4 Wheel drive on icy roads question
CharlesW99
Hi! We are shopping for a pickup truck and as we live in the hills, we
were interested in a 4 X 4 (in past winters, we have had to chain up our
sedans simply to get up the road to our home). One salesman indicated that
4 X 4s were only good when there was something for all the wheels to "push
against", and in compact, icy snow conditions the front wheels might turn
faster than the rear wheels and if you drive this way a lot, you could
damage the transfer case, especially if you were running in 4 wheel on
just wet asphalt. He said that 4 X 4s were best in the dirt, or mud, or in
snow. He suggested that a rear wheel drive with limited slip with lots of
weight in the back should be a better choice for us as we do not do
extreme driving.
Well, I know in past winters, virtually the only vehicles going up our
road when there is compacted snow without chains are 4 wheel drive
vehicles. I have also seen in freezing rain conditions that some 4
wheelers chain up just the front wheels; is there some sense to this?
Regards,
Charlie charl...@aol.com
Dogs' Life
CharlesW99 wrote:
>
> Hi! We are shopping for a pickup truck and as we live in the hills, we
> were interested in a 4 X 4
<snip> Charlie - no 4x4 is a substitute for good, safe driving. And no
4x4 is going to handle icy conditions without some trouble. This is
especially true for vehicles with a markedly uneven weight distribution,
like pickups. If you get a pickup, you can diminish this problem by
loading up the back with weight. Around here, folks usually use mud
buckets full of sand. That way you get the extra weight, plus sand for
traction if the conditions really stink.
You didn't mention your reason for wanting a pickup. Have you considered
a Subaru, or one of the mini-utes like the RAV4? These aren't off road
machines, but for most people they do a great job. Personally, I'd lean
toward the Subaru. I've never seen one get stuck, although the older
models seem to self-destruct from rust rather quickly.
I really want to emphasize safe driving, though. We live on a hillside
next to a major ski resort in Northern New England, so you *know* we see
a lot of snow and ice. We drive Pathfinders with studded snow tires in
winter (Yokohama SDO-Vs in mud, bug and foliage seasons) and live at the
end of a very steep road with a spring at the top. The last 50 feet or
so is solid ice, as is the paved road below about two weeks each year.
We've never been stuck, though we've pulled a lot of hotshots in
4Runners and Jeeps, families in Explorers, and locals in Fords or Chevys
out of snow banks each winter. It's not that our Pathfinders are any
better in winter conditions; it's that we drive appropriately for the
conditions. Whatever you get, practice, practice, practice.
<snip>
>
> Well, I know in past winters, virtually the only vehicles going up our
> road when there is compacted snow without chains are 4 wheel drive
> vehicles. I have also seen in freezing rain conditions that some 4
> wheelers chain up just the front wheels; is there some sense to this?
>
I've seen this too. Makes sense for FWD. The one person I asked said he
put them on front of his Jeep because that was where 60% of the weight
was distributed. Just a guess, though. I've never used chains. Studs and
finesse work fine for me.
Pete
North Central Vermont
87 Pathfinder: 333,000 troublefree miles in mud and snow
92 Pathfinder: 54,000 troublefree miles in mud and snow
93 Civic: spends 7 months of mud and snow tucked safely in the garage
Doccers
In article <19970727064...@ladder01.news.aol.com>,
charl...@aol.com (CharlesW99) wrote:
>Hi! We are shopping for a pickup truck and as we live in the hills, we
>were interested in a 4 X 4 (in past winters, we have had to chain up our
>sedans simply to get up the road to our home). One salesman indicated that
>4 X 4s were only good when there was something for all the wheels to "push
>against", and in compact, icy snow conditions the front wheels might turn
>faster than the rear wheels and if you drive this way a lot, you could
>damage the transfer case, especially if you were running in 4 wheel on
>just wet asphalt. He said that 4 X 4s were best in the dirt, or mud, or in
>snow. He suggested that a rear wheel drive with limited slip with lots of
>weight in the back should be a better choice for us as we do not do
>extreme driving.
