Opinions on running 4X4H at 70-80mph?

On the hwy it shouldn't hurt the mechanics of the 4wd. If your around town turning and binding the system up thats another story if you're wrong about ice everywhere

 

Same around here. Except going through the mountain passes on I84. Sweetzer and rattlesnake pass kills several people every year going too fast for conditions.

 

TW welcomes you.

y'know, black ice is the wild card that keeps me up at night when I'm doing this kind of driving. seems the only way to actually prepare for it is total overkill, but the smaller things may help. i use 4x in this situation as much as i can for that reason, but that can be tough on mountain roads so not a consistently usable solution.

 

^^^

 

My bad.. didn't notice you was new or Id have welcomed you as well... ill do better.

 

I wouldn’t recommend driving in snow that fast. As far as 4wd goes. I would do boosted 4wd launches with every diesel I ever owned. There are guys building 4wd drag trucks that go close to 200mph in 4wd. No such thing as a limit to speed for 4wd. Where people come up with this shit is beyond me...

 

Like others have said. 4wd does nothing for you once you break traction on ice, your ass is going in the ditch or into another vehicle. How fast your your going when you do break traction determines how hard you crash.

Its not rocket science.

 

Could you, yep. Should you, probably not.


Every tw motorcycle rider is reciting their favorite saying right now .

"Not a matter of if, just a matter of when...."

 

Coming back through Wolf Creek pass in the thanksgiving snow storm was fun. The speed limit is like 45 through there but people were hauling ass past at 60 with snow and ice on the ground. Did see a few of them in the ditch and one who got pulled over.

I never even put the truck in 4wd

 

I drive through this area multiple times a year and every winter I see large 4x4 trucks slid off all over the place. It is usually some truck that passed me a few miles back thinking they can still go 80 mph. I drive my little front wheel drive jetta and typically have no issues as long as my speed is based on the conditions. There was one year where the snow was so deep on the road that I had to pull over and wait for the plows.

 

Christmas eve of 2016 I was driving back home from utah and it was snowing like a mofo. And coming down the westbound side of rattlesnake I slid alllll the way down it... luckily I know not to pin the brakes and was able to keep it on the road...

 

That might have been the year I had trouble making it up Rattlesnake in the Jetta, obviously coming from the other direction.

 

I think your confused about hubs and transfercase’s, a 4WD Tacoma’s hubs will all spin at different speeds also, unless one axle is locked.

 

The only limitation is the speed of engaging 4WD, which is an engineering consideration for Toyota. They have to consider that you might attempt to engage 4hi in the midst of a slight turn, which will put forces onto the front axle disconnect and transfer case. 50Mph is the maximum speed where those forces can be managed without damage.

Once you have 4hi engaged go as fast as you want.


I find when accelerating on icy roads from 70MPH to 140MPH, the 4WD really helps keep the nose down.

 

The maximum speed limit for the truck is the same in 2WD and 4WD. The owner's manual makes reference to the speed limit (62 mph, 100 km/h) that you need to be below to shift from 2WD into 4WD, however there is no speed limit to shift back from 4WD to 2WD. That can be done at speeds higher than 100 km/h.

As far as types of AWD/4WD, there are really only two types, part time or full time (aka AWD).

Part time 4WD is functionally equivalent to a locked center differential. The same amount of torque is delivered to the front and rear wheels and there is no ability to have a speed differential between them.
Full time 4WD and AWD are interchangeable terms for drive systems that have a centre differential (usually a limited slip of some variety - viscous coupling or helical gear like a Torsen).

There are different ways of orienting the components or controlling the amount of torque transferred, but it basically boils down to one of the following: FWD, RWD, Part Time 4WD, or Full Time 4WD. Usually if someone just says "4WD" or "4x4" they mean part time 4WD, usually if someone says "AWD" they mean full time 4WD.

Jeff

 

Amen!

I was in 4WD going up an icy road in the Smoky Mountains many years ago, somewhere near Maggie Valley if memory serves. I was last in line of four vehicles. The guy up front decided he was about to miss his turn and hit the brakes while trying to turn across the lanes to go left. He went left, alright, but completely out of control and not in the direction he intended. He hit the ditch.

The guy behind him saw it happen and hit his brakes, probably out of reflex. He also went skidding off to the left. Guy in front of me also hit his brakes and went off the road to the right.

I touched my brakes and felt the back end try to catch up with the front end as the tires lost traction. Took my foot off the brakes and managed to get straightened up enough to thread the needle. 4WD helped me get through there but there was a hair's breadth of difference between making it and not. A nanosecond longer on the brakes and I'd also have been in the ditch.

 

Well said

 

4WD doesn’t do jack on ice.

When driving on ice you need weight in the bed.

Also how do you know the others around you had 4WD engaged?

 

He said front wheel drive cars didn't spin.