How steep can you climb?

[txj2go]

I don't know if this is the Steepest I have tried, but at 36 degree you are basically looking straight at the sky.
But if you take a picture from the outside, it looks like its nothing more than a steep driveway lol

I don't know what the limit is with good tires. It would be interesting to take an angle-finder along and measure some of the steep stuff on Fins and Things for instance. I have an idea that you are there or getting really close at 36 degrees and it always looks like less in photographs than it does when you are there. Is the limit 40 degrees or 44 degrees? I have KO2 tires from a Rubicon, are there other brands with better traction on slickrock? I think Fins and Things might have some of the steepest smooth surfaces, you can find videos of people essentially sitting on place and spinning all of their tires.

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[RubiSc0tt]

There are a lot of variables which others have discussed here more in depth. What I will say is this:
it takes a while to get used to all this, and driver experience (seat time) can be a huge factor.

Case in point: several years back we were out on an easy trail. 2 04 TJ Rubi's on 33's and short arm kits, and an LJ Rubi on 35's w/ a Long arm kit. It was essentially a Step up ledge on a 90 degree turn where you had to steer into the wall on the driver side so your tires would grab and gain traction to get over a few rocks on the passenger side.

Me and my buddy in the other TJ had experience and had done this trail a few times, so we drove it like it was the Dunkin Donuts drive through, first try, no contest. My buddy in the LJ had less experience than us and was freaked out. He said he felt like he was about to roll, despite the longer more stable wheel base, long arm kit (more flex and stability), and 35" tires.

So we had him put it in Park, shut down, get out, and walk around the rig. He had no idea how it looked vs. how it looked in the driver seat. Once he walked around it, he realized he was in no danger. He got back in and a few more tries, drove it no problem. We talked about it after and how deceptive that particular obstacle can be from the driver seat, and how his Jeep was built more capable than either of ours. This gave him the confidence he needed to drive harder obstacles. It was still uncomfortable at first, but he always talked about that after and how that was a moment for him to realize how actually capable his Jeep was, and that he was the limiting factor.

 

[jadmt]

also 2 door vs 4 door make a world of difference. things that feel like nothing in a 4 door will have the front wheels off the ground in a 2 door.

 

[Ratbert]

Of course I could ask who understands what is in the differential, how it works, how lockers affect how it works and what this does to the tires of the vehicle. There are times when a locker doesn't do anything to the tires of the vehicle so it doesn't matter if it is on or off. I used to be a mechanic so I know what's in there and how it works. I've also seen vehicles with open differentials where one tire was limited in traction and what that caused.

Maybe I should attack this in a different way.

The Jeep will climb the best when all 4 tires are achieving maximum traction which means there is not much articulation side to side. If the Jeep is articulating side to side this will reduce traction on 2 of the tires because they are being unloaded, and this will reduce climbing ability due to 2 tires pulling 100% and 2 tires pulling less than 100%. The farther you go from all 4 tires pulling 100% the more likely lockers are to help you but they won't do anything to make a tire pull more than it can when it is being unloaded. The lockers will protect the ability of the other tires to keep pulling but at that point you are limited in how much pull you can get on 2 or 3 out of 4 tires and therefore how much slope that you can climb.

It's not too uncommon to be in uneven terrain and have the Jeep essentially balancing on 2 tires, one tire up in the air and the 4th tire barely touching the ground. In this case only 2 tires are doing all of the pulling. You won't have as much traction with 2 tires pulling as you will with 4 tires pulling but the lockers will insure that the 2 tires that have good traction can still pull.

The opposite of this is having all 4 tires pressed evenly to the ground so they can all achieve their maximum traction and in this situation lockers don't make any difference. Lockers only matter when a tire on one side is slipping, if all 4 tires are pressed evenly to the ground no individual tire is trying to slip prematurely so the tires don't know if you do or do not have lockers.

The steepest Colorado trail I've been on was climbing Round Mountain. Like a lot of Colorado trails Its surface is not optimum for traction and was almost steep enough that I could sit in one spot and spin all 4 tires. The steepest Utah trail I've been on is part of Elephant Hill. Being Utah it is a very sticky surface but the steepest parts didn't seem to provide much articulation and the Jeep drove up without much drama.

