Rubicon having issue going up the same terrain while sport easily went up

[mgroeger]

I understand the differences between LSD, lockers and open diff. I was trying to clarify BLD. Is this where as one wheel spins the brakes will gently tap it so that the power is transferred over to the other wheel? I'm familiar with that but never heard the BLD term before.
On a side note I have a Detroit Locker in my LJ and I can't stand the clunkiness of it but it is a beast off road.

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[Mordin Solus]

I am a total noob when it comes to Jeeps and off-roading. Most of the comments here are over my head and I had to look up what BLD means.

This past Saturday I went off-roading for the first time (Ok I went off road back in the mid 80's but that was more just being a crazy kid). I was with an experienced Jeeper and the plan was to do easy stuff (park ratings were 1-5, so 1-2 was what I expected. We end up meeting some friends of hers who were doing a noob run, but were going to hit harder trails. "Nothing you can't handle" is what i was told. I ended up on 3-4 level trails.

I am bone stock Rubicon 2-door. a couple of people had 35 and lifts along with other mods, everyone else 37 and lift and crazy mods. One guy was there with a Sport S on 37's with a lift and had hit the lower level trails a couple of times before.

Not only did we hit harder trails, they were really muddy from heavy rains. The experienced people had little to no issues, though they commented it was much harder and the paths had changed with the rains. The Sport got stuck at one point and had to be winched up.

I got a little stuck once but someone got out and gave a little push which got me up. I think if I had my lockers on at that time I would have been fine. But being a noob I didn't think to use them until someone mentioned it. And it certianly helped on the remaining tough parts.

My point here? A bone stock Rubicon was able to keep up with the big boys easily and it had NOTHING to do with skill.

Trust me, this really was my first time and when I go back I just want to hit the lower level trails a few times to actually learn what to do.

 

[mgroeger]

You experienced the beauty of the Rubi. Off the show room floor you can hit the trails as is. A simple $180 budget lift will get you some more clearance and you will be set for what you will be doing. Kevin8086 ran that lift and everything else stock on a JLUR and conquered some pretty gnarly trails.
Welcome to off roading, it's addictive and fun. Lockers rock, we don't have them on my wife's Sahara but I do on my LJ and wow what a difference.

 

[panda234]

Ok let me start by saying that I’m not challenging rubicons superiority over sport. I’m not crazy and don’t believe in conspiracies. This is A mystery to me.
This is not the first incident that this issue has occured .
My sport without lockers can easily go up the terrains that my cousins rubicon gets stuck and would need to use his lockers.
It seems as though rubicon does not have the BLD option and therefore use of lockers is mandatory when about to get stuck.
Both of us are new to off-roading and I have no doubt as terrains get more difficult he would have the advantage
Please look at both videos I took today.
The blue wrangler is rubicon

The brake lock differential has done a damn fine job getting me out of trouble
It’s wirth mentioning that I also have the limited slip differential as well

Try driving up the same hill with both vehicles in 2WD. I think the Sport will probably make it up in a fairly straight forward fashion, and while the Rubicon will probably get you up as well, it will struggle a lot more. When going uphill, the weight of the vehicle is shifted substantially to the rear wheels, so have an LSD on the rear makes a big difference. Even in 4WD it will make a substantial difference, although the difference is masked a bit by the 4WD. With the Rubicon, you'll have to wait until the BLD kicks in, and by then you've lost most (all?) of your momentum, and it's a lot tougher to get it going again. This is because of the difference in the way an LSD and BLD work.

Traditional LSDs like you can get on a Sport and Sahara kind of work the opposite way of BLD. The LSD has clutch packs connecting the two axles together; it basically operates like a locked differential until a certain amount of force is exerted to overcome the friction of the clutch pack. This breakaway force is designed to be lower than the force typically exerted on the street when going around a corner, so every time you go around a corner in the dry with an LSD the clutch pack is slipping as necessary to allow the tires to spin at different rates. When the force is lower such as when driving in snow and ice or in various situations offroad, the clutch pack exerts enough force to keep both tires turning. So an LSD works great in the majority of offroad situations.

The problem for offroading occurs when one wheel has good traction, the other wheel doesn't, and the amount of power needed to move the vehicle exceeds the amount of force needed to overcome the friction of the LSD clutch pack. This typically happens in more extreme offroad situations such as rock climbing on a steep slope with only one wheel having good traction. In this case, the engine power will overcome the clutch pack and spin the wheel with less traction while there isn't enough force being exerted by the clutch pack on the wheel with good traction to get up and over the obstacle. This is why Rubicons have true locking differentials with no clutch packs to slip.

