Fuel consumption & Roof Racks

I just rigged up a pully off the shed roof, 10 mins it was off and hanging up...

Well worth it. Took 1 roll of nylon rope and 4 large hook things from Mitre 10. They are heavy aint they!

I didnt measure the difference as in MPG, but I know I got more klms to work without it on than with it. Also the speed difference is very measured.

David, after a recent trip that returned worse fuel economy than expected, I experimented with and without the rack (empty and with wind deflector). I reckon it has added about 1 litre/100 kms, or roughly 6 to 7 %.Smile, you're on ExplorOz
Rohan (Sydney - on the QLD side of the Harbour Bridge)

I measured NO difference at all between the two but i had a patrol with 4.2 efi which was over 20 litres per 100klm no matter how i was set up...._____________________________________________

_____________________________________________

I have a Hilux Surf with Thule Roof Racks (the rounded ones instead of the square edge ones). It's the 1KZ-TE turbo diesel with Intercooler (same as the current Prado). I measure the L/100km every time I fill up and I couldn't find any noticeable difference to the figures that I had before I put them on a few months back. So I just keep them on the roof permanently.

Also, there is absolutely no wind noise at all coming from the roof, even when driven up to 120km/h or so.

In July I went up to Mt Buller (VIC) for a snow trip. With 4 people on board, a full load of luggage, plus skis in a ski bag on the roof rack, the fuel economy was 9.8L/100km !! That's including going up the mountain and down (probably 10km to go up the winding road to the top and them another 10km back down).

If the cross bars on your roof rack are the rounded ones, they should be OK. But at least I know Thule is excellent.

gday david.
with out roof rack we get about 370-400ks to 90ltr of gas gq.
with racks we lose about 50ks to a tank.
thats empty when im to slack to remove it.
now that its opf im to slack to put it back on so just make stuff fit in car lol—~‘¬‘¥•s’B

My ex Cruiser and new Patrol seem to lose 1 km per litre with the rack on. Down from about 7km to the litre to 6 ish.

Hilly

I've got a 80 series petrol 1fzfe and have run a roof rack full time for the last 50,000km why ? without rack 5.17 km/litre ,with 5.00km/litre
hell thats 19/100km v 20/100 km for the technically correct .
above figures are empty running
same roof rack on old 60 series diesel went from 4litres/100 into a headwind thru central QLD with tinny on roof to 10km /litre on OTR to cape loaded to hilt . all depends on how hard(read fast) you want to push into the wind.
for a couple of bucks a week IMHO why go to the effort of removing /reinstalling with inherent storage prob to save stuff all.
Howard

I have a GU 4.2TD, the roofrack is an ARB full lenght.

My fuel economy without the rack is about 11.5 to 12 L in 100kms.

The roof rack increases fuel usage by 2 litres per 100kms on the highway and 1 L per 100kms in the city (with some highway driving).

I too made up a pulley system at home but the ARB rack is very heavy so rope was not enough.
I used a boat winch attached to the wall with a pulley on the steel beam, even the square (1 inch diameter) steel beam warps when its pulling the rack!

I only put the rack on when I absolutely need it, ie: long trips that require an extra spare etc.
Will

G'day David,

I had the alloy TJM roof rack on my GU2.8lt TDI Patrol.

No wind deflector up front.

Wind noise and drag was significant, and fuel consumption worsened by 2-3 litres per 100 kilometres.

Great roof rack though :-)

Cheers,

Luke.

Reading through the replies to your question, no one has commented on the larger tyres you say you have fitted.

How much bigger are they? Bigger tyres will generally cost you more in fuel because they are 1. heavier 2. the engine has more resistance from the road to push against.

Constant highway use may see a slight improvement in economy over smaller tyres but when you knock it all together..city...country....off road, I think it is safe to say you would use a bit more fuel with the bigger tyres. Especially in stop start situations where the engine has to work that little bit harder everytime you take off.

I have seen similar comments in previous threads.

Just a thought.

cheers

I have several tens of thousands of kilometers worth of fuel consumption data for a HZJ75 troopcarrier, with and without roof racks, and with roofrack plus a 3.5 m tinny. The differences the various roof attachments make to fuel consumption is trivial compared to driving, road and wind conditions. So unless you are travelling around at 120 km/h or so, the roof rack may not the major cause of your fuel consumption 'problem'. I suggest that the tyres might be worth looking at, as some of the others have done.