Then I’d like, apart from applauding the very neat posts from Lucy, to comment some parts of those posts:
Lucy:
A few more from experience:
- Virgin snow on outside lanes will often give you better traction than compacted snow or slush that has frozen overnight on inside lanes. Don’t be afraid to use it.
- If you get stuck, the following tricks should be tried before concluding that you need help…1. Select a higher starting gear than normal and pull away with as little throttle as you can. If your wagon has idle-away then don’t touch the throttle at all. Otherwise just use a tiny amount. DON’T slip the clutch…2. Make sure your lift axle is raised, if you have one…3. Raise the air suspension on the tractor unit as high as it will go, and dump the air out of the trailer axles. This puts maximum weight on your fifth wheel and hence drive axle. If that has no effect or makes matters worse due to the angle you are on, dump from the unit and raise the trailer. 99.9% of the time this will give you traction to get out of trouble, even on sheet ice… 4. Engage diff locks, if fitted. This should be a last resort, however, as you will lose accurate steering control atthe same time…
Virgin snow gets also my vote, or actually to almost anything else than frozen tyre tracks. Just steering out off the tyre tracks usually gives you much better traction (tyre tracks are often ice and even slush next to it has superior traction). One should also note that this usually applies everywhere. It doesn’t matter if one is steering out off the tyre tracks in a case of hard braking or driving quite near the ditch when turning or taking a ramp off the motorway (most people tend to drive “inside part” of a ramp leaving virgin snow on the “outside part”). Steering off from the dark tyre tracks generally increases traction and can mean the difference between staying on the road or loosing control.
About the getting stuck part, I’d raise the lift axle up as the first thing (and wait until it’s risen) as it gives a very drastic traction increase. Trying to raise the axle up is often advisable even when axle doesn’t raise as in that case many makes alter the suspension air pressure so that more weight is transferred to the drive axle. One can also do this before getting stuck, like when approaching traffic lights on an incline.
Then I’d like to disagree about the diff lock being the last resort. If you wait until you have had wheel spin before applying the diff lock you might be stuck in a situation from which you might very well been able to drive away just by applying diff lock before your first take-off attempt. Also, diff lock doesn’t have to be kept engaged for a long time. Often it’s enough to use it just to get barely moving and disengage it after that.
As this is newbie forum: diff lock can be disengaged while moving; switch off the diff lock from dashboard and ease a bit from a throttle after that to release differential momentarily. This allows diff lock to release itself. After that you can drive just like normally. If diff lock didn’t release itself, don’t worry too much. It’ll release itself soon and steering little bit often helps in releasing it. If ground is slippery you can do some pretty sharp turns without damaging differential so don’t be too afraid about that.
Then my twopence about what to try when stuck before calling for a help. Raise all the axles you can (also from the trailer). After that, actions depend quite much about the situation. For example, on an incline, when pulling away from a bay or when you’re stuck in a flat, ice covered yard I’d engage diff lock. If you can’t get moving with that, next thing to try would be trying to “bounce” lorry out of the hole it’s stuck. This “bouncing” works so that you pull forward as as long as possible. This might not be much, only few centimetres. Immediately when forward motion stops, press the clutch. Don’t let wheels to spin in that kind of situation for long (i.e. when stationary) as that’s very good way to dig yourself even more stuck. After forward motion stop, lorry starts moving backwards by itself. Let it go so for a tiny amount more than the amount you could pull forward (if it doesn’t go by itself, reverse). After that stop and pull forward. Repeat this back and forth action until you’re free or until you can’t get any motion any more (there probably is better English word than “bouncing” for this action). If you have difficulties understanding my meaning think about a ball standing in a shallow hole and how the ball acts when you move it back and forth and how it eventually jumps out of this hole which prevents the movement.
If this fails, then next thing I’d do is to find something to put under the drive axle. It can be almost anything: grit, small rocks, branches, broken roller cages, chains, etc. Often it is surprisingly little extra traction that is needed to get lorry moving.
That high gear trick is also quite handy sometimes, and depending from the gearbox you can do some very nice tricks. For example in 12 gear manual Volvo gearbox, when taking off empty or light, you can let clutch bite a bit at 7th gear and change to 3rd gear in a fraction of seconds.
Just to mention, next quote and reply to it are a bit off-topic so don’t read if my post is too long 
Lucy:
A Jacobs Brake (“jake brake”) is a particularly powerful kind of retarder … in this country should NOT be used in snow and ice, or even on greasy wet roads. …
It’s standard advice in North America, and much advocated by British drivers who have moved over there, that jakes should be used instead of service brakes in winter conditions. If you look around the main forums, there are many debates on the subject, the most interesting being the most recent where even the Scandinavian contributors disagree with this method.
From what I can gather, the reason the advice differs is largely down to 3 things:
- Once ice reaches a VERY low temperature, it starts to become more solid again, and traction improves. We never see temperatures that low in this country, but over there -15 is not by any means unusual, and the normal arguements for use of retarders etc. come back into play.
[/quote]
On this traction behaviour you are very much spot on. When driving on ice or snow covered road on temperatures like -15 C or -25 C you can drive pretty much like at summer, traction often is that god. A rough rule of thumb could be that anything below -10C offers a good traction and another rule of thumb is that most slippery conditions exist around +2 C…-2 C. Regrettably for you, most of the winter driving in UK happens near 0 C, I think.
My experience wont allow me to talk about artics, but with loaded 6x2 rigid/w&d you generally can use exhaust brake on any conditions and retarder/jake brake/VEB/etc. on most conditions even on winter. It’s just this around 0 C area and some snow-on-ice-conditions on which proper care is required with retarders. Some of this also applies to exhaust brake, but to a lesser degree. When empty (i.e. lift axle is up) I’d be much more careful with exhaust brake and retarder as in that case you don’t have the extra sideways traction given by lift axle tyres protecting you from “jack knife” -effect when you lock drive axle up. I’d think this same effect protects artics from jack knife when you’re loaded (i.e. lift axle is down), but it’s just a thought.