The BLD works on a different principle. It has speed sensors on the axle, and when it shows a speed differential between the two wheels greater than a certain amount programmed in by the engineers, it will apply the brakes on the spinning wheel which will force the power through the differential to the other wheel with traction. Basically the engineers have to allow enough speed differential for the tightest corners plus a little extra, so the difference in speed has to be significant before the BLD kicks in. Programming the system to do this smoothly and quickly is not easy, and even in a best case, it's simply not as smooth as an LSD. That said, a BLD will theoretically get you up and over something that the LSD won't, but it all depends on the particular situation and how the engineers programmed the system to work. They typically don't design such systems for tougher offroad situations and they generally don't work too well.

 

[Bubba33]

Interesting... by this logic (that the Rubicon is the only real Jeep) it would mean that from 1941-2002 were pretend Jeeps.
Rubis are great and if we had it to do over we'd get one because of how much we have come to off road our Sahara, and are now thinking of throwing a locker in the rear. But it seems on road and on forum, owning a Rubi seems to have a real attitude from some of the owners. The Jeep family modo seems to go out the window with some of them. It's as if the other models are step children.

Evidently you can't pick up on sarcasm, that's not my damn logic it's of some others that have the rubicon. I have a Sahara and why would you want lockers in the rear. Then it's just a open rear end, limited slip is way better than a open rear end on the road. I'm sure there will be some that will say I'd rather have open rear end on the snow and rain.

 

[Teghogh]

Try driving up the same hill with both vehicles in 2WD. I think the Sport will probably make it up in a fairly straight forward fashion, and while the Rubicon will probably get you up as well, it will struggle a lot more. When going uphill, the weight of the vehicle is shifted substantially to the rear wheels, so have an LSD on the rear makes a big difference. Even in 4WD it will make a substantial difference, although the difference is masked a bit by the 4WD. With the Rubicon, you'll have to wait until the BLD kicks in, and by then you've lost most (all?) of your momentum, and it's a lot tougher to get it going again. This is because of the difference in the way an LSD and BLD work.

Traditional LSDs like you can get on a Sport and Sahara kind of work the opposite way of BLD. The LSD has clutch packs connecting the two axles together; it basically operates like a locked differential until a certain amount of force is exerted to overcome the friction of the clutch pack. This breakaway force is designed to be lower than the force typically exerted on the street when going around a corner, so every time you go around a corner in the dry with an LSD the clutch pack is slipping as necessary to allow the tires to spin at different rates. When the force is lower such as when driving in snow and ice or in various situations offroad, the clutch pack exerts enough force to keep both tires turning. So an LSD works great in the majority of offroad situations.

The problem for offroading occurs when one wheel has good traction, the other wheel doesn't, and the amount of power needed to move the vehicle exceeds the amount of force needed to overcome the friction of the LSD clutch pack. This typically happens in more extreme offroad situations such as rock climbing on a steep slope with only one wheel having good traction. In this case, the engine power will overcome the clutch pack and spin the wheel with less traction while there isn't enough force being exerted by the clutch pack on the wheel with good traction to get up and over the obstacle. This is why Rubicons have true locking differentials with no clutch packs to slip.

The BLD works on a different principle. It has speed sensors on the axle, and when it shows a speed differential between the two wheels greater than a certain amount programmed in by the engineers, it will apply the brakes on the spinning wheel which will force the power through the differential to the other wheel with traction. Basically the engineers have to allow enough speed differential for the tightest corners plus a little extra, so the difference in speed has to be significant before the BLD kicks in. Programming the system to do this smoothly and quickly is not easy, and even in a best case, it's simply not as smooth as an LSD. That said, a BLD will theoretically get you up and over something that the LSD won't, but it all depends on the particular situation and how the engineers programmed the system to work. They typically don't design such systems for tougher offroad situations and they generally don't work too well.

Thanks you for the highly informative post

 

[Sean L]

It looks like your friend lost traction on diagonal wheels, and there's only so much a "Brake lock Differential" (TRACTION CONTROL) can do in that situation. Your Limited slip differential automatically prevents slippage faster than you notice you've had a slip. Its very helpful in situations like this, although when it comes to going up rocks, the lockers have the definite advantage.

