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Highline or Lift?

jjvw

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Feb 17, 2018
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@toximus Just trying to find out information, how are you both using more than 4 inches of up travel on the road? Does your jeep lean that much when making turns?
We both have more than the factory amounts of shock travel. The lean is controlled by shocks and sway bars. It does exist. Though, the bulk of the travel is simply the axles being able to move up before transmitting that motion into the frame/body just driving down the street. It goes a long ways toward a comfortable ride.
 
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jodomcfrodo

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Feb 24, 2016
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At the risk of getting nitpicky (again), does anyone know what LCoG really means for a Jeep build? I don't. Except that an overarching desire for the idea of LCoG brings with it the very real risk for compromises that can overshadow other important considerations than where the center of gravity happens to be.

This is a reason why paying attention that factory 4" of up travel is meaningful. It focuses one's thinking into an area of objectivity. The rest of the build will fall into place depending on what you want to do with that measurement.
I'm one of the last remaining people who still likes the idea of LCOG. This is my thinking (whether it is right or wrong, I don't know).

I'm definitely not a fan of slamming too big of tires on with too small of a lift. I want up travel so I can cruise around comfortably, whether that be on-road or off-road. But at the same time, I value being able to point my Jeep at a very steep climb without worrying about rolling over backwards. When I think about a good LCOG build, I usually think something along the lines of 37's, 2.5" - 3" lift, 1.25" BL, relocated shock mounts, 100" WB, and highlines. Something like this is eventually where I'd like my Jeep to be. What up-travel numbers I'm going to get out of that, I have no clue. But I don't think that build philosophy is going to cause too many compromises.

At the end of the day, I think what up travel numbers and COG you're shooting for really depends on what you want to do with the Jeep. If I wanted to race through the desert, I'd be maximizing my up travel and looking at 8"+ if I was getting serious about it. But for what I like to do, slow crawling and steep / off-camber obstacles, I think a lower Jeep is better.

Some of my ideas on this come from comparing apples to oranges. I've attached a photo and a video of the buggy I was able to drive in Moab a few years ago. I've never driven a vehicle off-road that seemed so stable. You could point this thing at pretty much anything and it would crawl right up with no drama (no hopping, no feeling the front end getting light, nothing). There was one climb on Poison Spyder where a TJ with a 5.5" long arm almost ended up rolling over and was saved by the tire carrier. I drove this buggy right up with absolutely no problems what-so-ever. Whether it is possible to get buggy-like performance out of a TJ, I'm not sure. But I would like to get as close as humanely possible.

The buggy is pretty low when considering it is sitting on 42's. It is also a lot wider and a lot longer than a TJ. I know I am comparing two COMPLETELY different things, but I still think there is something to be learned.


94109


 

Kevin Bright

Another Part, and another and another and another
Supporting Member
I'm one of the last remaining people who still likes the idea of LCOG. This is my thinking (whether it is right or wrong, I don't know).

I'm definitely not a fan of slamming too big of tires on with too small of a lift. I want up travel so I can cruise around comfortably, whether that be on-road or off-road. But at the same time, I value being able to point my Jeep at a very steep climb without worrying about rolling over backwards. When I think about a good LCOG build, I usually think something along the lines of 37's, 2.5" - 3" lift, 1.25" BL, relocated shock mounts, 100" WB, and highlines. Something like this is eventually where I'd like my Jeep to be. What up-travel numbers I'm going to get out of that, I have no clue. But I don't think that build philosophy is going to cause too many compromises.

At the end of the day, I think what up travel numbers and COG you're shooting for really depends on what you want to do with the Jeep. If I wanted to race through the desert, I'd be maximizing my up travel and looking at 8"+ if I was getting serious about it. But for what I like to do, slow crawling and steep / off-camber obstacles, I think a lower Jeep is better.

Some of my ideas on this come from comparing apples to oranges. I've attached a photo and a video of the buggy I was able to drive in Moab a few years ago. I've never driven a vehicle off-road that seemed so stable. You could point this thing at pretty much anything and it would crawl right up with no drama (no hopping, no feeling the front end getting light, nothing). There was one climb on Poison Spyder where a TJ with a 5.5" long arm almost ended up rolling over and was saved by the tire carrier. I drove this buggy right up with absolutely no problems what-so-ever. Whether it is possible to get buggy-like performance out of a TJ, I'm not sure. But I would like to get as close as humanely possible.

The buggy is pretty low when considering it is sitting on 42's. It is also a lot wider and a lot longer than a TJ. I know I am comparing two COMPLETELY different things, but I still think there is something to be learned.


