Interesting Stuff Snow!
This article is a brief and basic guide to driving in Snow and Ice conditions and we do recommend if possible that you take a course on Snow/Winter Driving with a suitably qualified 4wd Professional.
Before you undertake ANY Off-Road situations, to make the most of your 4×4, you need to be fully conversant with understanding how the vehicle systems work so you to know how to benefit the most from them. The various traction control systems available on most modern vehicles can assist you however, you still need to understand how they work, how they can help just in case they fail, which they sometimes do. Check out the earlier articles on the Training area of the website about Hi/Low Range ABS/TC/CDL/HDC systems. It is also important to read the Hazard Awareness information. Do that now before you continue to read the rest of this article.
Whenever you are likely to be driving in adverse conditions you need to plan and prepare for it. Pack some extra warm clothing, basic energy food, water, a torch and a first aid kit; these should be the minimum requirements. The following items should also be considered:
Example recovery kit
This basic Snow Driving guide is based around the modern 4wd vehicles, which are likely to be either Permanent 4wd or Part Time 4wd. There are of course a number of common SUV’s about these days, which only have 2wd so owners of those vehicles need to be aware of the needs for driving in adverse conditions for their particular model.
Some SUV’s with 4wd capability are basically 2wd vehicles that have a viscous coupling or other device that activates the transmission as the terrain/situation/traction requirements demand and engages the other axle/wheels to commit to 4wd. Many of these vehicles do not have a Low Transfer Box range of reduction gears.
As mentioned earlier, familiarize yourself so that you fully understand the vehicle’s 4wd system and various controls systems. If you can find a suitable snow covered area such as an empty car park, you can try out the vehicle systems and responses to speed, braking, traction, skids and recovery etc. Do it safely without using chains (to avoid surface damage). Make sure there are no vehicles or pedestrians anywhere near and drive with responsibility, not idiotically.
Off-road winter gathering - practicing techniques in a group
To ensure you pull away smoothly in snow, make sure you have the 4wd fully engaged and if in deep snow perhaps engage the Centre Diff-Lock (CDL) and if the situation dictates, engage Low Range. Some will just try and get away and let the Traction Control (TC) do the work but remember, for TC to work you first have to lose traction to regain it which means you will have incurred wheel-spin. If a wheel spins, you are already making hard work of it. If you have CDL then best to use it should you wish as this reduces the need for the TC to work so hard. You can then disengage it if required but at least by then you are off and away. Always disengage CDL if the Terrain is a hard surface (Tarmac etc.) to avoid transmission wind up of the gears.
Once you have finished this article, go back to our previous article on ABS/TC/CDL and HDC as this will give you a fuller understanding of the systems we are discussing here.
We mentioned earlier, it is best to start off in snow in a High Gear, you would certainly do this in your average 2wd standard car and of course you can use High Range in a 4wd however, usually, if you have Low Range, you are better setting off in the higher gears of that as this provides the more controllable engine torque and traction. You can then change into High Range on the move within the designated speed limitations for the system.
Now you’re on the move and making progress on your chosen off-road track it’s time to keep an eye on the terrain ahead of you. Not just over the end of the Hood/Bonnet/Bull Bar but fifty to sixty metres in front.
Snow can hide a multitude of obstacles especially if there has been any of the stuff drifting in the wind. Fallen tree branches, tree roots, rocks and especially ruts. In the edges of ruts may well be slippery but deeper down they will be as hard as concrete. Any puddles will have frozen and as you drive through, sections of broken ice two, three inches thick or more can suddenly tilt up and get trapped up into the engine bay damaging fans, radiators. Make sure you drive at a gentle pace although you will need to use momentum as and when necessary. This is why you are looking well ahead to plan your route.
It is NOT a good idea to go “off piste” in snow, stick to established tracks and perhaps it’s a good idea to stay in the ruts if they are not too deep as this will stop you sliding off into the side ditches and run offs. Now you are moving in the snow conditions, similar driving to that explained in the earlier article on Mud and Ruts, Ascents, Descents etc. apply, so, it is good to refresh your memory by re-reading those sections also.
As all the various training articles co-relate and link together you will find the various driving control techniques are very similar regardless of the terrain and conditions. Surprisingly, despite the two extremes, some “Sand Driving” techniques apply when driving in Snow conditions. Experience and Knowledge allows you to utilise them as you progress. Re-reading the information of both On and Off-Road Rollovers will lead to some of the answers and slide recovery techniques that arise regarding sliding on snow and ice. Usually, they are speed related such as Over or Under-Steer, Hill Ascents or Descents and also traversing. As well as speed, weight transfer applies. See, it’s all coming together.
