Article from 4WDing Australia.

Roof racks are a fantastic accessory for a 4WD, especially if you are running low on space. There are lots of options out there though, and it can be a mine field in choosing a roof rack that does what you need it to. In this post, we cover the 10 things to consider when buying roof racks for your 4WD.

Weight

In my opinion, by far and away the most important thing to consider when getting a set of roof racks, or roof bars is their total weight. Weight up high is not good for anything, especially when you are off road. Roof racks can range from a couple of kilograms for the light duty roof bars, through to about 70kg for a full size, steel roof basket.

The weight of your roof racks is directly related to how much gear you can carry up top, and how badly your vehicle will handle off road. The weight of your roof racks is also the biggest factor in keeping your vehicle loaded legally, which we go into further below. To find out more about weights, check this out – Roof racks; are you overloaded?

Roof racks

What do your roof racks weigh?

Mounting position

When you get roof racks, you need to choose a mounting position. If you have a Ute, this could be on the Canopy, or it could be on the front part of the vehicle. You can mount them forward, in the middle, or right at the back, and there are different benefits for each configuration.

Even on a wagon, its important that you consider aerodynamics, axle load and how it will affect the vehicles handling. The further forward the more likely the roof racks are to catch the wind, and cost you extra fuel. However, if you put them at the rear and you have a well loaded 4WD, its easy to exceed the rear axle capacity and that’s no good either.

Roof racks forward or back

Are the roof racks far forward, or back?

Type and Size

Roof racks start off at two light weight rails, and work their way to full sized roof cages. The idea here is to purchase the type, and size that suits your requirements. If you just want to mount a solar panel, or carry a few fishing rods your requirements are going to be vastly different to someone who wants an oztent, gas bottle, two jerry cans, a couple of swags and camp chairs.

You can get a number of different size and strength rails, and then cages. Some are flat platform racks, and others have edges around one or more sides.

The type and size of the roof rack needs to reflect what you want to carry. If you are using rails, you need the spacing to be right for what you are carrying. For example, carrying an Oztent means you need a decent amount of support, and if you had them too close to each other you’d risk the tent being bent in transit.

Fishing rod on roof racks

If you only need roof racks for an awning and fishing rods options are much greater

Tie down points

Anything that goes on your roof racks needs to be tied down well. This is especially the case if you are going off road, as the extra force applied to anything sitting on your rack when you are bouncing around is significant. This in turn means you need suitable attachment points to do your tying down.

In many cases this is just a series of holes that you can hook into, but some racks today have sliding eye bolts that you can move around as required, or rails down the side, or anything in between.

Lifting lugs

How can you tie items down safely?

Material

Most roof racks will be steel, or aluminium. Unless you are just talking about a couple of rails, I would not get anything made of steel. It’s simply too heavy to be worth using. You will pay more for aluminium, but it won’t rust and cause you a headache in the future. The aluminium racks have come a long way, and you can get some seriously strong roof racks in aluminium that weigh very little, and look fantastic.

Solar on the roof racks

Light weight racks and a flush mount solar panel

Durability

I’ve seen some pretty shabby roof racks. If they are steel, and the paint job isn’t excellent, you will end up with rust forming, and it can be a huge problem. I’ve seen racks drop rusty water onto the roof of a nice 4WD, and cause rust spots on that too.

Ideally, you want something that is bare aluminium, or has been properly powder coated. If its got mesh, and you plan on attaching, or walking on this, expect it to break after time. Our 80 Series had the gate style mesh on the bottom and there were pieces that had cracked from years of use.

Our roof racks

Our old roof racks had bits break from walking on it so much

Roof Mounting attachments

Now, onto a subject that has had a fair bit of sensitivity attached to it recently. Roof racks need to be securely mounted to your 4WD, and that can be done in a number of ways. In the past, most 4WD’s had gutters that the roof racks would physically clamp to. A lot of manufacturers have gone away from the old style lip gutter, and roof racks are physically fixed to the roof of the vehicle.

You can get roof racks that clamp around the roof, into where the door shuts, but you’ll find these are not rated for off road use. The exact method of attaching to the vehicle roof varies considerably too. Some use the factory nutserts in the roof, others rely on rivets, and the most heavy duty versions today use bolts going through the roof of your 4WD. This means the roof liner needs to come away, and a bolt goes right through the roof.

Mounting roof racks

Are the roof racks mounted in a rock solid way?

Roof ratings

Every 4WD comes with a roof rating. This is specified by the manufacturer of the vehicle, and in general you’ll find two ratings – static and dynamic. This simply refers to the amount of weight the vehicle is legally allowed to carry on the roof in its non moving position, and then when it is moving.

The static weight is important for those who want to use a roof top tent, as you might add an extra 180kg onto the roof if you are sleeping in it with your partner. These roof ratings are set by the manufacturer, and cannot be changed. You can’t fit a rack with a higher capacity and then assume its capable of doing more; the maximum capacity of the roof is set by the OEM.

Car roof rating

Every 4WD has a maximum roof capacity determined by the car manufacturer

Rack ratings

The next rating that is critical is the rating of the rack. That is, what can the rack legally carry before its considered overweight, and likely to do damage? Things get interesting here, as you have on road rack ratings, and off road rack ratings.

This makes sense, as the forces applied when you are off road are significantly higher than what you’d experience on the road. Some racks might be suitable for 75kg on road, and only 30kg off road (minus the weight of the rack). Each roof rack manufacturer has their own way of specifying this, and I’ve seen some that just have one rating for both on road and off road use.

Tracklander roof rating

What can your roof racks carry on and off road?

Height off the roof

Another thing that a lot of people don’t seem to think about is the height of the racks off the roof. This is important for a number of reasons.

The higher your racks are off the roof, the more fuel you’ll use. This is where wind deflectors can come in handy.

The next major issue is the higher your racks sit off the roof, the worse your centre of gravity is going to be. I’ve seen people with roof top tents that start 250mm off the roof of their 4WD’s vehicle, and that is a major problem. Keep the racks as low down as possible, and you’ll be best off.

The higher the racks the worse it looks too, and its particularly obvious when you bolt a generic roof basket onto roof rails that are already high off the roof.

Roof racks low down

The lower the racks to the roof, the better