View attachment 94109

View attachment 94110
Our ideal LCOG builds are exactly the same
 
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toximus

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Mar 29, 2018
2,377
Northern WI
@toximus Just trying to find out information, how are you both using more than 4 inches of up travel on the road? Does your jeep lean that much when making turns?

We both have more than the factory amounts of shock travel. The lean is controlled by shocks and sway bars. It does exist. Though, the bulk of the travel is simply the axles being able to move up before transmitting that motion into the frame/body just driving down the street. It goes a long ways toward a comfortable ride.
Having a dual rate antisway bar on mine I get less body roll (lean) than most on the street. Bumps, pot holes, and similar are contributing factors. Larger than stock tires (meaning more unsprung weight) is also more difficult to control. All things combined, my Jeep rides better than a stock Jeep.
 

Jerry Bransford

TJ Guru
Supporting Member
Nov 9, 2015
11,180
Escondido California
I'm one of the last remaining people who still likes the idea of LCOG. This is my thinking (whether it is right or wrong, I don't know).

I'm definitely not a fan of slamming too big of tires on with too small of a lift. I want up travel so I can cruise around comfortably, whether that be on-road or off-road. But at the same time, I value being able to point my Jeep at a very steep climb without worrying about rolling over backwards. When I think about a good LCOG build, I usually think something along the lines of 37's, 2.5" - 3" lift, 1.25" BL, relocated shock mounts, 100" WB, and highlines. Something like this is eventually where I'd like my Jeep to be. What up-travel numbers I'm going to get out of that, I have no clue. But I don't think that build philosophy is going to cause too many compromises.

At the end of the day, I think what up travel numbers and COG you're shooting for really depends on what you want to do with the Jeep. If I wanted to race through the desert, I'd be maximizing my up travel and looking at 8"+ if I was getting serious about it. But for what I like to do, slow crawling and steep / off-camber obstacles, I think a lower Jeep is better.

Some of my ideas on this come from comparing apples to oranges. I've attached a photo and a video of the buggy I was able to drive in Moab a few years ago. I've never driven a vehicle off-road that seemed so stable. You could point this thing at pretty much anything and it would crawl right up with no drama (no hopping, no feeling the front end getting light, nothing). There was one climb on Poison Spyder where a TJ with a 5.5" long arm almost ended up rolling over and was saved by the tire carrier. I drove this buggy right up with absolutely no problems what-so-ever. Whether it is possible to get buggy-like performance out of a TJ, I'm not sure. But I would like to get as close as humanely possible.

The buggy is pretty low when considering it is sitting on 42's. It is also a lot wider and a lot longer than a TJ. I know I am comparing two COMPLETELY different things, but I still think there is something to be learned.


View attachment 94109

View attachment 94110
An unlifted vehicle sitting on 42's has 6" additional ground clearance over an unlifted vehicle with 30" tires. And there's no doubt he has some sort of suspension lift increasing it well above 6" of ground clearance. 6" of ground clearance is only obtainable by us more typical Jeepers without 40's by running 33" tires and 4.5" suspension lifts or some other combination. So that 40" tire example is not exactly helpful since those 40" tires lift it as much as most suspension lifts do. Not to mention, again, that Jeep is very likely to also have some sort of suspension lift too.

Do we build our Jeeps to have high centers of gravity? Of course not. But in my personal opinion the the whole COG thing is unnecessarily worried about by some. Especially those who don't do trails that are full of steep climbs and/or off-camber sections and are scared their vehicles are going to roll over or tip over backwards on sections that are just not likely to do that.

To me, ground clearance is more important than an extra-low COG is when going offroad. Going with the lowest possible suspension lift height in the interest of an extra low COG is just not my idea of a realistic or desirable design goal. But one thing I have noticed is this... the newer the Jeeper or the less amount of offroad experience he has, the more worried he'll be about rolling over. Our TJs can be at steeper angles than less experienced Jeepers would imaging.

Here's a pic of a guy with a Jeep (built by mrblaine) that was not designed as a low COG vehicle. Will many get their Jeeps tipped over as far as is shown here? Nope. Did his flop/tip-over after this photo was taken? Nope. Was the camera tilted to make it look more tipped over than it really was? Nope. :)

Jon in Johnson Valley.JPG

CrawlMagazineJonsJeep.jpg


This is me in my previous TJ on an exceptionally tough section of trail called the Gatekeeper in Doran Canyon SoCal. Nope my TJ didn't roll and I was able to drive unassisted out of that situation.

