> Insurance Getting on top of things early... We all love a good roof rack (well OK, I do). So what if they ruin the streamlined shape of your vehicle, increase fuel consumption and affect vehicle stability … then there is the fall factor when climb- ing up on top to load and unload stuff: more than one good man has fallen from a roof rack. At the end of the day the reality is, generally just before you are about to head off, whatever you can’t fit inside gets chucked on top! Roof racks range from the simple cross- bars attached to your roof rails (you do have roof rails don’t you?) to complex welded basket structures that bolt directly to your roof like my ARB aluminium deluxe roof rack (which I think is awesome btw). What you choose will depend on the type of vehicle you have and what you need the rack to do. ... but here’s the thing, when loading up, it’s vital you know how much is too much. The starting point is your vehicle’s roof load capacity: it’s listed in most vehicle handbooks. Most 4WD vehicles have very limited roof load capacity and around 70 kg and up to 100 kg being typical. These limits are static load weights but are based on dynamic conditions – whilst driving the car. It takes into account vehicle handling, rollover risk and dynamic loading.   Dynamic loads can be significantly more than static loads. So we know that the roof of your vehicle can hold a lot more than the load rating, because that rating takes into account hitting bumps and other stressful forces that take place when driving. This does not mean there is “room to move” when loading up your roof rack, for every extra kg added you could be effectively adding 5-6 kg’s of stress onto your vehicle. You should never exceed the manufacturer’s roof load ratings. It is very important to note that the roof load rating includes the weight of the rack. Some of the full-length steel racks I’ve seen already exceed many vehicles roof loads…without anything on them! If you know the weight of your roof rack you simply subtract that amount from the roof load rating to get the rack payload figure you’re allowed For example, if the rack weighs 40kg and the roof load rating is 100kg, you can stow up to 60kg on it. Racks are ideal for light stuff that won't have too much effect on your 4WD's centre of gravity. Swags and tents are bulky rather than heavy and rain and dust won't damage a well packed tent on a roof rack. If your roof rack is carrying a tent, poles, folding camping chairs and table, an unmounted spare tyre, empty jerry cans and a couple of small gas bottles, it's probably full. Loading It’s a good idea to streamline your load as best you can. Tapering the load profile from front to rear is beneficial. A wind deflector at the leading edge of the rack could improve the aerodynamics and a hard or soft cover will also aid streamlining as well as offer weather protection. It’s vital that anything in a roof rack is strapped down so that it can’t work loose and fall off. Gas bottles are notoriously difficult to strap down. They need to sit in mounting rings or chocks, so they can’t wander around on the rack floor. Non stretch ratchet straps are good for clamp- ing down gas bottles. Things like folding chairs and tables are easier to secure if they’re stowed inside canvas bags. It is also very important that the attach- ment screws are checked for tension as they can work loose when driving over rough or corrugated tracks. Loose screws result in damaged threads at best and a departed roof rack at worst. If you are considering fitting a roof rack to your 4WD or are about to load up your existing one, think carefully about what you plan to put up there. It might be best if it is the first thing you load and what you can’t put up top can go inside. Enjoy the journey! 28 JUNE 2019 TRACKWATCH