TYRES 101

4×4 OFF-ROAD DRIVING TIPS

Following this advice will enable you to get the best out of your 4×4 safely… and have fun!

Before starting out

Before setting out for a trip which may include some off-roading or green-laning, there are some important things to consider to ensure you trip goes smoothly and safely.

Check to see that you are permitted to use the land, and that any local regulations are observed. Be careful not to harm the environment or to endanger or annoy any walkers or cyclists. Take extra care near horses who of course have right of way and could be easily frightened by loud or revving engines – nobody wants a horse injured or to have a hoof print in a door panel!

  • Fill up with fuel and check all fluids levels
  • Study your route well (legislation, rights of way, national parks etc.)
  • Protect vulnerable mechanical parts
  • Take the right kit with you
  • Fording a river
  • Crossing muddy ground
  • Negotiating a step
  • Traversing a slope
  • Cross axle situations
  • Crossing a ditch
  • Descending
  • Ascending

 

Take the right kit with you

You may find that the following equipment will help you:

  • Mobile phone
  • First aid kit
  • Maps, guides and atlases.
  • Satellite navigation system. (There’s no excuse to get lost now!)
  • A complete tool box appropriate to your vehicle.
  • Tow rope or cable: This is essential. It should be capable of pulling several tonnes. Check after each use for damage and replace if necessary.
  • Spade: A spade however will allow you to dig yourself out of trouble in sand, mud or snow. You can find folding spades which weigh very little and take up little space in army surplus stores or on online auction sites.
  • Torch: You can almost guarantee that if there’s going to be a problem, it will be at night! A light weight torch will take up very little space in your glove box. If you use rechargeable batteries it will save on cost too!.
  • Spare wheel/tyre and changing equipment: The strength and durability of BFGoodrich 4×4 tyres has been proven. However, it always pays to be prepared for any tyre related problems. Make sure you have a spare tyre (in good condition and correctly inflated!). If you are unlucky enough to have multiple punctures, an emergency tyre inflation canister may be useful. Take a jack suitable for lifting a 4×4 and a stout board to stop it sinking into soft ground. A bin bag is useful to put a punctured muddy tyre in – if you store it inside the vehicle. Take a pair of stout gloves to handle the tyre – it may have picked up sharp thorns – and a high-visibility vest in case you have to change a wheel in a hazardous location.
  • Suitable clothing: We’re not talking high fashion here, more comfort, practicality and appropriateness for the journey and conditions you expect -or- could encounter. Whether it’s bitter cold or great heat, it’s is better to take a set of spare clothing and not use it, than to need it and not have it!

Fording a river

  • Check out your path in a number of places to avoid surprises (holes, large stones, submerged tree trunks etc) and decide on a line to take and a place to emerge.
  • Check the vehicle’s watertightness.
  • If using All-Terrain or Mud-Terrain tyres, these may be deflated to about 22 psi (1.5 Bar) for certain conditions of load at up to 12mph – contact BFGoodrich tyres for advice.
  • Go gently into the water to avoid thermal shocks and damaging the radiator.
  • Drive at a constant speed (maximum 12mph @ 22psi), pushing through the wave that will form in front of the vehicle.
  • Once the ford has been crossed, look under the vehicle and remove any plants or branches that might be caught.
  • Re-inflate your tyres to the correct pressure for the terrain.

Crossing muddy ground

  • Stop before you get to the mud and study the terrain.
  • Attach emergency straps at the front and rear to avoid having to do it when you are stuck in the mud.
  • If using All-Terrain or Mud-Terrain tyres the tyre pressures may be decreased to improve traction – contact BFGoodrich tyres for advice.
  • Move forward in low ratio, 2nd or 3rd gear.
  • If there are deep ruts, approach them at an angle so that the wheels straddle them and do not go into the ruts. If unavoidable, put the minimum number of wheels into the ruts.
  • Use central and rear wheel differential locking (if the vehicle has it).
  • Keep the wheels straight.
  • Maintain constant acceleration.
  • Try not to stop, but if you become stuck, change immediately into reverse gear and go back.

Negotiating a step

  • Small steps (25cm/10″) are best taken head on.
  • High steps (>25cm/>10″) are best taken at an angle of 45°.
  • In all cases the steps are climbed in low ratio 1st gear.
  • Bring the front wheels right up against the step and apply power.
  • Once the front wheels are over the step, lift off the accelerator to bring the rear wheels against the step.
  • Apply sufficient power to bring the rear wheels over the step.
  • To go down, all steps are taken head on.
  • Control the descent inch by inch, using the brake.

Traversing a slope

  • Survey the slope area on foot, especially the area where you intend exiting the slope.
  • Don’t deflate the tyres too far, to avoid the risk of unseating them.
  • Never trust an inclinometer.
  • Never use differential locking.
  • Tackle the slope in low ratio 1st gear.
  • Turn the front wheels slightly into the slope, so as to progress crabwise.
  • If you start to slide backwards, immediately turn the front wheels towards the base of the slope.

Cross axle situations

  • This is when there is considerable articulation between axles.
  • Study the terrain so that you know the area where the cross axle situation will occur.
  • Lock the central differential and rear axle differential where possible.
  • On the flat or up a hill, change into low ratio 2nd or 3rd gear, and into low ratio 1st when going downhill.
  • On the flat or up a hill, accelerate lightly just before the cross axle point.
  • When going downhill, brake lightly if necessary but never lock the wheels.
  • Should the vehicle’s progress halt, change into reverse and go back, then choose another line or speed.

Crossing a ditch

  • Set the vehicle up in front of the ditch, angled at approximately 45°. Provide for a sufficiently wide exit zone.
  • Lock the central differential and the rear axle differential where possible.
  • Cross the ditch very slowly in low ratio 1st gear using a very light throttle.
  • If the vehicle is stopped by excess articulation between axles, reverse.
  • Start again, taking a different line.
  • Accelerate hard to give you momentum to cross the ditch.
  • Ease off on the accelerator and let the rear wheels cross.

Descending

  • It is essential to change into low ratio 1st gear, before tackling a descent.
  • Lock the central differential and the rear differential if the vehicle has one.
  • Go down slowly using engine braking, without touching the pedals.
  • NEVER USE THE CLUTCH.
  • If the vehicle starts sliding, accelerate carefully to regain traction.
  • On very steep hills, brake lightly as well as using engine braking, and progress inch by inch.

Ascending

  • Lock the differentials.
  • Approach the climb in low ratio 1st or 2nd gear.
  • Accelerate steadily and stay in the ratio you selected initially.
  • Don’t accelerate too hard, or the wheels will spin.

If the vehicle fails to climb the slope or the engine is struggling, you will need to:

  • Secure the vehicle by pushing firmly on the brakes, without touching the accelerator or the clutch, until the engine stalls.
  • While pushing on the brakes, use the clutch pedal to aid selection of reverse gear and gently release all pedals.
  • Turn over the starter motor and let the vehicle descend on engine braking.