CalicoTippedOver.jpg


2003_0118_114343AA.JPG


Incidentally that section of trail I was on in those two pics has gotten significantly tougher, I don't even consider going up that part of Doran Canyon any more. Us mere mortals now use a bypass around that particular section of trail.
 
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toximus

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Mar 29, 2018
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Northern WI
I value being able to point my Jeep at a very steep climb without worrying about rolling over backwards.
We may start worrying at different points, but that actual tipping point is probably more than either of us think it is. I rely on 4-link geometry and weight distribution to prevent rolling over backwards (wheelie).

a TJ with a 5.5" long arm almost ended up rolling over and was saved by the tire carrier
I have a problem with everything you mentioned as part of this build. None of that helps or is what I'd suggest having.
 

jjvw

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Feb 17, 2018
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Colorado, USA
I don't know if that buggy is LCoG or not. That particular label becomes less significant when other details are considered. That type of build becomes increasingly difficult to compare to what most of us are driving. When a Jeep isn't much of a Jeep anymore things like shock travels and frame heights need to be looked at instead. I would like to think there is more than 4" of up.

Regarding the TJ that almost rolled, how do we know that was because of the COG?
 
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Alex01

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While on the topic of stability how do you feel about up vs down travel. 50/50 or do you prefer to favor one over another? I would think a LCoG build would have far more down then up travel unless the mounts were moved.
 

toximus

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Mar 29, 2018
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Northern WI
While on the topic of stability how do you feel about up vs down travel. 50/50 or do you prefer to favor one over another? I would think a LCoG build would have far more down then up travel unless the mounts were moved.
If you have the choice, 50/50 works well.

Also, if one is concerned about COG on a steep climb could a suck down winch come into play?
I think we're worrying about it more than it is a problem.
 

jodomcfrodo

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Feb 24, 2016
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Evanston, IL, United States
I think what I value most off-road is stability. I don't like hopping while climbing and I don't like the front end getting light and sliding around on me. I'm not sure what factors play into those two things, but I'll mention a couple of things that come to mind for me.

- Changing from a hardtop to a soft top made a noticeable difference off-road in terms of stability. I haven't had my hard top on in a while because of that.

- I have a buddy who has driven my Jeep a few times and rides in it quite often. I had a 1.25" body lift installed and 35"s put on my TJ a few months back. First thing he said on his first ride with those modifications installed was "woah, your sway bars are loose". Something he had never mentioned before when I had 33's and no body lift. So it seems like there is a noticeable difference with seemingly small changes.

- Just from physics, something with a lower COG is going to be able to lean more severely without tipping over. The COG is going to remain vertically over the base of the object for a higher angle (poorly worded, but hopefully that makes sense). You can increase the tipping angle by either making the base larger (wider axles, longer wheelbase) or by lowering the COG.

Let me ask this. Say you put two nearly identical Jeeps at the same angle using a forklift or something similar. But one Jeep has a 4" lift and the other Jeep has a 2" lift. Will the 2" lift Jeep be able to be put a steeper angler before tipping over? In my mind yes, but I'm open to hear thoughts on that.
 

toximus

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Mar 29, 2018
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Northern WI
Let me ask this. Say you put two nearly identical Jeeps at the same angle using a forklift or something similar. But one Jeep has a 4" lift and the other Jeep has a 2" lift. Will the 2" lift Jeep be able to be put a steeper angler before tipping over? In my mind yes, but I'm open to hear thoughts on that.
I wheel on a trail and not on forklifts.
 
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jjvw

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From what I've seen, most "LCoG" builds are heavily biased towards down travel.

Something to consider is that the further a tire can be pushed up, the less the body will be shoved up and over by that rising tire. This is an area of added stability and control that LCoG builds do not benefit from. In fact, that aspect of stability is often reduced, despite the desire to build a more stable Jeep.

Those of us who are critical of LCoG are not against a low center of gravity. Most of us are opposed to a needlessly high center of gravity (wherever that is). We are critical of placing too much focus on that one area. Especially when it is at the expense of other important aspects of the build.

Mine currently has a bit more up than down. I think when more gets sorted and settled, it will be closer to 50/50.
 
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Jerry Bransford

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From what I've seen, most "LCoG" builds are heavily biased towards down travel.

Something to consider is that the further a tire can be pushed up, the less the body will be shoved up and over by that rising tire. This is an area of added stability and control that LCoG builds do not benefit from. In fact, that aspect of stability is often reduced, despite the desire to build a more stable Jeep.

