BFG KO2 265/65 18 PSI?

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avslash

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@jwest

What size tires are you currently running? I know you have mentioned it here or at portal, but I don't recall.

I'm starting to think about my next set, and I'm considering ordering one 34ish to see if there is any possibility of making it work on the LR4 with the Compo wheels.

If I recall your setup correctly, you are on 34's, with Compo wheels, Proud Rhino strut spacers, some thickness of wheel spacers and a "rod lift" full time?

You are spot on about the weight. My LR4 weights within about 500 pounds of my diesel F250.

To comment on the thread topic, on the streets I run my KM2's at the max cold pressure indicated on the sidewall; 80 psi. I knock them down to 50ish when off pavement. I don't really do any sand, but would knock them down further if I did.
 
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jwest

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If I recall your setup correctly

Sorry but much of that *is incorrect. Factory 18’s, no wheel spacer, shorter rod ONLY to keep computer seeing things in its happy range( they are not over correcting to add height)

So, the strut spacer adds 2” to the distance from bottom mount in LCA to top of strut mount hat. My intention and current setting is to have the air strut at its same extension as during stock use. This means the strut is not extended not compressed. However, due to the top strut spacer the axle and hub etc are all dropped by roughly 2”.

Then I used the IIDtool to set the hub center to fender distance to factory + 50mm. Upon writing this I realize I did not account for the geometries occurring around the difference between lca pivot vs strut vs hub. 2” at the hub does equal 2” at the strut unless they got some good parallelogram geometry built in there.

Amyway, hub to fender is at 50mm more.
Regarding the tires, a spacervwoild fender this 100% impossible and I tried that with the less common 25mm wheel spacer. Massive rubbing all over: against the slider, the front bumper, terrible compression issues at upper front bumper and fender flares. Also at the rear it then runs into the wheel arch under compression. Spacers are a killer on these vehicles. Even the compo (10mm right) would screw it up too much for my preference.

I need you to also understand my inner fender spaces are fully modified to remove all bulges and such.

These tires will not work without the strut spacer because under compression you grind the hell out of the fender flares as well as inside the body arch itself. Any loss of air suspension and you would be literally stuck, not just annoying worried stuck, but honestly unable to go as 30% of tire would be jammed into the body arch.

The best worry free size is 32” 275/65-18 but you could experiment with 33” 275/70. Just don’t be a dork and skimp on the necessary physical modifications of cutting and routing things. Remember, rods aren’t a ‘mod’, they add nothing whatsoever.
 
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todd jackson

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was that sarcasm? .... road psi you cannot really simply ask what people use unless you know their vehicle weight. a stock lr3/4 with an E load 265/65-18 is probably barely ok using 42psi but a factory tire and size is fine at 42. If you have weight on it, like mine, you'd be advised to use NO LESS than 52-4 psi.

However, offroad is not so simple either. The 'squish' factor in the same size tire on mine vs a stock lr3 will be very different because mine weighs over 7000 lbs, always, and with the rack and RTT plus full fridge and another person, and both tanks fully fueled, it's over 8000.

I am now using 22 psi BUT that's in a tire designed for it AND they are 34" tires so the sidewall available to 'squish' is taller and the tire BFG KM2 is designed to do this with zero issues. The grip and added articulation flex is incredible. The tires alone create a 2" 'lift' when inflated standard psi. The strut spacer sets the ride height at +50mm so that's 4" extra clearance from the ground to various parts on a stock vehicle! Nuts.
 

jwest

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I bet it's for street.

This sort of sarcasm is not helpful to people new to this. If you're going to post something like that you need to also note that it's a joke. Miss-information leads to confusion for newbies.
 

jwest

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Sorry no not sarcastic at all.

Hey no problem. psi that low should basically never be used on the street assuming any normal street speeds which would be unwise aside from rather annoying. Obviously you could choose to drive around the block at 20 psi but why would you want to? ;)
 

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Sorry but much of that *is incorrect. Factory 18’s, no wheel spacer, shorter rod ONLY to keep computer seeing things in its happy range( they are not over correcting to add height)

So, the strut spacer adds 2” to the distance from bottom mount in LCA to top of strut mount hat. My intention and current setting is to have the air strut at its same extension as during stock use. This means the strut is not extended not compressed. However, due to the top strut spacer the axle and hub etc are all dropped by roughly 2”.

Then I used the IIDtool to set the hub center to fender distance to factory + 50mm. Upon writing this I realize I did not account for the geometries occurring around the difference between lca pivot vs strut vs hub. 2” at the hub does equal 2” at the strut unless they got some good parallelogram geometry built in there.

Amyway, hub to fender is at 50mm more.
Regarding the tires, a spacervwoild fender this 100% impossible and I tried that with the less common 25mm wheel spacer. Massive rubbing all over: against the slider, the front bumper, terrible compression issues at upper front bumper and fender flares. Also at the rear it then runs into the wheel arch under compression. Spacers are a killer on these vehicles. Even the compo (10mm right) would screw it up too much for my preference.

I need you to also understand my inner fender spaces are fully modified to remove all bulges and such.

These tires will not work without the strut spacer because under compression you grind the hell out of the fender flares as well as inside the body arch itself. Any loss of air suspension and you would be literally stuck, not just annoying worried stuck, but honestly unable to go as 30% of tire would be jammed into the body arch.

The best worry free size is 32” 275/65-18 but you could experiment with 33” 275/70. Just don’t be a dork and skimp on the necessary physical modifications of cutting and routing things. Remember, rods aren’t a ‘mod’, they add nothing whatsoever.