 

[RubenZ]

No offense to the Rubicon Crowd but a Sport with LSD is actually a better JEEP for all around use IMO. And by that I mean, Beach running, overloading, etc. Don't get me wrong. The Lockers are great, but I'd rather have a SPORT with LSD and a Locker in the FRONT than to have the Rubicon's Open Diff Setup. Not to mention, I think the Rubi Lockers only work in 4-Lo and about 20k more LOL.

Now change my mind

 

[Sean L]

Can someone please explain BLD? We do not have lockers or LSD, just a plain M200 rear axle.

Traction control....

When you get slippage on a wheel, the brakes are applied, sending torque to the non slipping wheel.

 

[Hound Dog Lew]

No offense to the Rubicon Crowd but a Sport with LSD is actually a better JEEP for all around use IMO. And by that I mean, Beach running, overloading, etc. Don't get me wrong. The Lockers are great, but I'd rather have a SPORT with LSD and a Locker in the FRONT than to have the Rubicon's Open Diff Setup. Not to mention, I think the Rubi Lockers only work in 4-Lo and about 20k more LOL.

Now change my mind

It's a good thing you bought what you wanted then! Enjoy it.

 

[Mordin Solus]

No offense to the Rubicon Crowd but a Sport with LSD is actually a better JEEP for all around use IMO. And by that I mean, Beach running, overloading, etc. Don't get me wrong. The Lockers are great, but I'd rather have a SPORT with LSD and a Locker in the FRONT than to have the Rubicon's Open Diff Setup. Not to mention, I think the Rubi Lockers only work in 4-Lo and about 20k more LOL.

Now change my mind

Hey, if that works for you cool my first order was a 2 door Sport S with LSD. After waiting two months and building out my list of upgrades I realized all in I would be within 1-2k of. Rubicon, so went Rubicon and see no reason for upgrades for a good while.

And it’s not just the lockers, all the little things you get with the Rubicon add up. But in the end what really matters is what you want, need, and fits in your price range.

I figured I would never use the lockers for the things I wanted to do, but when put in a situation where they could be helpful I was happy to have them!

 

[kre62]

Some people are surprised to find out that a Jeep with lsd is actually better than a rubi in some situations. I know I used to have a sport with lsd and wheeled the hell out of it. And in typical situations like rain or snow the lsd is better because rubis are open in those situations.

However I got a rubi this time because I wanted the extra confidence that if I ever did get stuck I’d have a much better chance of getting out. Or if I want to take on something more challenging I can. For situations where an lsd has an advantage it does take a bit more skill to get the same result in an unlocked rubi. But lockers take it to the next level if needed.

 

[Vintage]

I love the Rubi and I know that it is hardcore better when needed. My MT, JLU Sport (LSD) with Mopar Lift and 33" Rubi takeoffs has been amazing and wheelin' is just super fun! Who knew some rock crawling was my thing? I do think my sport weighs a bit less than a Rubi and that may help in some situations. So far, I have done the Palo Duro Canyon Jeep Jamboree, Big Bend National Park, Hidden Falls northwest of Austin a couple of times, and I can't wait to do more.

It is hard to imagine what the Sport can't do in 4WL. Maybe a 2 door Rubi one day? I just wish I would have started sooner with my 2000 TJ, or my 2012 JK. I was just busy helping raise the kids and working I guess. I do like the 4 door as it is my first but miss the look of the 2 door.

 

[LincolnSixAlpha]

The whole advantage of a locker over a LSD is that when not locked it functions as a fully open differential. There are no clutch packs to wear out or other parts like a LSD that will wear out over time on the street. When engaged, a locker is superior in every way.

In follow up, the BLD is likely an "everyman" solution, requiring no intervention while, and I'm speculating here, the Rubicon's axles are open, no clutch packs, as per Offcamber's post, so nothing to wear out. However, when locked, they are two different animals, all together. Thee BLD, while "nice" would not hold a candle to the full lock of the Rubicon.

 

[JLSport92649]

If you look at my rear tires vs his, they are both equally flexed into the fender. Besides it’s it’s the front wheel that stops slipping when his locker is ingaged and in my case the BLD.
Again we have had several results in other trails as well.

Haha, tell him to buy a winch for you to pull him out next time!!

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