My commute is 25 miles on interstate and highway. Tonight we had 1/2 inch of snow and it made the interstate slick but not snow packed. My question is can I drive in 4hi at speeds of 35-50 miles per hour? I tried 2wd but I was fish tailing. Other cars were going 60-70.
If the road is slick, you can drive in 4WD.
You can, but better tires and some weight in the back will help. Get one of those heavy plastic lids and put some garage stuff back there in the Winter. You will see a difference. A pickup should have weight in the back. It wasn’t really designed to run empty.
If the roads are bad enough, and even with 4HI, I’m only going to go as fast as I feel safe doing so even if that means 20 MPH or less. To heck with everybody else.
A few years back I spent almost 3 hours driving 50 miles home one night during an ice storm (including 10 minutes getting out of the ditch once) in my 4WD Subaru. 4WD, 1st gear, and creeping and sliding the entire way. Aggravating yes, but I also got home alive.
A number of those fools going around you at 60-70 will be in that percentage mentioned later on the local news; either as a fatality, injured, or just plain lucky at that point in time. The next time may mean they don’t fit into the last category.
If you and other drivers are going 60-70 mph 4WD is not going to help you and could make matter worse. 4WD Does NOT help keep you from loosing control. 4WD does not help keep you on the road 4WD can help you get back on the road if you slide into a ditch or get you through very deep snow (? inch is not deep).
If you want to be safer on the highway with snow or ice, get FOUR real winter tyres not all season. ABS can help you keep control when braking.
While your fishtailing was likely due to lack traction on the back wheels (you always use your best tyres on the back of any car) it would have been far less with modern WINTER tyres. These are not the same as the old snow tyres. They are a new technology and work much better.
When it is slick on the interstate I get in the slow lane and go 45 to 50 if traction allows. It amazes me how fast people drive in bad conditions. I go slow enough where in 2wd I am pretty confident in not sliding off the road. We get alot of blowing snow over the roads which cause a light sheen of ice or some snow pack. Also the roads with go from slick to dry in a matter of a few hunderd yards. So my concern is can you switch back and forth between 4wd and 2wd or would I be better off staying in 4wd and going 40 -50 mph if conditions allow? And what mechanical problems could arise by switching back and forth between 4 and 2wd?
The two most important factors are TIRES and WEIGHT balance. I didn’t read if you had a full size truck…if you do, you need LOTS more of weight to balance a front differential and a V8. Otherwise, even in 4wd you’re asking for trouble. As stated. 4 wd can sometimes get you into trouble faster than two wheel drive. I’ve alwasy kept 350+ lbs in the back of a compact truck and drove only as fast as 2 wd would allow with studded tires on all wheels using 4 wd to negotiate hills etc. Otherwise, you’ll be tempted to drive faster than conditions permit.
AWD, which adjust forward/backward bias does much to keep you from fishtailing and under control. Again a trade off if you foolishly use it to outdrive your traction and balance capabilities.
In my opinion, a 4wd truck in slippery ON ROAD weather W/o proper weight and tires, is one of the MOST dangerous vehicle you can drive. I’ve owned every type of drive system in all sorts of weather, and that’s my take.
I have a 2000 tacoma and it is very light and fishtails easily if I am driving too fast. That is why I really try to drive only as fast as 2wd would allow. I am the slow driver that everyone curses at. I have 200lbs in the back but I think I will up that to the 350 range you suggested. My tacoma is perfect for driving in town in bad weather but it is not suited for the interstate where people drive like maniacs.
Do not drive a part time 4 WD at highway speeds!! There is no differential between the front and rear axles, which means that both axles musts rotate at the same speed. The front and rear differentials will allow the right and left wheels to rotate at different speeds, but that will not compensate for the absence of a center diff.
I’m sure your owner’s manual says not to do this. On a dry road the drive train will bind when you round a corner in 4 WD. On a slippery road the drive train won’t bind because the tires will slip. You don’t need the tires slipping on every curve when driving on a slippery road.
Some time ago I heard a caller (to Click and Clack) tell about driving along a slippery road in PT 4WD when the truck simply rotated and spun into a ditch. He was traveling along a straight section road at the time.
1/2 of snow should NOT cause to you to fish tail…unless it was very cold and basically turned everything to ice.
You should not have a problem driving in 4wd…but if the roads are that slick I sure wouldn’t be driving at 60-70. You sure would be able to stop quickly if the roads are that slick.
When ever I’m in 4wd in the interste it’s because the roads are very bad and I’m usually doing no more then 45. Many times around 30.
With the mention of part time i am assuming you are driving any 85-95 subaru gl or loyale. otherwise a brat, hatchback , or 80-84 wagon
Yes, you can drive in part time 4wd at highway speeds with the right conditions permitting, and as fast as you are confident to drive.