@jwest

Thanks for your detailed reply. I always appreciate your input. You clearly have a better grasp on these suspensions than I do at this point.

Could you bear with me, and make sure I understand the cumulative effect of each of your changes? I'm considering changes as new tires are coming up, and i have had these Proud Rhino strut spacers sitting in my garage for over 2 years at this point.

Your basic premise, which I agree with if I understand it correctly, seems to be that for whatever largest tire size you can run, best performance is achieved by keeping the air strut pressure and suspension geometry as close to factory "normal" setting as possible. (i.e. In an ideal world we could stuff whatever size tires we wanted under there with no other changes, and still be mobile when on the bumpstops)

So, we start with a truck at stock ride height, air strut pressure, and suspension geometry when at the "normal" setting and then make your changes one at time, cumulatively from there.

Baseline.
Stock truck, "normal" suspension setting. Hub Centerline to fender flare measurements are roughly 465mm front and 485mm rear.

Change 1. Add Proud Rhino Strut 2" strut spacers.
Effect of this change would be as follows. Truck would be at stock height. Air strut would underinflated relative to stock "normal" setting and be in a state of compression by 2". Suspension geometry would be unchanged, as the 2" difference in height of the strut assembly is accommodated by the compression of the air spring.

Change 2. Add "2 inch lift rods"
Cumulative effect of this would be truck is at +2 inches ride height. Air strut inflation and extension would be roughly equivalent to that of stock truck at "normal" setting. Suspension geometry would be equivalent to a stock truck at "offroad" setting.

Change 3. Use IID Tool
Adjust hub centerline to fender flare edge measurements to roughly 515mm front and 525mm rear (stock + 50mm). Effect of this change would be to return suspension geometry to somewhere between factory "normal" and "offroad" setting at the expense of a somewhat lower air strut pressure for a given ride height.

Thus, at the end of the string of changes, you have a truck somewhere between factory "normal" and factory "offroad" height. Air strut pressure somewhere between factory "normal" and factory "access" pressures. Suspension geometry somewhere between factory "normal" and factory "offroad" settings. All of which represents best compromise we can achieve between maintaining factory height, air strut pressure and suspension geometry while achieving our goal of maintaining mobility during a suspension failure while running larger tires.

D@mn, that's a lot to read. PM me your address and I will send you a 12 pack of your favorite beer.

And I have no ego ******* in this, so feel free to shoot holes in it if I am not understanding what you have done, or the effects of your changes.
 

jwest

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dding the strut spacer and doing nothing else...how could that result in same vehicle height? vehicle knows nothing of what you did, so why would the struts now magically allow themselves to compress? the vehicle will only know that the control arms are angled down while it has not told the strut to extend...thus it's confusion and requirement of shorter rods to let it see the sensor back to the factory position.

basically you could put the strut spacer in, then drive as normal but the computer would be 'annoyed' and not lift or lower without a fuss causing fault codes and it saying "oooh nooo you need to shut this down and pull off the road"

number 2, the rod length determines the foolery it provides. it's critical to study up on the reduction lengths needed in order to provide associated foolery. meaning, in my case i wanted exactly the 2" offset amount while some people have used less shortened for less ground clearance foolery.

i like calling it foolery because that's all it is seeing as nothing fundamental changes unfortunately. the control arms go toward their maximum, the cv joint goes towards it's max, etc. the places you see rod length changed to provide 2.5" "lift" in my opinion are total **** and getting your vehicle very close to fukking it up by riding that high all the time. plus there is ZERO need to ride that high on pavement at any speed and at high speeds is ******** and dangerous. This is not lifting like a solid axle vehicle with new dampers, springs, and such to actually keep things correct, safe, and reliable. Thus these extensions should be minor and mostly only off road, even then if you try to be cute and roll at +2-4 full time, your compressor will teach you a lesson.

The beauty of the strut spacer is you can roll full time off road at +2" with zero extra work by the compressor because the strut itself is at the factory neutral length. You have to remember though that when you choose on the terrain dial, mud n ruts or anything beyond hard surface slippery "grass/snow roads", the computer will also say to itself, "oh, you certainly need ligt now too" and it will engage the air lifting it up to standard off road height.

this now will in effect be 4" above the true factory highway height. which is massive actually and sufficient for most situations. it's also right about where the factory system limits the "extended" mode height to protect the cv etc.

What i do on rougher rolling forest roads is use low range for the up/down changes, set Llams to +1 level which is about +20-25mm, and stay out of terrain response unless it were the slick hard surface mode.

When i get to something like our Naches trail here where i've so far only seen beat to hell short wheelbase jeeps besides me, i go ahead and exit llams, choose mud n ruts, often turn off DSC, and take it all in the resulting +4" that "off road height plus the spacers provides. if i get to a particularly harsh break over, ledge "butt drop", or very deep ruts, i then just use llams +20, and have llams +50 if super tricky spot but i exit that max extension the moment it's passed.

I've fully removed a strut trailside to replace and air line into it's top and do not want to do that very often, especially when it's not a beautiful warm sunny day with plenty of time, food, and beer. It would suck massively to do any real suspension repair in the dark, cold, raining, with a girlfriend who wasn't so hot on the "4x4" trail in the first place ;)
 

avslash

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^ still, "NO" to 1 and partially 2 ;)


Ok. I'm officially lost then, and going to the corner with my dunce hat...:) I shouldn't have skimped on the second semester of logic in school.

If you have time to correct where my logic is errant or point out what I am missing, the beer offer stands.
 

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