How 4WD Helps You Stop on Slippery Roads

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A 5 minute video when one sentence is in order. "Distribution of power" Not even a full sentence.
 
Yeah, but it only works with real locked 4WD. So it does not apply to these new fangled AWD crossover whatama doo hickeys with lane assist, auto parking, self braking and bluetooth texting so you can keep your eyes on your phone where they belong.
 
Thanks for sharing that. I found it pretty interesting.

TL;DR--2WD breaks mainly the front tires, while the rear tires keep moving the car forward. 4WD distributes the breaking power more evenly among the front and back tires, allowing it to stop sooner.

Did I summarize that correctly?
 
Originally Posted By: paulri
Thanks for sharing that. I found it pretty interesting.

TL;DR--2WD breaks mainly the front tires, while the rear tires keep moving the car forward. 4WD distributes the breaking power more evenly among the front and back tires, allowing it to stop sooner.

Did I summarize that correctly?

"4WD brakes driven wheels."
 
Originally Posted By: eyeofthetiger
Yeah, but it only works with real locked 4WD. So it does not apply to these new fangled AWD crossover whatama doo hickeys with lane assist, auto parking, self braking and bluetooth texting so you can keep your eyes on your phone where they belong.

Some of the crossovers do have a selectable centre diff lock but often that shuts off at hwy speed.
When my wife first switched from our 03 MT 4x4 Tracker to the AT AWD CRV , the poor braking in snow was the first thing she noticed. One front tire or the other on the CRV would lock up and get the ABS going and you actually have to press the brakes harder to get the other 3 tires to use their full grip. The Tracker with no ABS essentially slowed all 4 tires equally when in 4wd and slowed the tires at a reasonable rate as the engine is also locked to wheel speed with the MT. She ran the Tracker in 4wd with any amount of snow on the road, or even if the road was wet and the system didn't seem to mind being in 4hi for 10's of thousands of hwy miles in the winter.
 
Originally Posted By: IndyIan
Originally Posted By: eyeofthetiger
Yeah, but it only works with real locked 4WD. So it does not apply to these new fangled AWD crossover whatama doo hickeys with lane assist, auto parking, self braking and bluetooth texting so you can keep your eyes on your phone where they belong.

Some of the crossovers do have a selectable centre diff lock but often that shuts off at hwy speed.
When my wife first switched from our 03 MT 4x4 Tracker to the AT AWD CRV , the poor braking in snow was the first thing she noticed. One front tire or the other on the CRV would lock up and get the ABS going and you actually have to press the brakes harder to get the other 3 tires to use their full grip. The Tracker with no ABS essentially slowed all 4 tires equally when in 4wd and slowed the tires at a reasonable rate as the engine is also locked to wheel speed with the MT. She ran the Tracker in 4wd with any amount of snow on the road, or even if the road was wet and the system didn't seem to mind being in 4hi for 10's of thousands of hwy miles in the winter.


Oh yeah, The CR-V has Honda's "Real-Time 4WD". I had an Element with the same thing. It only engages the rear wheels under throttle, and only when the front wheels slip enough. I had an Element with the same system. It was certainly better than FWD, but is very mild as far as AWD goes. I think the Pilot and some other Hondas have lockable center differentials that work at low speeds. It should have been an option on the CR-V and Element, too.

In fact, I am reminded of my mother recently complaining about her AWD Ford Escape being hard to control when trying to get down her steep driveway in the winter. Even with winter tires, the Escape just can't get down the driveway without sliding all over. She used to have an Expedition, and she would lock it in 4-Low to creep down the driveway with no problem, despite using regular all-season tires. She only got rid of it because it was too big and thirsty. She recently asked me about what new compact or mid-sized SUVs were available with better 4WD systems for her driveway. I had to tell her that there weren't too many left on the market. The Toyota 4-Runner was the only one I could think of with real 4WD and a low range.
 
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That or a Cherokee/Renegade/Compass Trailhawk. Although first gear in the 9 speed trans is so low it almost feels like a low range.
 
Originally Posted By: DemoFly
Originally Posted By: paulri
Thanks for sharing that. I found it pretty interesting.