Although the front and rear differentials are open, the rear drive is enabled from a PTO shaft on the transmission, and is not a differential. Because of this you only want to engage or disengage the 4wd from 2wd when the sttering is straight and preferably when the car is moving. You can drive the car on snow or ice, gravel roads, sand, mud and heavy rain at moderate speeds. you should not use 4wd on dry pavement, ir in the rain with slow speed in-town type traffic.
You can switch in and out of 4wd at any speed. Athough when selecting lo range you will need to clutch and match a gear accordingly. 5th gear low is close to 3rd gear hi.
you will feel the steering is tighter when in 4wd, amnd will spread braking forces equally across the font to rear axles
Sure you can drive in 4HI at 35 to 50. That’s exactly what it’s there for. THe question is, should you be driving that fast in any gear when it’s slick? 4WD will give you more stability in almost all conditions. Yes, that’s not what Joseph said, but in my wife’s Jeep it is definitely the way it is.
I’m curious what make and model of vehicle you are driving. Some Jeep 4WD vehicles have a selector that shows 2WD, full time 4WD HIGH, part time 4WD HIGH, and 4WD LOW (which is also a part time setting). I am most familar with Jeeps. The PART TIME settings are to be used exactly as they say, PART TIME. It is for getting you out of the ditch after you spin out, which you will if you drive too fast. On a Jeep, I would suggest using FULL ITME 4WD for alomst all adverse driving conditions. It’s even better on our local gravel roads.
I’d like the OP to state exactly what type of vehicle he’s asking about, and also to tell us what the owner’s manual says. Several responders have made statements about Subarus, which I believe do not have part time 4WD. Others have discussed the alternative 4WD, AWD, hi, low, settings that are available in certain Jeeps. It seems many responders don’t know the difference between part time 4WD and AWD, et al.
So my concern is can you switch back and forth between 4wd and 2wd or would I be better off staying in 4wd and going 40 -50 mph if conditions allow?
I wouldn’t switch back and forth at those speeds. It’s perfectly fine to drive in 4hi on the expressway. The key is to make sure that most of the time, one wheel on each axle can slip to account for the differences in rotational speed. I often drive with one side on dry pavement and the other on snow and the system is perfectly happy to do that. When you switch the transfer case with automatic hubs, you’ll be introducing a change in axle speed and traction that could easily start you into a spin. On snow and ice, steady speed and no abrupt changes are best. If you get to dry pavement and it appears like it will stay that way for a long time, then switch out.
And what mechanical problems could arise by switching back and forth between 4 and 2wd?
My vehicle does not have any warnings against switch in/out of 4hi at any speed. I tend to favor doing it at speeds below 40mph though since I remember the old school systems that couldn’t tolerate it. Check your owner’s manual to be sure.
My truck also has an automatic 4 wheel drive mode where it will engage 4hi if it detects wheel spin. I find this to be worthwhile at slow speeds but unnerving at highway speeds as there is an abrupt change that occurs during the transition. YMMV.
4wd systems these days are computer controlled. There’s no reason what so ever not to be able to switch from 2wd to 4hi and back at any speed. My 84 S-15 and 90 Pathfinder had a limit of 50mph…My 98 Pathfinder and 05 4runner don’t have this restriction. And when I shift into 4wd…it’ll stay in 2wd until it feels it can safely switch. It might take a second or two.
"4WD will give you more stability in almost all conditions. Yes, that’s not what Joseph said, but in my wife’s Jeep it is definitely the way it is. "
I have not personally tested it, but I have seen reports from test conditions and the end result is you are more likely to maintain control under slippery road conditions with 4WD off. It may well “feel” more secure, but until you have actually tested it on a test track, I will suggest those who have are in a better position to make the determination.
Not all 4wd drive systems are computer controlled, not even today. Most are, but there are still manual systems out there (Jeep Wrangler is an example).
Have you tried referring to your owner’s manual for advice? That’s your best source.
If it’s slippery enough for you to fishtail at 35, it’s slippery enough to use 4WD high range.
And Lars, the Subarus that Miles mentioned did in fact have part-time 4WD.
I have not personally tested it, but I have seen reports from test conditions and the end result is you are more likely to maintain control under slippery road conditions with 4WD off. It may well “feel” more secure, but until you have actually tested it on a test track, I will suggest those who have are in a better position to make the determination.
Well I have tested it MANY times. …And you have a LOT MORE CONTROL under slippery road conditions when 4WD IS ON. What I think many people do is drive their vehicle in 4wd beyond what the vehicle can do thus causing them to have control problems.
Here’s a test for you…Start in Syracuse NY and drive to WaterTown NY on interstate 81 during one of the 1-200 HUNDRED lake effect storms they have each year. IF you even make it to Watertown in RWD I’d be very very surprised. You NEED 4wd just to keep traction…or a good 4wd vehcile with 4 snows…and don’t forget some very good snow driving skills.