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This edition published by 4xoverland in 2014 6 The Kippings, Thurlby, Lincolnshire England PE10 0HY +944 (0) 7946 650541 www.4xoverland.com First published as The Complete Guide To Four-Wheel Drive in 1993 in South Africa by International Motoring Productions. 8th edition, 1st imprint. © Andrew St. Pierre White 2014 All rights reserved. Photographs: © Andrew St. Pierre White, unless otherwise indicated Diagrams: © Andrew St. Pierre White, unless otherwise indicated This book and its contents is copyright under the Berne Convention in terms of the Copyright Act (Act 98 of 1978). No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical including photocopying, recording or by any information storage and retrieval system, without permission in writing from the publisher. THOSE OF US LUCKY ENOUGH TO FIND OURSELVES IN THE EARTH’S SECRET PLACES HAVE OUR DEBTS TO PAY. IF WE ABUSE THE ENVIRONMENT WITH OUR 4X4s, OR TAKE FOR GRANTED OUR RIGHT TO GO THERE, ONE DAY THESE RIGHTS WILL BE TAKEN AWAY. Andrew St.Pierre White Andrew St.Pierre White Andrew is one of the world’s most prolific 4x4 and overland writers and film-makers. This book is his 15th on the subject. Born in England, having lived most of his life exploring southern Africa, Andrew’s books, DVDs and TV programmes are known on five continents. His web site, 4xoverland.com, is one of the world’s oldest and busiest dedicated 4x4 web sites. His other professional activity is making TV documentaries and hobbies include flying light aircraft and gliders. Andrew lives in England with his wife Gwynn and three daughters, Stephanie, Erin and Kate. Contents 1. FoUR-WHEEL DRIVe 06 This chapter covers the fundamentals of four-wheel drive. Many technical questions on what makes a good, or bad 4x4 are answered here. 2. 4x4 VeHICLES 46 The 10 golden rules of selecting a 4x4 are followed by a comprehensive guide to 4x4s suitable to off-road driving and expeditions, new and old. 3. 4x4 ACCESSORIES 120 Half the fun of 4x4 is adding accessories to our vehicles. From bull bars to fuel tanks, turbo-chargers to suspensions. 4. WHEELS AnD TYRES 152 Tyre selection and the technical details therein. Includes other advice such as spare wheel location, repairing a puncture and tyre index tables. 5. 4x4 DRIVInG 168 From the basics of using four-wheel drive transmissions to tyre pressures and then detailed, easy-to-follow off-road driving techniques. 6. 4x4 ReCoVeRY 198 Going off-road means getting stuck now and again. Select the right recovery equipment and learn how to use it effectively. 7. TRAILeRS AnD TOWINg 228 Towing trailers is more complex than it first appears, especially off-road and on gravel. 8. OVeRLAnD EXPeDItIONS 240 Expeditions mean selecting, buying, testing, packing and using gear. The subjects and equipment discussed are wide and varied. 9. MAINTENAnCE AnD BUsH RePAIRs 284 Maintenance and breakdowns are a vital part of expedition life. 10. NAVIGAtION AnD CoMMUnICAtION 300 GPS know-how, compasses, maps and radios discussed in detail. WeLCoMe to tHe 4xoVeRLAnD You may legally duplicate this electronic file. You may legally share this electronic file. the contents are a guide to the subject, and the expressed opinion of the author. Any information found within, and applied, are at the reader’s/user’s own risk. You MAY not change, alter or edit any part of this book. You MAY not use or extract any part of this book in any form, including magazine, Internet and other publications, without the written consent of the author. You MAY not print this book. Please respect the work of the author. Register your copy of this book at 4xoverland.com Receive FRee yearly updates of this book Receive a FRee trial membership to 4xoverland Download FRee 4x4 training videos Download FRee 4x4 overland tV shows Go to WWW.4xoVeRLAnD.CoM 8 four-wheel overland 1. FOUR-WHEEL DRIVE 9 1.FoUR-WHEEL DRIVe 10 four-wheel overland 4x4 or 4x2? NEGAtIVe PeRCePtIONS ENGINES tRANSMISSIONS GRoUnD CLeARAnCe AnD SUsPENSION eLeCtRONICs MoRE TO CONSIDeR BUYInG PRe-oWNED 1. FOUR-WHEEL DRIVE 11 WHAt Is FoUR WHeeL DRIVe? In all of the motoring world, a higher percentage of buyers become dissatisfied with their choice after buying a 4x4 than any other vehicle type. The tricky part of choosing a four-wheel drive vehicle is that modern off-roaders have dual personalities. Many are required to cruise economically and comfortably and when the road ends these same vehicles are asked to climb hills more suited to a mountain goat. Armed with insight as to how vehicles are designed to cope with these demands is of significant advantage to the buyer and operator. 