>
>Well, I know in past winters, virtually the only vehicles going up our
>road when there is compacted snow without chains are 4 wheel drive
>vehicles. I have also seen in freezing rain conditions that some 4
>wheelers chain up just the front wheels; is there some sense to this?
>
>
>Regards,
>
>Charlie charl...@aol.com
Considering that most 4wd systems involve locking the front and rear axles
together, the front wheels can't spin faster than the rear. If the 4wd
system has a "Full time" mode, this won't damage it anyways.
Dave Burr
CharlesW99 wrote:
>
> Hi! We are shopping for a pickup truck and as we live in the hills, we
> were interested in a 4 X 4 (in past winters, we have had to chain up our
> sedans simply to get up the road to our home). One salesman indicated that
> 4 X 4s were only good when there was something for all the wheels to "push
> against", and in compact, icy snow conditions the front wheels might turn
> faster than the rear wheels and if you drive this way a lot, you could
> damage the transfer case, especially if you were running in 4 wheel on
> just wet asphalt. He said that 4 X 4s were best in the dirt, or mud, or in
> snow. He suggested that a rear wheel drive with limited slip with lots of
> weight in the back should be a better choice for us as we do not do
> extreme driving.
>
> Well, I know in past winters, virtually the only vehicles going up our
> road when there is compacted snow without chains are 4 wheel drive
> vehicles. I have also seen in freezing rain conditions that some 4
> wheelers chain up just the front wheels; is there some sense to this?
>
> Regards,
>
> Charlie charl...@aol.com
Four-wheel drive comes in more than one flavor. If your 4WD is
designated as "full time", there is a differential or viscous coupling
in the transfer case to handle the difference in necessary *driveshaft*
speed betwen the front and rear driveshafts. If you do not have *full
time* four, when you engage 4WD, both the front and rear driveshafts
will turn at the same speed so you will indeed be hard on the drivetrain
and tires on all but the most slippery surfaces.
Full time 4WD is indeed desirable for most slippery conditions. Unless
you have a limited slip or locking differential in the front or rear,
just remember that if you get into a problem(stuck), you can spin one
wheel while the other three just sit there. Under part time four, at
least two wheels will be working (spinning or moving the vehicle).
Limited slip diffs would be desirable on one or both axles. *Locking*
diffs are not desirable except for offroad use (where they are great).
For street driving on slippery surfaces like snow, locking diffs will
have a tendency to break BOTH the wheels on the axle loose, whereas you
really need to keep one from breaking loose to maintain directional
control, so choose a limited slip or a standard open differential.
Don't listen to car salesman. If they were engineers or highly trained,
experienced mechanics, something tells me that they wouldn't be be car
salesman.
Dave
Chopper
CharlesW99 wrote:
>
<SNIP>
>One salesman indicated that
> 4 X 4s were only good when there was something for all the wheels to "push
> against", and in compact, icy snow conditions the front wheels might turn
> faster than the rear wheels and if you drive this way a lot, you could
> damage the transfer case, especially if you were running in 4 wheel on
> just wet asphalt.
>
>
> Charlie charl...@aol.com
The salesman is an idiot.
A typical transfer case (in a real 4x4) has 2Hi-4Hi-4Lo. Some older
cases have 4hi-4hiLok-4Lo-4LoLok. In either case, standard 4Hi selection
sends power to both axles in a percentage split of torque, many can
adjust to traction and load conditions. Only in Lo or Lok positions are
the axles "locked" together in a 50/50 split of power.
Most of the AWD or full time 4wd systems employ a viscous coupling (auto
tans) to transfer different amounts of torque to each axle and most will
also vary this depending on conditions/tire slippage. You cannot damage
a system like this or any other 4x4 system in the conditions you
describe.
