4x4 and winter driving - general information
#1
01-03-2015, 06:47 AM
4x4 and winter driving - general information
It's winter and I will share a bit about the experience I made while driving in slippery conditions on snow or such.
I'll split it into the 3 modes available with the Blazer and extend a bit on warnings and technicalities. At the end you will find some links to good sources of information. Always plan with enough time. Get there when you get there but safe.
ABOUT 2HI
--------------------------------------------------------------------------------------
Whenever driving on roads which are only wet or even dry I switch back to 2HI in order not to stress the drivetrain. The blazer has no center differential and tight turns with 4x4 engaged will result in the drivetrain building up tensions because of the different turning radii the front and rear wheels have. (more at the end in TECHNICALITIES).
Make sure you engage the 4x4 before entering snow or slippery surfaces. The 1st gen has front disc brakes and rear drum brakes. In 2HI you drive the rear axle. I live in a condo with a parking garage and it happened to me several times that when exiting from the dry/wet garage into the snow onto the road in 2HI it pushed me out into the street. This is because you apply brakes as you're used to do but the front wheels in the snow lock up below ABS speed and the rear drum brakes are not braking that well. Eventually the engine is still cold and running in high idle which pushes you forward.
The only thing to do is step onto the brakes hard. This will engage the rear brakes and stop the motion.
This is also true for driving in 2HI in snow. As the front brakes do 90% of the job and the rear drum brakes due to the technical limitations they have will engage only later it may happen that the ABS is regulating on the front wheels already at very low brake pressures but the rear axle is not yet braking and the engine pushes you happily along anyway. Again hit the brake hard or engage 4x4 before entering such conditions.
Obviously with only the rear axle driven, traction is not terrible in snow and the tail will skid and try to get ahead of you. (vehicle physics) So you are back to your normal rear axle drive car behavior.
ABOUT 4HI
--------------------------------------------------------------------------------------
The 4x4 does a terrific job in the Blazer to stabilize your drive. Definitively what you want when driving in snow. As the front wheels are driven as well, it eases the way it drives through ruts and the ridges of slush and snow, you may find on highways when changing lanes or entering. It improves steering and acceleration.
Make sure you have good tires apt for snow & mud. All 4x4 is worthless when you have no means to get traction from the wheels onto the ground. On snow and slippery surfaces you may want to start with 4HI. Unless you drive up steep hills or offroad I nearly never used 4LO on the street in snow.
It can become fun when you see others with 2WD cars being stuck in the barest of snow cover and you just pull away from the red light as nothing were. Nevertheless have a close look at the warnings below.
ABOUT 4LO
--------------------------------------------------------------------------------------
The 4LO gives you double the torque at the same rpm and cuts speeds in half at the same rpm. Therefore it reacts more agressive than 4HI. While it may be a good thing when towing a heavy trailer I hardly ever felt the need for it in snow on roads. Offroad is another story. I have been using 4LO in snow over 1 foot deep to see if it improves driving but found it not really necessary. This is a thing of experience.
W A R N I N G S
--------------------------------------------------------------------------------------
The SUV is some 3'500 lbs empty mass. Take this into consideration when driving especially downhill! You cannot cheat the laws of physics especially not Newtons! Just because it is absolutely not the same as driving around in a Chevrolet Caprice, which you will have trouble getting to go at all on snow, does not mean it will stop the same as it accelerates. In corners, the side forces are the same for all cars. So it won't go any faster through the next corner than the 2WD you have eventually driven in snow.
Cornering speeds may even be less than what you could handle with a Toyota Corolla! I found it difficult to get a good set of winter tires and ended up either with Pirelli or with a Finnish brand. Have to look that one up. The trouble with winter tires on the 1st Blazer is not traction but poor cornering forces.
ADVICE
--------------------------------------------------------------------------------------
Go looking for a nice big parking lot where to try the Blazer. Make sure you know where the speed bumps are and where the parking lot limiting bars, edges, and plant areas are. You do not want to slide into these sideways (rollover). Try acceleration and braking to get a feel. Start a 5mph then 10mph and as far as you dare. In snow anything above 30mph is FAST! Then you NEED TO KNOW WHAT YOU ARE DOING!
