

He rigged up an aluminum bracket to "extend" the sensor arm and gain more lift.
 
@Prime - how much lift do you have at the normal position now? Can you measure front and rear hub to fender?

Wonder if high position is still useful?
 
Would love to get someone to explain this to me because I can't tell from the picture what's going on.

@Prime - how much lift do you have at the normal position now? Can you measure front and rear hub to fender?

Wonder if high position is still useful?

These pictures should help.The bracket just moves the sensor “down” to extend the range of adjustment. Basically this gives high suspension level without the 20mph cutoff. I did something similar in the rear but drilled holes higher in the bracket to mount the sensor. I’ve put 5k+ miles on this with no major issues. Rear also has no sway bar.

High setting still functions fine but won’t always change the display on the dash from N to H. Ride is kinda rough in H but I have strut spacers to add at some point soon to relieve the pressure.

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Great write-up Radman. I am curious. Did you do or will you do a gear change once you got those 35s on?
 
Great write-up Radman. I am curious. Did you do or will you do a gear change once you got those 35s on?

Stock gears with the 6-speed! I'm happy with the drive, but maybe it's because I don't know what 4.88 feels like. I'm pretty sure @Prime is running stock as well. We'll see what 250 additional pounds of bumper does for me.
 
I opted to start with the gear change so that as I modded I could just add whatever I wanted without having to worry about incremental performance loss.

Doing it later when you think you need it is also totally viable. You might decide it's fine, and never do it. Or you might begin to hate your rig and not know why when you gradually cross the whatever it is to you performance threshold.
 
These pictures should help.The bracket just moves the sensor “down” to extend the range of adjustment. Basically this gives high suspension level without the 20mph cutoff. I did something similar in the rear but drilled holes higher in the bracket to mount the sensor. I’ve put 5k+ miles on this with no major issues. Rear also has no sway bar.

High setting still functions fine but won’t always change the display on the dash from N to H. Ride is kinda rough in H but I have strut spacers to add at some point soon to relieve the pressure.

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Ah okay - the two bottom bolts are just holding the aluminum stock to the bracket, the top bolt sets the position of the sensor.

Would gladly Venmo someone some cash for a set of these to try. I don't have the tools to make a set and fiddle with the measurements.
 
^You can do it! I've seen the things you've built, and this is well within your abilities.

Looks like a piece of aluminum flat bar stock that is easily available at any hardware store. @Prime can tell us, but it looks like .75" width stock. .5" may work too.

Aluminum is soft and easy to work with wood working tools. Throw it in a vice and cut to length with a hacksaw, jigsaw, dremel, whatever. Many things can work, though AL tends to load up fine blades and abrasives type bits. You're not cutting enough for it to probably matter.

Drill with any bit. Stepped metal bits work great. Few holes and few bolts will do it.g

That said, I'd temper the want to do it this way. Physical sensor lifts can do ~1.5". Software height offset, another .8". For a total of 2.25". I think that's about the limit to making sure AHC high position (+3") is actually still functional without pegging out the suspension and maintaining some meaningful droop for articulation.

Combining 3" + 2.25" is a 5"+ lift.

Add some 35s for ~2" tire lift. 7"+ lift!
 
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Physical sensor lifts can do ~1.5". Software height offset, another .8". For a total of 2.25".

So this is how I'm setup now, and I've been wondering how much more the shocks can handle. Prime's setup takes it to a whole 'nutha level. Curious about his droop and flexing.


(Actually, I would say the physical sensor is closer to a 1" and the AHC is realistically .5-.75" by the time you use it to level out. )

1.5" tire lift, 1" sensor lift, .5" AHC lift puts me 3" above stock (in normal mode).


Looks like a piece of aluminum flat bar stock that is easily available at any hardware store. @Prime can tell us, but it looks like .75" width stock. .5" may work too.

It looks like the top 2 bolts are into the stock bracket and the bottom is the arm.

I'd do 2 bolts with a piece of aluminum half the size he has. This would allow some movement; the way it's pictured looked fixed.

