THE NUM­BERS ADD UP

4 x 4 Australia - - Techniques -

LET’S as­sume our loaded 4x4 – in­clud­ing a trailer, long-range tanks and a bike rack on the back for kids – weighs in at ex­actly 6000kg. If you were to push

1. The gear you need to per­form a dou­ble line pull is found in most off-the-shelf re­cov­ery kits. 2. A pul­ley block is one of the most un­der­rated pieces of re­cov­ery equip­ment. The ex­tra pulling force and abil­ity to re-di­rect winch lines can make for im­pres­sive re­cov­ery tech­niques. this on flat, smooth ground, the force re­quired would only be 10 per cent of the to­tal weight (600kg). That 12,000lb winch could drag you and an­other eight 4x4s rea­son­ably eas­ily.

For ev­ery 15 per cent of up­wards slope, you need to add 25 per cent of the to­tal load onto what force is re­quired. So on smooth ground, with a 45-de­gree slope, you’re now re­quir­ing 5100kg of pulling abil­ity, just 300kg shy of the winch’s max­i­mum pulling abil­ity.

Add a busted wheel bear­ing (so you’re drag­ging a dead weight) and you can see an ad­di­tional 75 per cent of the to­tal load bring­ing us up to 9600kg of force re­quired. Mud com­pli­cates things even fur­ther. Fully loaded in chas­sis-deep mud can re­quire a ridicu­lous amount of force (18,600kg, or 41,000lb). That 12,000lb winch isn’t look­ing so strong on its own any­more, is it?

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