Great traction in bad weather

[Dog Hauler]

I just returned from a 700 mile trip, much of which was in some pretty nasty weather with lots of snow and not much in the way of snow plowing by Utah authorities. I switched bewteen4WD auto and 4WD high as conditions warranted. While I certainly had to slow down as things deteriorated, sometimes all the way down to 30 in a 65 zone, the truck was never skittish and there always seemed to be reasonable grip for the conditions. From time to time, I'd get on the brakes fairly hard to test what traction was out there and was always impressed.

The tires play a big role, of course, but the tires on the truck look to be pretty routine all weather arrangements. They're certainly not full on snows. So, while the tires deserve much credit, the 4WD drive system also deserves kudos. Regardless, the combination was quite impressive.

BTW, my reading of the manual is that the power split between front and rear wheels when in 4WD High is 50/50. Is that true and does power delivery to a given wheel vary depending on which wheels have grip?

 

[Longhorn5G]

Thats great news, and especially coming from a Utah snow testimony. I love this. Thanks!

What tires do you have and rim option? Also, did you happen to have any weight in the bed? Sorry I cant see signatures on Tapatalk, but what model overall do you have... quad or crew or what.

 

[Smoot178]

Sounds like you made the trek up traverse ridge road!

 

[Dog Hauler]

Thats great news, and especially coming from a Utah snow testimony. I love this. Thanks!

What tires do you have and rim option? Also, did you happen to have any weight in the bed? Sorry I cant see signatures on Tapatalk, but what model overall do you have... quad or crew or what.

Limited trim (by definition the longest cab...crew? I can never remember whether crew is longer than quad or vise-versa) with standard wheels/tires. No weight in the bed. Grip in really bad conditions was very impressive. But know the various drive modes and what they do. If you don't, there is no hope of selecting the right mode for the circumstance.

 

[riccnick]

There is no torque split or distribution, as this is a part time transfer case with no center differential.

 

[Dog Hauler]

There is no torque split or distribution, as this is a part time transfer case with no center differential.

Pardon my lack of sophistication when it comes to 4WD systems: Are you saying that the split is 50/50 front to back and that it remains 50/50 regardless whether one or more wheels are slipping?

 

[Electrical]

I believe that's right... remains 50/50 front/rear regardless of slippage.

If we're not talking about AntiSpin or eLocker, wheel-to-wheel slippage on the same axle is handled by the BLD function of the traction control system. Sort of an electronic limited slip differential on both front and rear. Works great imo.

Wonder if you needed 4HI. The reaction time of 4AUTO to engage the front axle should be more than quick enough to keep you glued to the road.

 

[Dog Hauler]

I believe that's right... remains 50/50 front/rear regardless of slippage.

If we're not talking about AntiSpin or eLocker, wheel-to-wheel slippage on the same axle is handled by the BLD function of the traction control system. Sort of an electronic limited slip differential on both front and rear. Works great imo.

Wonder if you needed 4HI. The reaction time of 4AUTO to engage the front axle should be more than quick enough to keep you glued to the road.

Do know about 4hi v. 4 auto. Though my thought is that if 4auto could handle it as well as 4hi, it would be a bit of a waste of time and money to put both on the car. I didn't try 4auto in the real heavy stuff so can't offer an opinion from personal experience. But next time I find myself in snow, I'll try both 4auto and 4hi to compare.

And what does my anti-spin do when 4 auto or 4 hi is engaged?

 

[Longhorn5G]

I have 4hi and lo and 4auto in my jeep. I have done some hairy stuff and never needed 4hi or lo. Auto worked fine. Plus i have the sand and rock settings, as gimmicky as they seem, to me.

BUT, i was just watching a video, today as a matter of fact, watching a 4th gen when new, out on slippery snow. One clip, he towed a trailer from stop on what looked like some slick packed snow, close to ice.

He tried 2wd. No go obviously. Then 4auto...didnt really gain much if anything. Popped in 4hi, started to pull itself and trailer and got rolling.

So, having a dedicated 4hi versus 4auto has its advantages.

 

[Longhorn5G]

4wd auto is goimg to pick and choose whichever wheel is getting the best grip. That could be any of the 4, at any differemt time. And as fast as that can be, theres still time it has to take to engage and disengage.

A 4hi, its more constant, versus a strategic hunt for grip. Its gonna spin mostly all the time.

Its like taking that traction control off in certain scenarios. I hope all this makes sense.

 

[Longhorn5G]

Anti spin is just going to stop whichever wheel is spinning.

So if you turn off anti spin or turn off traction control, it wont be trying to prevent spin where there is no grip.

If you are in 4auto, and lets say ur at the bottom of a snowy hill, trying to start from stop. If theres no traction for ANY tire, theyd want to spin. Anti slip will just shut each one down. In extreme situations, you will rev engine and NO wheel moves really.

Pop that traction control off, and you get spinning. And its that spinning that can slowly get u grip as someone pushes or u get pulled...and you turning wheel left to right.