Try acceleration in (D), (3), (2) or even (1) and hand shift upwards. Try this with 2WD - 4HI - 4LO at low speeds. Try cornering. What happens when you accelerate with the wheels turned.
Braking is the same. Start at low speeds. So you can find out where the cutout speed of your ABS is. How is it braking with ABS. Try that in 2HI and 4HI and get a feel for the difference. Usually in 4x4 it brakes much better because the rear axle is braked through the drivetrain and does no longer push into the locking front wheels.
Keep everything smooth. Smooth on the accelerator and steering. Look ahead and anticipate road conditions and traffic situations. Make your clothing comfortable. Take off what you do not need - even stop after 5 min. of driving when the car has heated up. I see too many IMHO "stupid guys" driving around all clothed up and having the heating turned down so all the windows will get foggy.
IMPORTANT: Get rid of all distractions such as: Smoking (not a joke), this is a major distraction in snow and messes up your windows! No loud music or no car stereo at all. NO PHONE WHATSOEVER - have it in flight-mode when driving. This is rated the strongest distraction just after a crying child. Make children comfortable and explain them that you cannot have your attention distracted by them and will therefore not react to them right away but only after pulling over. This could avoid quite a lot of fender-benders.
GENERAL ADVICE
--------------------------------------------------------------------------------------
Get a feel for winter driving also on the car as a whole. Where do you live? Make sure you pack your car with the necessary equipment for your area. Shovel, snow chains, piece of cardbord or piece of old carpet (to kneel on), towing rope, battery jumper cables, insulation blanket, depending on blizzard hazards - sleeping bag etc. you name it. You may ask your local police what they think is helpful if people had that on board. Check your lights, the quality of the antifreeze in the radiator and make sure the windshield washer fluid tank is always at least half full and has an adequate amount of anti-freeze in it. Have your battery checked - still one of the main problems in winter. Have your cars locks sprayed with a good oil spray and do not spray water into the locks when washing the car.
De-ice equipment is a must in winter. I do start up my car first thing, then put it on defrost and a middle fan speed and full heat. Make sure the car is unlocked and there is no possibility that you can inadvertently lock it with the key inside. (E.g. separate remote control from ignition key). Then start removing the snow from your car. Remove ALL THE SNOW! The guys who think it is cool to drive around with a foot of snow on the roof will have some nasty surprises once the car heats up and it slides down at the slightest of breaking. At least it will make you blind as it piles up on the windshield - if unlucky you crash - it can kill you/others - definitively kills your wipers - your antenna - go figure. Plus in some states you get a ticket for it.
The same goes for the windshield. I have mine always completely de-iced. Else in really cold weather even with the smallest amount of ice the wipers may pass over the remaining ice which will start to lift the wiper and you can watch grow the ice patch again on you. Wait as long as it takes to defrost it completely on the inside.
For the equipment: shovel to get to your car, brush or something to remove snow from the body, some means of scratching ice off windows, gloves against stiff fingers. Proper rope to get others out of the snow - or being pulled back onto the street
Know how to mount your snow chains or other equipment etc. Put your snow chains on once in the garage or in a nice and dry spot (even warm). Then move outside to your driveway, local parking lot, somewhere with a lot of snow and put them on there in the cold, deep snow, cold hands... and have the person driving the car do the same
TECHNICALITIES
--------------------------------------------------------------------------------------
2 HI = Rear wheel drive through 4 speed automatic transmission throught transfer case to rear differential to wheels.
4 HI = Adds front wheels through transfer case which connects short drive shaft to front wheels. (Method of changing, manual/electric is pretty much irrelevant because in either case the internals on the transfer case and front wheel drive are the same.)
NOTE: The S10 features NO differential in the transfer case. This is the cause for the jumping sensation when turning on pavements which have some friction, such as paved or a solid dirt road. It cannot equalize the different speeds between front and rear wheels. Sometimes when accelerating a bit you get a jumping in the car also called "crow hopping" when the wheels start to slip to force an equalization.
4 LO = Adds a reduction in the transfer case which is applied to the drivetrain rear-/forward. This doubles the torque and cuts revolutions to half (approximately). This means you need double the engine rpm to reach the same speed. At the same time the torque is doubled which means that the symptoms such as acceleration or the jumping and rubbing of tires on hard surface is more pronounced as well.