This thread was strictly about how steep can you climb, not when lockers are beneficial. The steepest you can climb will be something smooth enough that the tires don't articulate
and therefore lockers aren't a benefit. I didn't say lockers hurt anything, I don't think they ever hurt anything when you aren't on pavement but they aren't as necessary as beginners might think. I don't think they are needed until you are on 5 and greater trails such as in Utah. I don't have lockers, I don't do those trails so I have not needed them. My daughter has done trails in Colorado in her Jeep rated difficult by Wells and didn't need lockers. We were on the most difficult obstacle on Argentine Pass and she had one tire pretty far up in the air but still did the obstacle without lockers. However she wouldn't do the 5+ rated trails in Utah either.

I don't drive on frozen stuff, I don't know how much benefit there is to lockers there.



I wasn't saying they were a disadvantage, they might or might not be an advantage depending on the situation. If you understand what a locker does and what that does to the tires then you have more understanding of when they are an advantage and when they are not.

I once owned a car with a welded differential, the simplest and most direct form of locker. We only drove it on pavement and when going around a corner you could hear one of the tires chirping. If you are driving a vehicle that forces one of the tires to lose traction in some situations you can understand that might not be best for traction. It would be a somewhat rare situation for this to affect offroad behaviour. I've seen some of the trails in Fins and Things where maybe this could apply.

If you're going up something extremely steep and one wheel loses grip (hits sand or whatever) then a locker will transfer that torque to the wheel that has traction. Without lockers that wheel will just uselessly spin unless something like brake locking is used to slow it down.

Note that earlier you said you were on Rubicon tires. That doesn't tell us shit.

 

[txj2go]

also 2 door vs 4 door make a world of difference. things that feel like nothing in a 4 door will have the front wheels off the ground in a 2 door.

That picture certainly looks like 45 degrees. I have 30 degree and 45 degree drafting triangles at my desk so I hold them up to the screen, it is somewhere close to halfway between the 2 triangles, certainly could be close to 40 degrees. That's also assuming that the camera is held perfectly vertical.

If you're going up something extremely steep and one wheel loses grip (hits sand or whatever) then a locker will transfer that torque to the wheel that has traction. Without lockers that wheel will just uselessly spin unless something like brake locking is used to slow it down.

Actually without lockers the wheel that is up in the air will spin and no torque will go to the wheel that is still on the ground (without limited slip or brake locking). This affects the 2 tires on the other end of the Jeep too, whatever has picked up on the corner to raise a front tire off the ground will be trying to do the same thing to a tire in the back and will reduce traction there too. The only thing that prevents this is having slightly different weight distribution front to back, otherwise the car could set there only on 2 tires and balance just fine. That's the advantage of the locker, it will force torque to the tire that is still on the ground but in the end you won't climb as much with 2 wheels firmly on the ground as you will with 4 on the ground.

 

[Zandcwhite]

Of course I could ask who understands what is in the differential, how it works, how lockers affect how it works and what this does to the tires of the vehicle. There are times when a locker doesn't do anything to the tires of the vehicle so it doesn't matter if it is on or off. I used to be a mechanic so I know what's in there and how it works. I've also seen vehicles with open differentials where one tire was limited in traction and what that caused.

Maybe I should attack this in a different way.

The Jeep will climb the best when all 4 tires are achieving maximum traction which means there is not much articulation side to side. If the Jeep is articulating side to side this will reduce traction on 2 of the tires because they are being unloaded, and this will reduce climbing ability due to 2 tires pulling 100% and 2 tires pulling less than 100%. The farther you go from all 4 tires pulling 100% the more likely lockers are to help you but they won't do anything to make a tire pull more than it can when it is being unloaded. The lockers will protect the ability of the other tires to keep pulling but at that point you are limited in how much pull you can get on 2 or 3 out of 4 tires and therefore how much slope that you can climb.

It's not too uncommon to be in uneven terrain and have the Jeep essentially balancing on 2 tires, one tire up in the air and the 4th tire barely touching the ground. In this case only 2 tires are doing all of the pulling. You won't have as much traction with 2 tires pulling as you will with 4 tires pulling but the lockers will insure that the 2 tires that have good traction can still pull.

