Preparing for the incline early is important. The keys to successful uphill driving are gears, traction and momentum. If you drive an automatic truck, you don’t have to worry so much about the gears although, if possible, you may choose to change down earlier to keep the revs in the optimal torque band to avoid losing speed early in the incline.
It is wise to disable cruise control on steeper hills so that you have control over the speed without the truck desperately gunning for an unattainable speed.
If you are on a main road or motorway, you don’t have to worry about traction, simply use the appropriate gears. If your lorry won’t be able to maintain its speed, ensure you’re in the left lane on a multi-lane carriageway so that other road users can overtake you.
On long hills, don’t over-rev the engine or you risk overheating it. Let the torque pull you up the hill.
As the gradient levels out, reduce your accelerator input as required, especially if it’s about to turn into a downhill slope. You need to be thinking about your speed downhill.
Slippery surfaces uphill
Maintaining momentum, however slow, is the single most important driving task on slippery uphill surfaces. If you stop, you might not be able to get moving again, and if you wheelspin, you might lose all your momentum.
Use all the available drive wheels; this might mean you need to engage axle interlocks
Don’t tailgate otherwise you might find yourself braking too much and slowing yourself down. If you leave a good 6-10 seconds between you and the vehicle in front, you can smooth out any speed irregularities so that you maintain your speed.
In snowy weather, where it’s not very cold and the rutted snow is thawing slightly, follow the tyre tracks of other vehicles rather than trying to create your own path. However, in very cold temperatures, compacted snow is more slippery than fresh snow, so you may find more traction forging your own path slightly to the left or right of existing tyre tracks.
At some point, you may need snow chains, or to wait for a snow plough. When driving in snowy weather, you should be prepared to have to wait.
Using a Roadranger on a steep uphill
You’ll get to know the characteristics of your engine, and it will depend on the torque and horsepower, so these are rough guidelines that may or may not work for your specific vehicle.
If you’re starting on the hill, you should ideally be in a gear where you simply need to bring up the clutch slowly with no accelerator.
When changing gears you’ll need extra momentum so that you don’t lose all the speed when you dip the clutch. Add around 200-300rpm to your normal downshift. If you usually downshift at 1000rpm, then you’ll downshift at 1200-1300rpm instead because you’ll lose momentum quickly.
You might find that you start to lose speed at 1500rpm, in which case, changing down above there is best. Some trucks have their best performance between 1600-1900.
You might not need to double clutch when going uphill because the revs drop fairly quickly, but you do need to practice the timing. It’s always better on the gearbox to double clutch rather than single clutch or ‘floating’ the gears (no clutch).
If you need more help with a Roadranger, this Roadranger course will help.
The keys to successful downhill driving in an HGV are low speed, correct gear and engaging engine brakes. You should hardly be using your service brakes. The engine brakes and gear selection are the best options to reign in all that kinetic energy. Don’t use cruise control.
As you approach the downhill section, you should be reducing your speed to the speed you want to go downhill. Braking on a downhill slope is much more difficult; braking hard on a downhill slope can easily result in a jackknife situation. It’s best to already be in the correct gear at the start of the slope and maintain a consistent speed all the way down.
On long downhill stretches, stopping in a rest area halfway down is a good way to let your brakes cool off.
Slippery surfaces downhill
10 seconds is a good-sized buffer to the vehicle in front. Keep your speed down. If you lose control it will be extremely difficult to regain control. Using the engine brakes reduces the risk of locking up the wheels.
Some roads have runoff areas to arrest the speed of runaway trucks. Look out for signage for these; hopefully you’ll never need to use one!