NOTE: This kind of 4x4 is not meant to be used on dry or hard surfaces with good grip and full turns at tight radii. I use my steering wheel on this kind of surface only for 3/4 of a turn of the wheel and eventually back up to get around tight corners in order not to stress the drivetrain. On slippery surfaces it does a hell of a job because you always get torque to front and rear end.
Because of the high rpm in 4LO required to drive the same speeds and a change in behaviour of the automatic transmission when releasing the accelerator pedal you have a strong braking sensation. It should be that way because it is designed to climb and descend steep inclines without the need for braking in off-road driving.
I've been up 25 to 30 degree slopes in nearly idle. I've been up 45 degree (100 %) slopes - scary and down nearly as much without braking. The only pretty useless thing in offroading in the S10 is the ABS.
Hope that helps a bit of understanding to some of the behaviour described in this thread.
LINKS
--------------------------------------------------------------------------------------
https://exchange.aaa.com/safety/driv.../#.XfIpv-hKjD4
Guidance material.
ABOUT ME AND MY DRIVING EXPERIENCE
--------------------------------------------------------------------------------------
I've started driving cars at age 18 many, many, many moons ago - hmmp 30+ to be precise. A year later I had my first motorbike a 125 ccm two stroke street machine. 3 years later my first big bike a Moto Guzzi Le Mans IV 1000 ccm followed by a Ducati 900 SS in 1991. As for cars since age 20 i drove myself around 1'000'000 km's on all kind of vehicles and spent some 500'000 km as co-driver. At age 20 in the Swiss Army Pioneers I became a truck driver driving anything from the ****** Jeep's that we still had in 1987 over 3.5 and 5.0 ton trucks from SAURER model years 1945 until 1952 unsynchronized 4x4 trucks over SAURERS more modern 1960's 2DM the modern SAURER 6DM and 10DM, the Austrian STEYR 6x6 with all sorts of trailers in all conditions including 2 feet of snow at -11 degrees Celsius. I live close to the mountains in Switzerland and eventually we get snow every year at least for a couple of days. This year for 2 weeks in a row we had more or less snow covering nearly all streets. Nice driving in my Saab as my Blazer is at the shop right now.
As a trained off-roader in all vehicles from a Haflinger http://en.wikipedia.org/wiki/Haflinger_(vehicle) to the large trucks Saurer 10DM - Wikipedia, the free encyclopedia I have seen my share of situations and also all kind of bad and weird stuff that can happen. The same goes for snow. I try to always back up my advice with reliable sources such as the links provided for further reading and try not to post nonsense. If someone disagrees and gets me a good reasoning let me know.
And as always I will deny any responsibility for anything. Use good judgement. RTFM. Get yourself informed.
I'll split it into the 3 modes available with the Blazer and extend a bit on warnings and technicalities. At the end you will find some links to good sources of information. Always plan with enough time. Get there when you get there but safe.
ABOUT 2HI
--------------------------------------------------------------------------------------
Whenever driving on roads which are only wet or even dry I switch back to 2HI in order not to stress the drivetrain. The blazer has no center differential and tight turns with 4x4 engaged will result in the drivetrain building up tensions because of the different turning radii the front and rear wheels have. (more at the end in TECHNICALITIES).
Make sure you engage the 4x4 before entering snow or slippery surfaces. The 1st gen has front disc brakes and rear drum brakes. In 2HI you drive the rear axle. I live in a condo with a parking garage and it happened to me several times that when exiting from the dry/wet garage into the snow onto the road in 2HI it pushed me out into the street. This is because you apply brakes as you're used to do but the front wheels in the snow lock up below ABS speed and the rear drum brakes are not braking that well. Eventually the engine is still cold and running in high idle which pushes you forward.
The only thing to do is step onto the brakes hard. This will engage the rear brakes and stop the motion.
This is also true for driving in 2HI in snow. As the front brakes do 90% of the job and the rear drum brakes due to the technical limitations they have will engage only later it may happen that the ABS is regulating on the front wheels already at very low brake pressures but the rear axle is not yet braking and the engine pushes you happily along anyway. Again hit the brake hard or engage 4x4 before entering such conditions.
Obviously with only the rear axle driven, traction is not terrible in snow and the tail will skid and try to get ahead of you. (vehicle physics) So you are back to your normal rear axle drive car behavior.