4x4 or 4x2? “A 4x2 with axle differential lock can do almost as much as, and can go just about anywhere that a 4x4 can go”. This statement, often used as selling hype on the showroom floor is untrue and misleading. The difference in the off-road ability of a high-clearance 4x4 and a similar 4x2 with axle differential-lock is dramatic. The difference in the off-road ability of a high-clearance 4x2 with differential-lock and a similar vehicle without differential-lock is also dramatic, but only under specific conditions. Why are these differences so vast? Half the load, double the traction A 4x2 transmission means that of the four wheels on the ground, two are driven. Therefore, 100% of the tractive force necessary to push the vehicle is divided between these two wheels. Add two more driving wheels and things change dramatically. The tractive force is now divided amongst four wheels instead of two, halving the load on each wheel and thus doubling the effective traction. So in the laboratory, when the terrain under the vehicle remains constant, a 4x4 has twice the tractional ability of a 4x2. In the real world with rocks, grass, mud and sand challenging the grip of the tyres, things get even better for the 4x4, because the tractive qualities of the ground under each wheel are never equal or constant. For the purposes of this discussion, we will assume that the 4x2 has its rear differential locked and the 4x4 has no axle differential-locks. For our 4x2 to move, one of its two driving wheels must lie on terrain that will support the tractive effort. If not, both driving wheels will spin. In the case of our 4x4, it will move if any one of the four wheels has 12 four-wheel overland enough grip to support the tractive effort, with the following proviso: The dual-personality of a 4x4: Asked to should one of the wheels on any one axle lose 100% of its traction, cruise the highways the demand for traction is transferred to the other axle. For a moment in comfort and the vehicle effectively becomes a 4x2, until conditions change. As the economy one day, vehicle moves, conditions change by the millisecond, during which then asked to tackle a mountain rockfall the time traction is transferred from one wheel to another and from one next. What amazes axle to another. So, not only is the traction load split between left and me is the skill of the right wheels, it is simultaneously split between back and front. vehicle designers and engineers: So many Another way to illustrate how these vehicles differ in ability is to ask 4x4s built today can do both things so well. how each driver feels about driving over difficult terrain. While the 4x2 Below: The Range driver moves along the trail he is concerned that conditions are going Rover was won of the to get too difficult for him to continue. The 4x4 driver, on the other first vehicles that did hand, is excited about the prospect that the trail will get tougher, and not really well. Bottom: Land Cruisers that his or her vehicle will be challenged. Yet another way of looking and Hilux on the at it is to count the broken differentials that litter 4x4 trails. These coastal plateau of shattered components mostly come from 4x2s that, having completed Angola. 80% of the trail and were asked to overcome a steep rocky climb that stood between them and an overnight stop. And so the driver, loath to turn back, throws caution and good sense to the wind and attacks the slope like a test pilot attempting a new climb-to-altitude record. The reason for needing to rush the slope is the lack of low transfer gearing. Without it, the vehicle has no choice but to race. The trouble is, the high speed means that wheels bounce violently and the vehicle loses even more traction: it’s a vicious circle, the more speed, the less traction, which means that more speed is needed and so on. However, low transfer gearing means that the steepest, roughest slopes can be taken slowly, carefully and with little or no risk of vehicle damage. GIACOANGELINI 1. FOUR-WHEEL DRIVE 13 Extra low gearing is as essential to an off-road machine as is all-wheel drive. Without it, it’s not an off-roader, nor is it particularly good at heavy-duty pulling: for example, low gearing saves clutch wear when pulling trailers up steep pull-aways. Full-time four-wheel drive It has been suggested that a 4x4 with an open centre differential is, by virtue of having three open differentials in the system, driven by only one wheel at a time. This I believe is misleading. In ideal traction conditions this type of vehicle is being driven by all four wheels simultaneously, with 100% of the traction effort being split 25% each.