The opposite of this is having all 4 tires pressed evenly to the ground so they can all achieve their maximum traction and in this situation lockers don't make any difference. Lockers only matter when a tire on one side is slipping, if all 4 tires are pressed evenly to the ground no individual tire is trying to slip prematurely so the tires don't know if you do or do not have lockers.

The steepest Colorado trail I've been on was climbing Round Mountain. Like a lot of Colorado trails Its surface is not optimum for traction and was almost steep enough that I could sit in one spot and spin all 4 tires. The steepest Utah trail I've been on is part of Elephant Hill. Being Utah it is a very sticky surface but the steepest parts didn't seem to provide much articulation and the Jeep drove up without much drama.

This thread was strictly about how steep can you climb, not when lockers are beneficial. The steepest you can climb will be something smooth enough that the tires don't articulate
and therefore lockers aren't a benefit. I didn't say lockers hurt anything, I don't think they ever hurt anything when you aren't on pavement but they aren't as necessary as beginners might think. I don't think they are needed until you are on 5 and greater trails such as in Utah. I don't have lockers, I don't do those trails so I have not needed them. My daughter has done trails in Colorado in her Jeep rated difficult by Wells and didn't need lockers. We were on the most difficult obstacle on Argentine Pass and she had one tire pretty far up in the air but still did the obstacle without lockers. However she wouldn't do the 5+ rated trails in Utah either.

I don't drive on frozen stuff, I don't know how much benefit there is to lockers there.



I wasn't saying they were a disadvantage, they might or might not be an advantage depending on the situation. If you understand what a locker does and what that does to the tires then you have more understanding of when they are an advantage and when they are not.

I once owned a car with a welded differential, the simplest and most direct form of locker. We only drove it on pavement and when going around a corner you could hear one of the tires chirping. If you are driving a vehicle that forces one of the tires to lose traction in some situations you can understand that might not be best for traction. It would be a somewhat rare situation for this to affect offroad behaviour. I've seen some of the trails in Fins and Things where maybe this could apply.

I think most of us understand how lockers work. But to argue they won't help in a steep climb because you won't have all 4 tires pulling is absurd. Steep, articulated climbs are the only place I ever NEED the lockers. Obviously if we are trying to determine the steepest angle you could climb, it being flat and rough textured for maximum traction would be ideal. In that scenario you'll have enough traction to roll over backwards so it's kind of irrelevant. As far as real world obstacles where the tires won't have even weight on them and they may have wildly different traction even if they have the same weight (sand/mud/loose dirt under 1 or 2 tires and slickrock under the other 2) I'll still bet you can climb an obstacle better with lockers than without. The BLD definitely closes the margin between open diffs and lockers but the lockers will offer an advantage all things being equal.

 

[jadmt]

it was bouncing between 44-45° but always hard to get the prefect photo when you feeling like tipsy lol....

 

[txj2go]

But to argue they won't help in a steep climb because you won't have all 4 tires pulling is absurd.

That's not what I was saying.

Steep, articulated climbs are the only place I ever NEED the lockers.

That IS what I was saying. You NEED lockers when articulation reduces traction on 2 of the tires. But if you need lockers when articulation is significant then you don't need them when there is no articulation. We were talking about maximum climbing which can only happen on a smooth surface when the lockers aren't doing anything.

Obviously if we are trying to determine the steepest angle you could climb, it being flat and rough textured for maximum traction would be ideal. In that scenario you'll have enough traction to roll over backwards so it's kind of irrelevant.

That's what we're talking about- maybe it's mostly a hypothetical discussion except for a few trails in Utah. There are obstacles like this in Utah- uniform surface but steep, textured enough for good grip, and people lose traction on all 4 tires before they are at an angle that they can tip over backwards.

Maybe I should say also I'm talking about us in our Jeeps. I've seen the crazy things people do in buggies. I don't know how much steeper they can go than a highway worthy Jeep but when I see them tip over I think that is as much due to their action of keeping up momentum and bouncing on the rocks as it is the angle they are at.

Note that earlier you said you were on Rubicon tires. That doesn't tell us shit.

