highway speed in full time 4X4?

Depends on the vehicle and also whether or not your definition of "safe" includes such hazards as speeding tickets.

e.g. the Porsche Cayenne Turbo will hit 160 mph easy, and has a suspension that can keep it between the white lines at that speed.

On the other hand, in a traditional 4x4 without ride height control, I'll be darned if I'll risk much over 80 mph.

I think the real question is not what is the max safe speed, but rather what speed would you want to go in 4WD? The problem being that connecting all of that stuff to the engine costs lots of gas, and if you can go so fast as to be concerned that you are hurting anything, I think you should be wondering if you can get better mileage at that speed if you shifted into 2WD.

I figure if I'm in 4wd, 55mph is plenty fast. That's as fast as I'll go, if i find the need to use 4wd, and the conditions are right.

I'm not sure where you are going with this, but my wife drives her AWD Astro at 80+ mph on the interstate.

-- JimG

80' CJ-7 258 CID 35" BFG MT on 15x10 Centerlines D44 Rear, Dana 30 Front. SOA 4.56 Gears, LockRight F&R Dana 300 w/4:1 & Currie twin sticks Warn X8000i w/ dual batteries

I run up in the 60 mph's using part time 4x4 depending on conditions.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Barry Bean wrote:

"L0nD0t.$t0we11" wrote in news:1pmKb.230834$8y1.985290@attbi_s52:

Let me be more specific-

If I'm driving my Jeep Liberty on the interstate in bad weather (i.e. drizzle near freezing, light snow, patchy snow), is it safe to use "full time 4X4" at speeds of 55-75? The manual says I can safely shit in or out of 4wd at up to 55 mph, but makes no mention of a top speed, automatic disengage speed, or other limit on 4X4 at highway speed.

55-75+ mph should be no problem in your Libby.

Always a good idea.

This is probably because the manual mistakenly assumes something resembling self-preservation instincts on the part of the driver.

A full time 4wd can be left engaged at any speed, as it has the slippage needed. HOWEVER this does not mean it is anything less than insanely reckless, homicidal, and suicidal to actually drive at high speeds under degraded weather conditions.

A full time 4x4 doesn't disengage at any speed. That is a part time 4x4 mode which should never be used on a highway unless it is extremely slippery...enough to keep the driveline from binding up. And if the highway is slippery enough to need part time 4x4, 55 mph is insane.

On patchy snow? Please post your driving area and the color of your vehicle so I can avoid you like the plague.

I ain't drive'n no Libby in patchy snow!

I'll be the one in the black Fiero going by you at 70 on snow covered I-77 !

We ain't afraid of no snow here in the hills! :-)

JimG

"L0nD0t.$t0we11" wrote in news:2BDKb.144057$VB2.547466@attbi_s51:

Please. Its not unusual to drive in conditions that allow traffic to flow at the speed limit, but at the same time warrant extra attention or efforts to maintain control.

Thanks, that's helpful. Nothing furthers a discussion like having someone take your comments out of context, assume facts not in evidence, and attack.

"L0nD0t.$t0we11" wrote in news:EBDKb.75063$I07.370485@attbi_s53:

The interstates will be full of drivers driving that same speed without benefit of 4xd, front wd, snow tires, or experience. I'd think you'd welcome the occasional driver who wants a little extra advantage.

I disagree. Just last month I was traveling on I-78 in New Jersey during the last blizzard we had. I was in 4wd-hi and moving at the speed limit in 3-4" of fresh unplowed snow (the speed limit is 65).

I had no binding of the drivetrain and was in control of the vehicle. There were few other cars on the road and whenever I caught up to one I'd slow down as much as necessary to pass safely.

That was a blast, and I don't consider myself insane. This was no more reckless than traveling 75mph on the same road in "bumper to bumper" traffic during a rainstorm- conditions that happen regularly on that road.

LOL!

Up here in Canada they have a saying: You know you are Canadian when your grandparents drive at 65 mph in a blizzard without blinking.

They aren't kidding either!

I was 'really' pissed and disappointed when my Jeep CJ7 with 31x10.5" mud tires couldn't keep up to the transport trucks in the snow, 4x4 or no 4x4.

Then I got some 'good' sized tires on it for winter driving, 33x9.5's that only have a 7.5" wide footprint and now I can easily keep up at

55-65 mph.

Man I'll tell ya, having a transport truck go blowing past you the same direction in a snowstorm is a trip and 3/4. One I don't enjoy, total whiteout for a minute or more.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Yea! wait until you have to apply the brakes and stop quickly or a heavy gust of wind blows. Your eyes will be really wide open :-)

Driving at high speeds when 4x4 is required is just plain reckless! Asking how fast you can go in 4x4 on snow etc, is a stupid question in my opinion. I'll see you in the ditch :-)

It seems every snowfall there are more SUV's in the ditch than even 2x4 cars etc. I wonder why ? Too cocky maybe

Not knowing how to drive in 4x4 is more likely.

When you hit the brakes in a 2 wheel drive, you only lock up the front tires so you lose steering until you pump the pedal. Jeeps especially have rear anti lock brakes, have since the 70's.

If you are in 4x4 part time and hit the brakes, you lock up all 4 wheels and will slide sideways into the ditch or do 360's faster than you can blink.

People don't know this until it is too late. I even know folks that have done exactly that and still after not known why it happened.

Some folks also don't realize just because you can get going faster easier, you sure can't stop any faster.

If you leave the room to maneuver and know what happens when you hit the brakes, then keeping up with the transport trucks is a good speed to drive in my opinion and around here that is between 55 and 65 mph.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

I've been in LA before when it rained. Those roads turn slicker than ice when rain first hits them. I thought everybody was just being insanely cautious until the first time I drove in those conditions myself.

Over here we get precipitation often enough that no oil or anything else has a chance to build up on the surface to a level like it does out in CA.

Still, if the roads were empty, as they very often are when it snows here, I still think its OK to have a little fun- so long as you are jeopardizing other's lives and property.

Besides, this is a Jeep> Hi Tim,