Those of us who are critical of LCoG are not against a low center of gravity. Most of us are opposed to a needlessly high center of gravity (wherever that is). We are critical of placing too much focus on that one area. Especially when it is at the expense of other important aspects of the build.
Exactly, well said, and better said than my own contribution above. Those are important nuances not grasped by many.
 

jodomcfrodo

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Feb 24, 2016
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Evanston, IL, United States
I wheel on a trail and not on forklifts.
I guess I'll head back to the mall then. Question still stands if you want to give it a shot.


From what I've seen, most "LCoG" builds are heavily biased towards down travel.

Something to consider is that the further a tire can be pushed up, the less the body will be shoved up and over by that rising tire. This is an area of added stability and control that LCoG builds do not benefit from. In fact, that aspect of stability is often reduced, despite the desire to build a more stable Jeep.

Those of us who are critical of LCoG are not against a low center of gravity. We are critical of placing too much focus on that one area. Especially when it is at the expense of other important aspects of the build.

Mine currently has a bit more up than down. I think when more gets sorted and settled, it will be closer to 50/50.
What about this. Take a completely stock TJ and change nothing besides adding a 4" lift. From my understanding, that Jeep will now have 8" of up travel (assuming tires are still stock as well). If you head out on the trail with a non-lifted stock Jeep, which Jeep is going to lean more on a given obstacle? Which is going to have more trouble with climbing?

My intuition is that the Jeep with the lift will lean less while climbing over a boulder with one tire since the up travel is going to take up more of the lean. The tire will move up instead of the body. But when you get all 4 tires on a steep climb or 2 tires on an off camber obstacle, the Jeep with the lift is going to lean a lot more.
 

Alex01

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If you have the choice, 50/50 works well.
I think we're worrying about it more than it is a problem.
As far as the suck down winch goes I'm asking out of general curiosity not trying to solve any issues. Recently just read about them.

Mine currently has a bit more up than down. I think when more gets sorted and settled, it will be closer to 50/50.
Mine currently sits around 50/50 but I'm installing smaller shocks in order to get more up travel so it will be closer to 65/35 up. But, I'll only be losing around 1 inch of usable down travel. In doing so though I can take off 1.25 of bump. I'm really interested how things will measure out once I get the new shocks in and how it will feel on the trails.
 

jjvw

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....


Mine currently sits around 50/50 but I'm installing smaller shocks in order to get more up travel so it will be closer to 65/35 up. But, I'll only be losing around 1 inch of usable down travel but take off 1.25 of bump. I'm really interested how things will measure out once I get the new shocks in and how it will feel on the trails.
Weren't you going to raise the front upper shock mount?
 
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Alex01

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Weren't you going to raise the front upper shock mount?
I went over to @bobthetj03 and the TB was still interfering with the uptravel so we didn't do anything. I finally got it sorted out by centering the axle a bit better. My short term solution is to put smaller shocks in then decide if I want to go all out and get fox shocks, sweet talk @bobthetj03 into allowing me swing by again for round 2 to make the extensions for the ranchos, or leave the smaller bodied shocks in.
 
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Jerry Bransford

TJ Guru
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Nov 9, 2015
11,180
Escondido California
What about this. Take a completely stock TJ and change nothing besides adding a 4" lift. From my understanding, that Jeep will now have 8" of up travel (assuming tires are still stock as well). If you head out on the trail with a non-lifted stock Jeep, which Jeep is going to lean more on a given obstacle? Which is going to have more trouble with climbing?

My intuition is that the Jeep with the lift will lean less while climbing over a boulder with one tire since the up travel is going to take up more of the lean. The tire will move up instead of the body. But when you get all 4 tires on a steep climb or 2 tires on an off camber obstacle, the Jeep with the lift is going to lean a lot more.
You are unnecessarily obsessed with lean. You just have to get over that problem with lean since it is normal if you're not staying on flat easy trails.

Did you not take a good hard look at that blue TJ that is tipped WAY over yet it didn't flop over? Or my red TJ leaning over nearly if not as far? Jeeps will lean on trails. My wife started literally shrieking on a VERY slightly off-camber section of trail. We were barely (BARELY) at an angle yet because she was new to offroading, it freaked her out. I stopped the Jeep at that point, helped her out, and we both walked behind the Jeep so she could see the very (!) slight couple-degree angle it was at. When she saw it, then she realized it wasn't much of an angle at all but inside the Jeep, her stomach and mind put her into a panic thinking we were about to roll.

As said above, the newer the Jeeper is to offroading, the more such relatively minor angles will scare them. Again, take a look at the blue TJ above and my red TJ. Neither flopped onto the side. You just have to recalibrate your stomach and mind so they're no longer worried about such things. Like a pilot gets used to steep turns, aerobatics, etc. that would scare a non-pilot sitting next to him.