Most part-time pickup 4x4 systems are designed to be used under
conditions of loose surface use only - snow, ice, mud, sand. While
driving over short stretches of dry or wet pavement in a straight line
will not damage the system (unless maybe you're in low-lok), extended
driving like this will.
Research your options carefully. Jeep puts several different kinds of
4wd systems on the Cherokee and Jeep depending on the model & trim level
and they all work differently.
Subaru uses viscous coupling on auto trans models and a conventional(?)
full-time t-case on stick models. Subaru's go like snowmobiles in most
any condition. I've never been able to get one stuck unless it was
high-sided in deep snow or a snow bank.
Many so-called "manually" operated 4wd systems, like those used in Chevy
trucks (spit), use solenoids, electrically or thermally operated
plungers, auto-hubs, etc. to engage the front axle and can fail to work
under extreme cold and other conditions. Ford Ranger/Explorer auto-hubs
grenade quite frequently and cost about $200 each. Many models offer
manual hubs at no charge or even a credit.
Limited slip is great for pulling, mudding and deep snow running but can
be dangerous on very slick surfaces like ice if you don't treat it
right. LSD, because it will turn BOTH wheels can cause you to loose
traction and slide the rear end off the crown of the road.
Whatever you get Read The Manual or seek help from someone who REALLY
knows how the system works - salesman suck.
Chopper
Doug Filer
Hi Charles :)
Well, what the salesman says about driving 4x4's on icy snow possibly
causing damage to the transfer case is news to me. Driving on icy roads
is a lot different than driving on wet pavement.
I live in an area that invariably gets from 3" to 5" of freezing rain
each year.... several times and lasts about a week each time. This
tends to not be as 'black ice', but a bit more lumpy due to the wind and
sleet. There is a very steep (guesstimate at 15 degrees) blacktop road
about a quarter mile long that I must drive under these conditions, as
well as the other roads to get to town. After doing this for better
than12 years with different 4x4's (85 S10, and at present a 79 GMC), I
can say that I have never chained up, and haven't needed to (I use
non-studded BFG Mud T/A's). However, neither has my CRX with studs
(front and rear tires because of wind). Now black ice is a different
matter altogether. That's usually not very thick, and I think studs
would be best.
Starting and moving forward on ice isn't the problem, it's stopping that
is! I've noticed that the 4x4 does stop a bit better on icy conditions,
simply because there are (in my case) three wheels providing engine
resistance. When going down the hill during the icy conditions, I
typically put the truck in low range, and crawl. Once the brakes lock
up, its like a toboggan.
As far as putting lots of weight in the bed of a truck in icy
conditions, It would help I imagine, but I haven't had to do it.
Hope I was able to help a little!
CharlesW99 wrote:
> Hi! We are shopping for a pickup truck and as we live in the hills, we
>
> were interested in a 4 X 4 (in past winters, we have had to chain up
> our
> sedans simply to get up the road to our home). One salesman indicated
> that
> 4 X 4s were only good when there was something for all the wheels to
> "push
> against", and in compact, icy snow conditions the front wheels might
> turn
> faster than the rear wheels and if you drive this way a lot, you could
>
> damage the transfer case, especially if you were running in 4 wheel on
>
Janice Lilienthal
I`m from Minnesota.(I know all about snow and ice!) The best thing I`ve
found is front wheel drive. Preferably with wider tires.
Cybor Willy and Webmiester Jan
Rich Rubel
Chopper (Rterry@NO_SPAM_Earthnet.net) wrote:
: Subaru uses viscous coupling on auto trans models and a conventional(?)
: full-time t-case on stick models. Subaru's go like snowmobiles in most
Viscous coupling on manual trans and computer-controlled clutches on auto
models. Older models have a conventional part-time 4WD system; some older
PT and AWD also available with dual-range, LSD, and locking center diffs.