ABOUT 4HI
--------------------------------------------------------------------------------------
The 4x4 does a terrific job in the Blazer to stabilize your drive. Definitively what you want when driving in snow. As the front wheels are driven as well, it eases the way it drives through ruts and the ridges of slush and snow, you may find on highways when changing lanes or entering. It improves steering and acceleration.
Make sure you have good tires apt for snow & mud. All 4x4 is worthless when you have no means to get traction from the wheels onto the ground. On snow and slippery surfaces you may want to start with 4HI. Unless you drive up steep hills or offroad I nearly never used 4LO on the street in snow.
It can become fun when you see others with 2WD cars being stuck in the barest of snow cover and you just pull away from the red light as nothing were. Nevertheless have a close look at the warnings below.
ABOUT 4LO
--------------------------------------------------------------------------------------
The 4LO gives you double the torque at the same rpm and cuts speeds in half at the same rpm. Therefore it reacts more agressive than 4HI. While it may be a good thing when towing a heavy trailer I hardly ever felt the need for it in snow on roads. Offroad is another story. I have been using 4LO in snow over 1 foot deep to see if it improves driving but found it not really necessary. This is a thing of experience.
W A R N I N G S
--------------------------------------------------------------------------------------
The SUV is some 3'500 lbs empty mass. Take this into consideration when driving especially downhill! You cannot cheat the laws of physics especially not Newtons! Just because it is absolutely not the same as driving around in a Chevrolet Caprice, which you will have trouble getting to go at all on snow, does not mean it will stop the same as it accelerates. In corners, the side forces are the same for all cars. So it won't go any faster through the next corner than the 2WD you have eventually driven in snow.
Cornering speeds may even be less than what you could handle with a Toyota Corolla! I found it difficult to get a good set of winter tires and ended up either with Pirelli or with a Finnish brand. Have to look that one up. The trouble with winter tires on the 1st Blazer is not traction but poor cornering forces.
ADVICE
--------------------------------------------------------------------------------------
Go looking for a nice big parking lot where to try the Blazer. Make sure you know where the speed bumps are and where the parking lot limiting bars, edges, and plant areas are. You do not want to slide into these sideways (rollover). Try acceleration and braking to get a feel. Start a 5mph then 10mph and as far as you dare. In snow anything above 30mph is FAST! Then you NEED TO KNOW WHAT YOU ARE DOING!
Try acceleration in (D), (3), (2) or even (1) and hand shift upwards. Try this with 2WD - 4HI - 4LO at low speeds. Try cornering. What happens when you accelerate with the wheels turned.
Braking is the same. Start at low speeds. So you can find out where the cutout speed of your ABS is. How is it braking with ABS. Try that in 2HI and 4HI and get a feel for the difference. Usually in 4x4 it brakes much better because the rear axle is braked through the drivetrain and does no longer push into the locking front wheels.
Keep everything smooth. Smooth on the accelerator and steering. Look ahead and anticipate road conditions and traffic situations. Make your clothing comfortable. Take off what you do not need - even stop after 5 min. of driving when the car has heated up. I see too many IMHO "stupid guys" driving around all clothed up and having the heating turned down so all the windows will get foggy.
IMPORTANT: Get rid of all distractions such as: Smoking (not a joke), this is a major distraction in snow and messes up your windows! No loud music or no car stereo at all. NO PHONE WHATSOEVER - have it in flight-mode when driving. This is rated the strongest distraction just after a crying child. Make children comfortable and explain them that you cannot have your attention distracted by them and will therefore not react to them right away but only after pulling over. This could avoid quite a lot of fender-benders.
GENERAL ADVICE
--------------------------------------------------------------------------------------
Get a feel for winter driving also on the car as a whole. Where do you live? Make sure you pack your car with the necessary equipment for your area. Shovel, snow chains, piece of cardbord or piece of old carpet (to kneel on), towing rope, battery jumper cables, insulation blanket, depending on blizzard hazards - sleeping bag etc. you name it. You may ask your local police what they think is helpful if people had that on board. Check your lights, the quality of the antifreeze in the radiator and make sure the windshield washer fluid tank is always at least half full and has an adequate amount of anti-freeze in it. Have your battery checked - still one of the main problems in winter. Have your cars locks sprayed with a good oil spray and do not spray water into the locks when washing the car.