TL;DR--2WD breaks mainly the front tires, while the rear tires keep moving the car forward. 4WD distributes the breaking power more evenly among the front and back tires, allowing it to stop sooner.

Did I summarize that correctly?

"4WD brakes driven wheels."


Puzzled. Y'all are talking about engine braking, presumably, but I thought y'll drove automatics, which (on my only automatic so far, 2 RWD), gives you very little. Is it specially enhanced in 4WD?

Only driven manual 4WD (Daihatsu 4-track) and never on bad ice, though in snow a bit.

With 2WD on ice, (or any other time, really) didn't use engine braking much. I coast a lot, and I use the brakes to stop the car, because I think that's what they are for, and because they operate on all wheels. I also prefer RWD to FWD generally, and especially when its slippery. .

Expert drivers tell me this is all wrong.

Dunno, but I do know that I've had FWD cars swap ends a couple of times when I accidentally used engine braking in slippery conditions
 
Yeah, if you dump it in Reverse and floor it
grin2.gif


But seriously, that Cherokee doesn't have ABS. Neither does mine, when stopping on a loose gravel road in a hurry in my Jeep, sometimes you have to shake out your shorts. Actually last month I was in traffic in it and cars in front of me stopped real quick, I was going maybe 30 mph and slammed on the brakes, the fronts locked up and I was surrounded with white smoke from the tires, it just kept skidding and I stopped in time.
 
My Montero has slid over black ice on trails (Engineer's Pass out of Silverton,CO) I could hear the ice cracking and of course sliding. I carefully backed down, very very slowly. 4x4 backwards in adverse conditions is always fun.

I recall, at Mt. Rainer (Paradise) down hill, no type of 4x4 system can mitigate ice and physics. Not even a Hummer or 6x6 will fair better. Heavy vehicles tend to slide faster (down hill). I learned that in my Montero.

As the previous poster indicated, tires are what matters. Airing down tires helps a lot. Friction is your friend. Helps in ice, snow, and sand.

I have a rear locker, but meaningless in ice.

For many many reasons; I shouldn't be alive......


Respectfully,

Pajero!
 
Those drivers at o neill know way more about driving then we could dream about.

I have observed the same thing when I owned a primitive 4wd with power locked together on mud and snow. AWD remember is different and varies amongst car makers. My wife had a full time 45/55 split pure mechanical bliss with LSD rear on her 2005 Subaru Legacy turbo wagon 5mt. She prefers the feeling of control over a modern nanny AWD car like our Acura on snow/ice.
 
Originally Posted By: Nick1994
Yeah, if you dump it in Reverse and floor it
grin2.gif


But seriously, that Cherokee doesn't have ABS. Neither does mine, when stopping on a loose gravel road in a hurry in my Jeep, sometimes you have to shake out your shorts. Actually last month I was in traffic in it and cars in front of me stopped real quick, I was going maybe 30 mph and slammed on the brakes, the fronts locked up and I was surrounded with white smoke from the tires, it just kept skidding and I stopped in time.


ABS defeats slowing you down in these conditions and gravel.
 
Originally Posted By: andrewp1998
Tires matter more than anything IMO..


Yes but if you have primitive 4wd and some AWD like the video vehicle stopping power is better and evenly distributed with winter tires.

Some AWD because certain (most) systems remain FWD until traction required on rear.
 
I have good luck on wet ice with 4 low, but that wouldn't be good for a race like what's in the video.

9.9 times out of 10, I won't be going fast enough on nasty conditions for this video's purpose to make any sense.

That said, who wouldn't be in 4WD with these conditions anyways?
 
Originally Posted By: Pajero
Let's see that on ice!





Respectfully,

Pajero!


X2. It wouldn't make one bit of difference.

I honestly think selecting a lower gear has more to do with this than anything. If one were creeping along in low or had to put there vehicle in low quickly in snowy conditions, I think, whether 4x4 or not, would have the same effect. Like what has been mentioned, snow tires and good brakes are the 2 most important factors.
 
I have driven on freezing rain (ICE) and the front wheels skid very easily, and locking up the wheels did help prevent sliding with braking and traction. This was pre-ABS and with A/T. Both diffs were open (not posi or a locker)
 
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