Wish they'd bring those back :-(
--
+--------------------+---------------------------------------------------+
| Rich Rubel | Happiness is an AWD Subaru! |
| rru...@umbc.edu | Turn a SNOW problem into NO problem. |
| | http://alumni.umbc.edu/~rrubel1/outback.html |
+--------------------+---------------------------------------------------+
Chopper
Rich Rubel wrote:
>
> Chopper (Rterry@NO_SPAM_Earthnet.net) wrote:
>
> : Subaru uses viscous coupling on auto trans models and a conventional(?)
> : full-time t-case on stick models. Subaru's go like snowmobiles in most
>
> Viscous coupling on manual trans and computer-controlled clutches on auto
> models. Older models have a conventional part-time 4WD system; some older
> PT and AWD also available with dual-range, LSD, and locking center diffs.
> Wish they'd bring those back :-(
<SNIP>
You're right, duh that's what I meant to say - you'd think I could get
it right since I've owned all types. :-)
Chopper
--
RT
MSCS, Inc.
IBM Industry Remarketer
Authorized Network Integration IR
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*--------------------------------------------------------------*
* This post is relavent to ONLY the related requested *
* information and is in no way meant to indicate these *
* are the only solutions to any given problem. While *
* accurate points of fact (including references, if *
* available) for mis-information are welcome, flames *
* for opinion are not and will be appropriatley ignored. *
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Rich Rubel
Chopper (Rterry@NO_SPAM_Earthnet.net) wrote:
: You're right, duh that's what I meant to say - you'd think I could get
: it right since I've owned all types. :-)
You were just checking if we were awake, right?
Paul W Harvey
On Sun, 27 Jul 1997 14:29:30 GMT, Doccers <supe...@ix.netcom.com>
wrote:
>
>>Well, I know in past winters, virtually the only vehicles going up our
>>road when there is compacted snow without chains are 4 wheel drive
>>vehicles. I have also seen in freezing rain conditions that some 4
>>wheelers chain up just the front wheels; is there some sense to this?
Yes, there is *some* sense in chaing the front if your worried about
going (not stopping). It's the same reason why front wheel drives
ususally get better tracion than rear, almost every car on the road is
weight biased toward the front. If you chain the front they will dig
in more and give you more tracion.
You have to be *very* careful with this though. Some trucks (mine)
won't take chains in the front - not enough clearance between the
fender and the tire. If I chained my front I'd rip the fenders to
shreds.
As for adding weight, yes it does help - a bunch. I lived in snow
country (AK) for a few years with a 2wd Nissan. I went *nowhere*
without wiehgt in the back, even with studs on all four. After I
thrrough about 300# of crap in the back the little thing was a tank.
Darn near drove through everything.
Had similar experience with my F-150 up there too. In snow and ice
with ATs the truck drives okay without weight in the bed. Through
about 500#s of crap in the bed and you almost don't realize there is
any problem. The thing becomes unstoppable, literally.
Of course this was the downside too. Having that extra mass to stop
is very noticable, at the worst times. Because of this I only put a
lot of weight in the bed when absolutely necessary. I couldn't get
going as quickly, but that kept remending me that I shouldn't being
going that quickly anyway.
--Paul
ke...@aquilagroup.com
> Yes, there is *some* sense in chaing the front if your worried about
> going (not stopping). It's the same reason why front wheel drives
> ususally get better tracion than rear, almost every car on the road is
> weight biased toward the front. If you chain the front they will dig
> in more and give you more tracion.
>
> You have to be *very* careful with this though.
Hear hear! Last winter I was commuting between girlfriend's house in
moutains (such as they are) to town. Ice one place, dry pavement the
other. Since I have the chains, I figure use them...same reason I fly
with parchute....better to wear it and not need it than vice -versa.