De-ice equipment is a must in winter. I do start up my car first thing, then put it on defrost and a middle fan speed and full heat. Make sure the car is unlocked and there is no possibility that you can inadvertently lock it with the key inside. (E.g. separate remote control from ignition key). Then start removing the snow from your car. Remove ALL THE SNOW! The guys who think it is cool to drive around with a foot of snow on the roof will have some nasty surprises once the car heats up and it slides down at the slightest of breaking. At least it will make you blind as it piles up on the windshield - if unlucky you crash - it can kill you/others - definitively kills your wipers - your antenna - go figure. Plus in some states you get a ticket for it.
The same goes for the windshield. I have mine always completely de-iced. Else in really cold weather even with the smallest amount of ice the wipers may pass over the remaining ice which will start to lift the wiper and you can watch grow the ice patch again on you. Wait as long as it takes to defrost it completely on the inside.
For the equipment: shovel to get to your car, brush or something to remove snow from the body, some means of scratching ice off windows, gloves against stiff fingers. Proper rope to get others out of the snow - or being pulled back onto the street
Know how to mount your snow chains or other equipment etc. Put your snow chains on once in the garage or in a nice and dry spot (even warm). Then move outside to your driveway, local parking lot, somewhere with a lot of snow and put them on there in the cold, deep snow, cold hands... and have the person driving the car do the same
TECHNICALITIES
--------------------------------------------------------------------------------------
2 HI = Rear wheel drive through 4 speed automatic transmission throught transfer case to rear differential to wheels.
4 HI = Adds front wheels through transfer case which connects short drive shaft to front wheels. (Method of changing, manual/electric is pretty much irrelevant because in either case the internals on the transfer case and front wheel drive are the same.)
NOTE: The S10 features NO differential in the transfer case. This is the cause for the jumping sensation when turning on pavements which have some friction, such as paved or a solid dirt road. It cannot equalize the different speeds between front and rear wheels. Sometimes when accelerating a bit you get a jumping in the car also called "crow hopping" when the wheels start to slip to force an equalization.
4 LO = Adds a reduction in the transfer case which is applied to the drivetrain rear-/forward. This doubles the torque and cuts revolutions to half (approximately). This means you need double the engine rpm to reach the same speed. At the same time the torque is doubled which means that the symptoms such as acceleration or the jumping and rubbing of tires on hard surface is more pronounced as well.
NOTE: This kind of 4x4 is not meant to be used on dry or hard surfaces with good grip and full turns at tight radii. I use my steering wheel on this kind of surface only for 3/4 of a turn of the wheel and eventually back up to get around tight corners in order not to stress the drivetrain. On slippery surfaces it does a hell of a job because you always get torque to front and rear end.
Because of the high rpm in 4LO required to drive the same speeds and a change in behaviour of the automatic transmission when releasing the accelerator pedal you have a strong braking sensation. It should be that way because it is designed to climb and descend steep inclines without the need for braking in off-road driving.
I've been up 25 to 30 degree slopes in nearly idle. I've been up 45 degree (100 %) slopes - scary and down nearly as much without braking. The only pretty useless thing in offroading in the S10 is the ABS.
Hope that helps a bit of understanding to some of the behaviour described in this thread.
LINKS
--------------------------------------------------------------------------------------
https://exchange.aaa.com/safety/driv.../#.XfIpv-hKjD4
Guidance material.
ABOUT ME AND MY DRIVING EXPERIENCE
--------------------------------------------------------------------------------------
I've started driving cars at age 18 many, many, many moons ago - hmmp 30+ to be precise. A year later I had my first motorbike a 125 ccm two stroke street machine. 3 years later my first big bike a Moto Guzzi Le Mans IV 1000 ccm followed by a Ducati 900 SS in 1991. As for cars since age 20 i drove myself around 1'000'000 km's on all kind of vehicles and spent some 500'000 km as co-driver. At age 20 in the Swiss Army Pioneers I became a truck driver driving anything from the ****** Jeep's that we still had in 1987 over 3.5 and 5.0 ton trucks from SAURER model years 1945 until 1952 unsynchronized 4x4 trucks over SAURERS more modern 1960's 2DM the modern SAURER 6DM and 10DM, the Austrian STEYR 6x6 with all sorts of trailers in all conditions including 2 feet of snow at -11 degrees Celsius. I live close to the mountains in Switzerland and eventually we get snow every year at least for a couple of days. This year for 2 weeks in a row we had more or less snow covering nearly all streets. Nice driving in my Saab as my Blazer is at the shop right now.
