Jeep Wrangler Forum banner
  • Hey everyone! Enter your ride HERE to be a part of January's Ride of the Month Challenge!
1 - 11 of 11 Posts

·
Registered
Joined
·
7,723 Posts
Again, I reiterate: I understand the need for regearing to compensate for lost onroad performance, or to improve it with stock tireswhen towing and/or for high altitude driving, this is not what I'm asking about. I do not understand (perhaps yet) the argument regearing is necessary for offroad performance. I remain open minded about this, and I may very well be wrong.
Speed (or lack of) and torque.
With such an incredible amount of torque at such a slow forward crawling speed.... a tremendous amount of finite and detailed control becomes available.

I have the rubi, (4:1 tcase) with auto tranny and 5.13 gears. Forward speed at idle (1st gear on the tranny) is about 0.4 to 0.5mph (average walking speed is about 3mph)... but try hard as you can to stop the dammed jeep! I need two feet on the brake pedal to hold it at a stop. It just WANTS to climb. I can go up and over a LARGE 3 foot rock without touching the gas at all... and not only does the wheel climb up and over, but it also drops down over the rock at the same slow speed it went up. I don't have to gun the gas to get it to climb and risk over shooting and flying off the other side of the rock. It "climbs" down with the same control it climbed up.

I use 4lo to pull my boat out of the water. No engine revving, no gas pedal gunning... I just take my feet off the brake and the engine idles a 5000lb boat out of the water.

4lo (with gearing) is about absolute total control over a rather huge amount of torque
 

·
Registered
Joined
·
7,723 Posts
I have found it depends on what type of wheeling you are doing. It also depends on how much torque your engine provides. I have a buddy with a 4 liter TJ and a rubi case 4.88s and a manual trans and 35s. He can rock crawl fine BUT get him in sand or mud (like we have here in Wisconsin) and he struggles. Another buddy with a TJ, rubi case,35s, 4.88s and auto BUT has a LS engine.
I think that probably has more to do with the auto vs manual tranny. Autos are better at transmitting uninterrupted power to the wheels, even when they are shifting. That's needed in the mud, sand, and snow. Because of the clutching required on manuals, more often than not you have an on/off power curve to the wheels.
 

·
Registered
Joined
·
7,723 Posts
and I am going to pick on @Bob Sanders here.
Well, I'm just thoroughly incensed and insulted! :)

Actually what I need is the bigger brake rotors. When the stock rotors die I will upgrade, but until then... neutral works fine too.

True... you can feather it out with a manual and a clutch.... but too much of that and you end up replacing clutches prematurely.
 

·
Registered
Joined
·
7,723 Posts
Of course I was not bad mouthing ya, just that to much gear and the torque multiplication you get with an auto can cause an issue. I am having to look at this because I will be moving to an auto whenever I pull the trigger on the V8, provided the state does not get in the way.
The big brake kit is a good idea if you're going to regear... particularly with a v8 and/or 4:1 tcase. At some point though the size of the brakes won't matter. You get enough torque going and even the best brakes just won't hold you back, and that's when shifting in/out of neutral comes into play. It's not a huge issue... you just have to remember to have your foot on the brake when you do hit neutral.

I was watching a video of a guy with a 4 speed atlas. Of course he had a manual so he could feather the clutch out at any time, but just as a point of demonstration even with big brakes, he stuck it in low 4wd, and couldn't hold it back with 2 feet jammed hard on the pedal.
 

·
Registered
Joined
·
7,723 Posts
I'm thinkin when you have so much torque your stock brakes won't stop you, you've overdone it.

What is the benefit of that? Being able to navigate any obstacle without touching the gas pedal? I mean a lesser amount of torque will do if you drive an automatic. It will not stall on you.
Well, I didn't say it won't stop. Those are your words, not mine. I said I need two feet on the pedal to hold it at a stop.
That's not at all the same as "....stock brakes won't stop you"

But yes, as already stated I should be using the big brakes. I simply refuse to throw good rotors into the garbage can. There is no sense in that. I will go with big brakes when the stock rotors and pads bite the dust.
 

·
Registered
Joined
·
7,723 Posts
you've overdone it.
Interesting... I was reading up on that... I haven't done it enough :)

My crawl ratio is around 92:1

According to this article below, 100:1 is what most in the real rock crawling world strive for.

