Mike replied:

Thomas, if there is nowhere else to put it, then that's where it has to go. As you use fuel, empty your jerry cans into your tank, so the weight is up there for the shortest time. Your rack must also be in top condition. As for the extra weight on top, adjust your driving to suit. Happy trails, Mike.

Kim McFarland replied:

I crossed the Simpson Desert last year with three jerry cans on the roof and although I didn't experience any breakage, the rack did move about 50mm from it's original position. I did have problems with expanding jerry cans (through the heat) and had to regularly vent them. Check your owners manual. The maximum weight that can be loaded on the roof is usually listed there.

Kim McFarland replied:

I crossed the Simpson Desert last year with three jerry cans on the roof and although I didn't experience any breakage, the rack did move about 50mm from it's original position. I did have problems with expanding jerry cans (through the heat) and had to regularly vent them. Check your owners manual. The maximum weight that can be loaded on the roof is usually listed there.

Colin Johnson replied:

try leaving some stuff behind first - there ia lot of 'rocking and rolling' crossing sand dunes !full jerry cans on the roof is a last resort. I used a rack on my '91 'L' Subaru for a CSR trip last year but it had 6 foot supports and it only carried a spare wheel, camp table and a tent. I carried 2 jerries of water and 2 jerries of fuel strapped to a steel false floor in the middle of the car. PS - all our jerries were left full, in the sun for a week, to make sure they didn't leak !!

Michelle - ExplorOz replied:

Thomas, your roof rack should have a load rating. eg. our Rhino Roof Rack on our 80 series is rated to 100kg. Never consider overloading it and the rest of the advice here from other readers is all relevant. One thing to note - the roof rack and load will affect your fuel consumption/economy quite significantly. Another thought is to use the roof rack but to shift the packing and consider putting the 2 extra jerrys (or whatever) on the floor of the vehicle and put lighter, bulky items on the roof rack. That would be safer compromise. Fuel really should be avoided on the roof rack - the extra weight on the roof really throws out the balance and you are more prone to roll overs.

John R. replied:

Thomas,
I have travelled with roof racks on different vehicles and carried fuel in jerry cans. Try to keep the weight between the axles, ie. don't put them right at the rear. I generally carried mine near the front of the rack in the middle. I used a sheet of ply and/or cardboard or an old foam sleeping mat to provide some padding. Ensure the rack is secure - I found the racks with full-length gutter supports the best. Some racks/roofs are rated to 75 kg - check your manual and rack supplier's limits.
You can cover the jerries with a silver-coloured tarp to minimise heat. Under no circumstances would I carry fuel inside the vehicle - regardless of type. Hope this helps.

Ray replied:

Thomas trhe problem is not the weight that the roofrack will carry but the weight that the brackets can hold under severe braking that sets the limit.There have been many cases of roofracks landing on the bonnett under severe braking. If you have to carry fuel, empty the jerrys as soon as you have space in the tanks for each one