I only said that because I was wondering how much traction ability there is for one tire brand vs. another. I wasn't trying to say anything else. I have a 2018 Sport with Rubicon tires, 4-door, 3.6L, 8-speed. It has the stock Sport drivetrain meaning not as much crawl ratio as the Rubicon, no lockers, no angle display in the dash, no easy way to disconnect sway bar end links. I think it has the ability to spin all 4 tires on the steeper slopes of Fins and Things but I've never tried that. Whether it would actually climb them I don't know. I make 3-4 trips to Utah and Colorado each year to do trails. I don't do the 5+ trails in either state, that's not what I bought the Jeep for.

 

[Zandcwhite]

That's not what I was saying.


That IS what I was saying. You NEED lockers when articulation reduces traction on 2 of the tires. But if you need lockers when articulation is significant then you don't need them when there is no articulation. We were talking about maximum climbing which can only happen on a smooth surface when the lockers aren't doing anything.


That's what we're talking about- maybe it's mostly a hypothetical discussion except for a few trails in Utah. There are obstacles like this in Utah- uniform surface but steep, textured enough for good grip, and people lose traction on all 4 tires before they are at an angle that they can tip over backwards.

Maybe I should say also I'm talking about us in our Jeeps. I've seen the crazy things people do in buggies. I don't know how much steeper they can go than a highway worthy Jeep but when I see them tip over I think that is as much due to their action of keeping up momentum and bouncing on the rocks as it is the angle they are at.

If you can't get enough traction on slickrock to roll over backwards your tires are over inflated. In both the JLUR and my old XJ have had to panic reverse with both front tires off the ground. Had I stayed in the throttle they both would have gone over. My buddy rolled a K5 blazer over backwards. It can and will happen given enough angle and enough traction.

 

[jadmt]

If you can't get enough traction on slickrock to roll over backwards your tires are over inflated. In both the JLUR and my old XJ have had to panic reverse with both front tires off the ground. Had I stayed in the throttle they both would have gone over. My buddy rolled a K5 blazer over backwards. It can and will happen given enough angle and enough traction.

100%. I am actually surprised it does not happen more often.

 

[txj2go]

100%. I am actually surprised it does not happen more often.

Staring up at the clouds is one thing, rolling over backwards is a whole different level.

 

[Zandcwhite]

Staring up at the clouds is one thing, rolling over backwards is a whole different level.

Not the best video, but shows just how easily it can happen.

 

[txj2go]

Not the best video, but shows just how easily it can happen.

I've seen Rory climb a buggy up the side of a cargo container, if you go far enough with that you will go over backwards. I don't know how this compares to climbing a uniform slope. When I've watched the buggies there is some "hold my beer" involved there meaning part of their problem is bouncing caused by momentum, Rory went up the container pretty slowly and the video just posted is pretty slow.

The forum software suggested some other old threads. In one of them there is discussion of 47 degree and up to 60 degree slopes.

 

[Zandcwhite]

I've seen Rory climb a buggy up the side of a cargo container, if you go far enough with that you will go over backwards. I don't know how this compares to climbing a uniform slope. When I've watched the buggies there is some "hold my beer" involved there meaning part of their problem is bouncing caused by momentum, Rory went up the container pretty slowly and the video just posted is pretty slow.

The forum software suggested some other old threads. In one of them there is discussion of 47 degree and up to 60 degree slopes.

A 2dr is far more likely to go over backwards, but it is definitely possible even in a 4dr. This one is a combo of too much throttle and too steep, but he wasn't bouncing simply had enough traction to drive it over backwards.

 

[21JLURDG]

100%. I am actually surprised it does not happen more often.

Rolling over backwards probably happens more often than we think. Just that it's not always caught on video. This is from attempting to climb a small wet waterfall using the tire sidewalls on the rock wall. The Creepy Crawlers sidewall had a lot more traction than expected and I was too slow getting into reverse before I went over backwards. A new grille, hood, windshield, soft top, and tire carrier, plus a big hammer on the fender and a roll bar patch, and it was good as new...sort of.

Funny part was that when the spectators all gasped, my 10-year daughter instead turned to her friend and said: "It's ok, my dad does that all the time." She'd previously been in one of my rollovers.

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