The 100:1 range is about what most strive for in a rockcrawling rig. You can certainly get away with a much higher (numerically lower) crawl ratio, but the lower you go, the greater the odds of not having to back out of any obstacles on the trail.
 

·
Registered
Joined
·
7,723 Posts
You, of course, arrange your rig as you please, from my point of view that does however seem strange. Two feet on the pedal does translate to one heck of a press, for me that would be more than 200 lbs of pressure and I'm no strongman. Better be careful, the back of the seat migh give in 😃
Well, you're kind of thinking in one world while talking about another.

The crawl ratio of your average 3.21 sport in 4lo is pretty bad. It's like 40:1 I think.
At that ratio you will need to rely pretty heavily on the gas and brakes while crawling over a large rock. You will have to gun it to get it up, and provided you don't overshoot the other side of the rock and launch your front end into space for a second or so, and you will have to brake pretty hard while coming down the other side to remain in control (probably two feet on the brake)

The question you SHOULD be asking is how often do you actually need to use the brakes at a crawl ratio of 90 or 100 to 1 (in my case roughly 0.5mph). I can crawl over that same rock without touching the gas.... OR.... the brakes. Unlike the 3.21 sport above, it CLIMBS down. It doesn't drop down.
 

·
Registered
Joined
·
7,723 Posts
I don't know what this guy's crawl speed is but it's an atlas 4 speed and it goes up and over effortlessly with no gas... and it looks like no brakes either. The question I have is how much gas gunning and braking would you have to do if you had the crawl ratio of a stock sport.

 

·
Registered
Joined
·
7,723 Posts
I for one have enough fine motor skills to modulate gas and brake with more range than "gun or step on it". I get what you are pointing at here, but the the option for high crawl ratio is not wreckless use of pedals.
Well... we're talking ONE rock as a point of example. Put a dozen or 2 in front of you......

I have the (slight) benefit of having the optional 3.73 gear ratio, dunno how "bad" the stock 3.21 is.
3.73 on a sport isn't much better. 3.21 comes out to 40 crawl ratio while 3.73 comes out to 44. Meanwhile the above article is calling 50:1 "reasonable" and 100:1 is what "most strive for".

Not saying that you can't crawl in a stock sport. You sure can.... at least on some of the more moderate trails anyway... but the point is the bigger the crawl ratio (within reason), the more torque and control you will have.

Now that being said, I don't really do rock crawling, but that doesn't mean I don't need it and use it. Just getting my boat into a very narrow road and driveway... well... put it this way... a truck or stock sport would be a disaster.
With the 4:1 Tcase and 5.31 gears, I climbed up and over that rock in front effortlessly in an area where I needed some serious control.

How do you get a 35 foot boat trailer to make pretty much a 90 degree turn on a dirt road no wider than a jeep?
You go OFF road of course :)

Tire Wheel Plant Land vehicle Vehicle

Wheel Tire Plant Car Plant community

Tire Wheel Plant Watercraft Vehicle
 

·
Registered
Joined
·
7,723 Posts
To reiterate my point, I lose grip before I run out of torque, and with auto tranny there's no risk of stalling the engine in any situation.
You can have the best 4 wheeler in the world and it's still a big ZERO without grip....but that's an entirely different ball game and there are other ways to combat that.... lockers.... bigger wheels with more aggressive rubber.... airing down, yadda yadda.

But yeah... we're in snow up here 6 or 7 months of the year and I rarely ever use 4lo in the snow. There is no sense in it because there is simply not enough grip even with lockers to support 4lo. So there are some situations where 4lo is totally useless... but you are not using 4lo to increase grip. You are using 4 lo for increased torque at a lower speed for more precise control, and my best guess between your crawl ratio and mine is that you will be using brakes and gas a heck of a lot more that I will have to, to make up for the lack of control that you have.

Like that article I posted above says:

The 100:1 range is about what most strive for in a rockcrawling rig. You can certainly get away with a much higher (numerically lower) crawl ratio, but the lower you go, the greater the odds of not having to back out of any obstacles on the trail.
 
1 - 11 of 11 Posts
Top