Anyway, chaining up everyday for a week, I experimented with several
configurations. By far the best setup was with cross-bar chains on the
rear and cable chains on the front. This setup gives lots of traction
stopping & starting, tends to stay straight with agressive stopping and
will understeer if you take a corner too fast. The cable chains have a
little less bite than the "real man" chains in the rear, and that gives a
traction bias that keeps truck from wanting to spin out. The cable
chains also don't require much fender clearance and go on and off real
easy. I do have two sets of "real" chains in case it gets real bad...deep
snow or mud, but always worry about wrapping up front bake lines, and the
heavier chans WILL drag the frame rails at steering lock.
Since the rear is light anyway, chaining up only the front gives a huge
traction advantage to that end. Thats fine when starting out, but this
makes the rear want to pass the front when stopping or
cornering.....SEVERE oversteer. It was a WILD ride, and I'll never try
that again. Configured in this way, the truck was much _less_ controlable
than with no chains at all.
Chaining only the rear worked OK, but the the good stopping and ability
to "horse" it around corners when it wanted to keep going straight made
chaining the front well worth the effort. Remember, it is as important to
keep control, and be able to move out of danger's way, as it is to be
able to "go". Being a Denver kid, I coulda "gone" in 2WD in those
conditions, no problem, but 4WD and chains gave a huge margin of safety.
On the trail, If you have only one set of chains, and you only want to
creep anyway, chaining the front may be useful. But it can seriously
degrade controlability in "street" conditions. For street conditions,
chain rear or all IMO.
In fact, chaining up all four might save the person who started this
thread the expense of buying a 4WD at all. All the stopping ability, and
most of the starting & cornering should be there if this were done to any
2WD car....might even turn as well if it was FWD. In fact, I got up
first morning at 4:30 to chain up so I could get to work at 6:30....real
cold, took a couple three breakes to warm hands before 4 chains were
on...after all that I forgot to lock in front hubs! It still went,
stopped, and handled real nice. Much better and safer than 4WD
sans-chains in those conditions. Mental note: Make coffee before putting
on chains!
General observations on driving 4WD on slick roads: 4WD handles ice
similar to FWD...you can use power to pull around corners without loosing
rear end like RWD does. RWD training will rarely get you in
trouble...the one exception I've found is that it IS possible to lose
traction on all four when engine braking....be ready on the clutch.
Engine braking is real handy with RWD, as the front will keep rolling and
steering even if you lose the back, but it is not so great with 4WD.
Finally a question for the group: Anybody know a clean way to add "po'
man's locker" i.e. independantly operable parking brakes? Just ask anyone
who ever drove a tractor.....REAL handy for getting unstuck..just brake
the spinning wheel and pull out with the one that has traction.
-Kevin
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hitman
I believe when the hubs are locked and you're in 4 wheel drive, all
whells turn the same. That's why you don't drive on hard pavement
locked and in 4 wheel. Because on a turn the tires wear themselves
badly.
Ron
On 27 Jul 1997 06:44:06 GMT, charl...@aol.com (CharlesW99) wrote:
>Hi! We are shopping for a pickup truck and as we live in the hills, we
>were interested in a 4 X 4 (in past winters, we have had to chain up our
>sedans simply to get up the road to our home). One salesman indicated that
>4 X 4s were only good when there was something for all the wheels to "push
>against", and in compact, icy snow conditions the front wheels might turn
>faster than the rear wheels and if you drive this way a lot, you could
>damage the transfer case, especially if you were running in 4 wheel on
>just wet asphalt. He said that 4 X 4s were best in the dirt, or mud, or in
>snow. He suggested that a rear wheel drive with limited slip with lots of
>weight in the back should be a better choice for us as we do not do
>extreme driving.
>
>Well, I know in past winters, virtually the only vehicles going up our
>road when there is compacted snow without chains are 4 wheel drive
>vehicles. I have also seen in freezing rain conditions that some 4
>wheelers chain up just the front wheels; is there some sense to this?
>
>
>Regards,
>
>Charlie charl...@aol.com
Sebastian Fl (originally NJ, toms River, Neptune, Maplewood, Brick