 

[Longhorn5G]

Cant tell you how many car drivers 8n lexuses and what not i watch (and sometimes help) try to get up a hill or out if a snowed in parking spot.

Their tires either spin or wont do anything. If theyre on the road in their lexus holding ip everyone behind because theyre stu k on hill. I see the tires stop going. Its bc that traction control still on.

I go up and say, yo, turn off that traction control. They say huh what do u mean... i point to the button. They turn it off and viola, tires go, and slowly it finds grip, and they move on.

 

[devildodge]

Let's look at it like this
Note: stability and traction control do aid in this also, this is assuming that.

2wd truck open diff has one drive wheel...
with anti spin 2 drive wheels if conditions warrant the clutches to lock...
With eLocker you have two engaged drive wheels to 27 MPH.

4wd truck in 2wd same as above.

4wd in 4Hi/low. The transfer case splits power 50/50 front to rear.
Open diff you get two drive wheels, a rear and front.
Anti spin you get a front wheel and 2 rear wheels of conditions are right for clutches to lock.
eLocker one front and two engaged wheels to 27 MPH in 4 Hi and 47 MPH in 4 low.

4wd auto is a rear drive bias sending power when slippage is sent.

Ultimately with an open diff you can get power to only one wheel...hence why the guy couldn't pull out with trailer.

And you get the jist for the other 2 options.

The Rebel doesn't offer the auto at this time because the part time transfer case is more robust with a lower low low range.

 

[Electrical]

...

Ultimately with an open diff you can get power to only one wheel...hence why the guy couldn't pull out with trailer.

....

Hey DD, regarding that trailer, 2WD gave problems and 4AUTO gave problems, but 4HI did good.

Is it your opinion that 4AUTO was a problem because it relies on slippage before engaging?

 

[devildodge]

Hey DD, regarding that trailer, 2WD gave problems and 4AUTO gave problems, but 4HI did good.

Is it your opinion that 4AUTO was a problem because it relies on slippage before engaging?

My opinion...yes

 

[Electrical]

My opinion...yes

Mine too.

 

[Longhorn5G]

4Auto has a great purpose, in rain, maybe even slush. Certain gravels and loose light dirt.

But especially rain.

But when theres depth that all 4 tires are facing, it starts to become less helpful.

Just my opinion.

 

[Longhorn5G]

4Auto has a great purpose, in rain, maybe even slush. Certain gravels and loose light dirt.

But especially rain.

But when theres depth that all 4 tires are facing, it starts to become less helpful.

Just my opinion.

Forgot one: 4Auto great for DRY as well. Its just a matter of whetger or not you want to pay for it in gas. Its miniscule, but still.

4Auto, like most AWDs and Quattro types, excel at launches and holding turns.

But for anyone not real experienced with AWDs who may be reading this, remember this one thing (which seems highly counter intuitive)... if you want the 4auto to be working, you have to be using the gas. Not wide open throttle. But it needs to be told to go, in order for it to start looking for traction.

So if you're in a fast turn, and you're losing grip, our brains want to brake. In reality, one should lightly play with the accelerator, so the system can be told to find the grip.

I had been an audi quattro autocrosser at one point when much younger, yet most traction controls do the same thing, whether all 4 wheels or just 2.

I am new to RAM tho, so if this is different in some way, someone please let me know.

 

[ChadT]

Cant tell you how many car drivers 8n lexuses and what not i watch (and sometimes help) try to get up a hill or out if a snowed in parking spot.

Their tires either spin or wont do anything. If theyre on the road in their lexus holding ip everyone behind because theyre stu k on hill. I see the tires stop going. Its bc that traction control still on.

I go up and say, yo, turn off that traction control. They say huh what do u mean... i point to the button. They turn it off and viola, tires go, and slowly it finds grip, and they move on.

"I have all wheel drive!"
Points to totally bald summer tires
"No traction on those in these conditions man, sorry."

 

[ChadT]

4Auto has a great purpose, in rain, maybe even slush. Certain gravels and loose light dirt.

But especially rain.
But when theres depth that all 4 tires are facing, it starts to become less helpful.
Just my opinion.

So here's how I understand it, feel free to chime in guys I won't be offendeD!

In 2WD just the rear tires are turning.
In 4Auto, good for rain, slush, you can still turn and everything just fine, it's 2x4, and in moments where you're slipping, on comes 4x4. Those front tires come to life.
In 4high, you're "locked" (It was once called 4lock in the rams), the 4 tires are trying to turn, which also means the turning radius is impacted, binding, etc. It's why you're not supposed to engage 4high on dry pavement and try turning, the gears start to bind. In slushy slippy situations, when the outer tires have to turn faster than the inner ones - they're stuck turning at the same speed. BUT in slippery stuff, slipping can occur to protect the drivetrain.
In 4Low, you're in tank mode. All the torque you handle, keep it under 25mph-30mph I think?

The rebel's transfer case loses a 4Auto gear, but I believe it's in favor of a beefier, heavier, more robust system for the other 2 gears.
But it loses the 4Auto capability.