As many accidents occur as a result of Ice and Black Ice than happen just as a result of the snow itself. You can see the Snow – Ice however, is something else and often invisible.
Often on tarmac/black top roads, rain or earlier snow, which has melted, can freeze afterwards, normally during the early hours. If there is more snow overnight and the area happens to be shaded from the sun during the following morning you may find yourself driving on what you think is virgin snow and not realise that below that is sheet ice. Without snow chains this can lead to exciting times usually resulting in a slide off on some corner or for those with an “enthusiastic” right foot, the application on too much power can induce a slide that contra steering may not correct before you leave the track or roadway. Be aware of shaded areas and drive accordingly.
Safe travels on your winter excursions
Relying solely on your vehicle’s traction aids may not offer you the security you were expecting in such conditions. Traction control is an asset but when you’re two tons of pride and joy is sliding sideways it usually doesn’t help. Without using chains, there are times when it may be of benefit to reduce tyre pressures to increase the tyre “footprint” (think snow shoes) assuming you have a means to re-inflate. Be aware of possible sidewall damage and make sure your re-inflate for normal road use.
If you do purchase chains, ensure that they are suitable for your particular vehicle also make sure that you undertake instruction from your supplier on how to fit them. Make sure you practise this before the snows arrive, as then is not the time to start to learn. Incorrect or rushed fitment can lead to damage to the tyres and surrounding under vehicle components such as brake lines. With some vehicles, it may not be possible to fit chains to the front wheels due to the type of suspension as they may catch on these due to insufficient clearances. The same applies should you have fitted larger size tyres to standard without the necessary suspension upgrade to match.
The recommendations are always to fit chains to all 4 wheels however. If only 2 chains are available, fit these to the rear wheels while ascending (but be aware of the steering limitations on ascents as the front wheels will become lighter as the weight transfers to the rear).
Fit chains to the front wheels while descending but remember the rear will become lighter.
When driving on more normal terrain fit the chains to the front wheels front as this assists directional control. Be aware that although you have front directional control, the rear may slide if you drive aggressively
Earlier I mentioned staying in the ruts when driving regular tracks, as this should keep you from sliding off into ditches and gullies. Of course, you need to drive with awareness if the ruts have not been previously driven that day as they are likely to be snow filled and you will have no perception of their depth so you could easily finish up caught up by your differentials on the centre ground.
If driving in open ground where your colleague’s vehicles may have driven already, it is usually better for you to drive outside their wheel traces as you will gain more traction on the virgin snow.
Remember, if the snow depth is deeper than your front bumper bar then it is likely that you may not progress very far. Avoid the temptation to charge drifts to push your way through as often you will finish up sat on top of the snow that builds up below the vehicle with all four of your wheels off the ground. This particularly applies if you have bash plates under the vehicle as you just sledge up onto the snow and compact it.
Now is the time to mention “Mechanical Sympathy,” especially for the steering box, steering hydraulics and brake hoses. Deep snow builds up under the front wings and gets trapped and compacts between those and the chassis rails. The more you try and turn the steering, the more pressure you put on the steering hydraulics and this will lead to the various steering box seals leaking, the steering pump screaming its head off and possible distribution belt damage. If you hear the pump screaming it’s an indication of compacted snow so STOP and clear it away.
In amongst the compacted snow trapped under the vehicle there may well be small twigs and branches that have been broken off nearby trees and balled up in the snow. If these have any strength or length and wrap around a brake hose and then become caught under a wheel, the force and strain can rip a brake hose. When you do clear under the wing and chassis area make sure you do it gently and not with a sharp spade or similar as again you could cause damage to any pipework. At all times, avoid excessive acceleration and braking, drive smoothly and make sure that you keep a good distance between any accompanying vehicles. If you have climbs or descents, do a ground recce first to check the terrain and snow depth as well as the usual hazard and run out area checks just in case things go wrong. In snow conditions, they DO. Make sure other vehicles are well clear before you attempt these obstacles and that you are clear before they attempt them. Often it is better to “Marshall” and guide each other through difficult areas.
Taking turns to get up the slope
Well, we have covered the basics, which will hopefully benefit you when faced with Snow and Ice conditions, but I have left a few points to the end so they are up front in your memory banks.
IMPORTANT: No Summary for the SNOW article – JUST RE-READ IT – TWICE!
Enjoy your winter and stay safe
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This content was prepared for the Off-Road Discovery Website by Xplorability 4wd Training
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