As a trained off-roader in all vehicles from a Haflinger http://en.wikipedia.org/wiki/Haflinger_(vehicle) to the large trucks Saurer 10DM - Wikipedia, the free encyclopedia I have seen my share of situations and also all kind of bad and weird stuff that can happen. The same goes for snow. I try to always back up my advice with reliable sources such as the links provided for further reading and try not to post nonsense. If someone disagrees and gets me a good reasoning let me know.
And as always I will deny any responsibility for anything. Use good judgement. RTFM. Get yourself informed.
Last edited by error_401; 12-12-2019 at 05:55 AM. Reason: style, typo and links
#2
12-12-2017, 06:06 PM
Very good information here. I know this thread is a little old but the information isn't. I've got a 94 S10 Blazer that I haven't had a chance to get on the road yet. As I live in the hills of Pennsylvania, this information is very helpful. I've also never owned a Blazer before. Lots of trucks, SUV's, but no Blazer, especially a 1st gen. I should be getting it on the road in the next couple of weeks and I'm sure we'll be talking a lot. I've got a whole boat load of ideas and dreams I want to do so I hope so. This forum has been so useful so far, I've learned so much. I'm actually kind of glad I haven't put it on the road yet as I've learned a few of the "first steps" that I can't say I would've figured out on my own. Again, thanks for the info.
#3
12-12-2017, 09:11 PM
error_401, great info.
I especially appreciate the advice to practice in an abandoned parking lot. I did that when I was learning to drive. It is quite the experience to purposely put a 1971 302 cid powered Ford station-wagon into a skid on a snowy/slippery road. But doing it under controlled conditions is a big help for when it happens unexpectedly.
This came in handy later when in college driving over the Oregon Cascade mountains with my 1971 Dodge Dart with a 318 cid engine. Like the Ford, with so much power with only rear wheel drive, one has to be very mindful of the diminished amount of friction due to the snow. I still have the old packing blanket I use for laying on when I put on my chains. For the Dart, it was the old-style link chains.
Regarding driving in 4Hi on pavement, an image that will never leave me is the sight of a Jeep Cherokee on a long overpass/on-ramp south of Portland Oregon with the front end of the front drive axle on the ground because the front universal joint broke due to the driver having forgotten to take their Jeep out of 4Hi after driving through a section of highway with ice on it.
One final thought, once your tires are no longer rotating with the road or worse sideways to your direction of motion, you are no more than a 2 ton hockey puck and no amount of 4wd will help. This is why you turn your front tires in the direction of motion so as to get them rotating with the road after which you can have a bit more control.
Drive safe out there!
I especially appreciate the advice to practice in an abandoned parking lot. I did that when I was learning to drive. It is quite the experience to purposely put a 1971 302 cid powered Ford station-wagon into a skid on a snowy/slippery road. But doing it under controlled conditions is a big help for when it happens unexpectedly.
This came in handy later when in college driving over the Oregon Cascade mountains with my 1971 Dodge Dart with a 318 cid engine. Like the Ford, with so much power with only rear wheel drive, one has to be very mindful of the diminished amount of friction due to the snow. I still have the old packing blanket I use for laying on when I put on my chains. For the Dart, it was the old-style link chains.
Regarding driving in 4Hi on pavement, an image that will never leave me is the sight of a Jeep Cherokee on a long overpass/on-ramp south of Portland Oregon with the front end of the front drive axle on the ground because the front universal joint broke due to the driver having forgotten to take their Jeep out of 4Hi after driving through a section of highway with ice on it.
One final thought, once your tires are no longer rotating with the road or worse sideways to your direction of motion, you are no more than a 2 ton hockey puck and no amount of 4wd will help. This is why you turn your front tires in the direction of motion so as to get them rotating with the road after which you can have a bit more control.
Drive safe out there!
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