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I'm curious what others measurements are.

I did a mild sensor lift with mine - .75" front and .5" rear, as I strongly believe less is more at times. In my experience off-roading, even this mild lift provide prodigious clearance when paired with 33.2" tires and AHC high. I have an OEM front strut spacer with mine to increase front end droop travel and articulation.

Copied from here, these are my measurements:

Measurements from center of hub to fender (suspension lift):
Front (lift)Rear (lift)
Stock AHC "N"19"20.75"
Stock AHC "H"21.0" (2")23.125" (2.375")
Sensor Lifted AHC "N"19.75" (0.75")21.25" (0.5")
Sensor Lifted AHC "H"21.75" (2.75")23.625" (2.875")
Sensor Lifted AHC "Extra High" (projected)22.5" (3.5")24.375" (3.625")

Measurements from ground to fender (suspension and tire lift, w/ 305/55/20 33.2" tires):
Front (lift)Rear (lift)
Stock AHC "N"34.5" (1")36.125" (1")
Stock AHC "H"36.5" (3")38.5" (3.375")
Sensor Lifted AHC "H"37.25" (3.75")39" (3.875")
Sensor Lifted AHC "Extra High" (projected)38.0" (4.5")39.75" (4.625")
 
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I've got my sensor lift maxed out. I think I want squeeze out a little more lift either by using the Techstream AHC utility or by making a bracket to extend the sensor adjustment. I'm wondering which method would be better for the vehicle as far as keeping the suspension within it's operating envelope.
 
I'm curious what others measurements are.

Measurements from ground to fender (suspension and tire lift, w/ 305/55/20 33.2" tires):
Front (lift)Rear (lift)
Stock AHC "N"34.5" (1")36.125" (1")
Stock AHC "H"36.5" (3")38.5" (3.375")
Sensor Lifted AHC "H"37.25" (3.75")39" (3.875")
Sensor Lifted AHC "Extra High" (projected)38.0" (4.5")39.75" (4.625")


I'm at 37.75" ground to fender (fronts) in "N" and 39.25" in High mode. I don't think I've ever seen "extra high" mode, but that would put me at 40". I haven't taken the time to test, but I think you have to be in 4Lo AND have a wheel spinning freely. Or is your understanding that 4Lo automatically raises you to extra high?
 
I've got my sensor lift maxed out. I think I want squeeze out a little more lift either by using the Techstream AHC utility or by making a bracket to extend the sensor adjustment. I'm wondering which method would be better for the vehicle as far as keeping the suspension within it's operating envelope.

Same difference! AHC is limited to .8" and will look "more stock" if you ever go into a dealer, but please don't😂
 
I'm at 37.75" ground to fender (fronts) in "N" and 39.25" in High mode. I don't think I've ever seen "extra high" mode, but that would put me at 40". I haven't taken the time to test, but I think you have to be in 4Lo AND have a wheel spinning freely. Or is your understanding that 4Lo automatically raises you to extra high?

40"+ to the fenders is in rarefied air for the 200-series. That's up there. Interested in @Prime 's numbers.

Yes. I was off-roading this past weekend and did a large hill climb that involved some slipping. Should have busted out the tape measure to check. I'm always in low-range off-road as it helps the torque converter, tranny, and engine, keeping everything cool. AHC seems to jack up notably higher this way and I'm almost ever wanting for clearance. Except for the pumpkin which is why I'm such a proponent of big tires.

At the same time, making sure I keep some droop and articulation when in high mode is important so I don't particularly have a want to jack normal position up too high to keep high mode more useful. I believe the front OEM shock spacer really helps in this regard to improve front suspension travel and droop.

I should keep a tape measure on board.
 
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Interested in @Prime 's numbers.

that dude just cut up his fenders... no way to measure anymore! :rofl:

@TeCKis300, how are you accurately measuring "center of hub"? top of center cap to fender is an easy way to compare the 4 corners.
Also, wouldn't an OEM spacer limit droop more? seems like we need to figure out the full stroke of the shock and work our way backwards.
 
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