Roof Rack Position
Submitted: Wednesday, Sep 14, 2005 at 21:10
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adsum
This subject has probably been discussed before however, I hope someone can provide some advice. I have an 80 series and have recently purchased a 2nd hand Formula Offroad roofrack (approx 1.8M long) prior to a trip through the Flinders and NW NSW. I have fitted the rack with the 1st footing is over the B pillar, however the 2nd footing impinges slightly on the passenger door. Any suggestions on the best position in regards to:
1. Weight distribution and stength ( intended load around 70kg including rack)
2. Least impact on fuel ecomony.
Cheers
Reply By: VK3CAT - Thursday, Sep 15, 2005 at 17:03
Thursday, Sep 15, 2005 at 17:03
A couple of things to consider.
At 1.8m long you don't have too many options as to where to locate it but common sense says to place the legs where there is the most support.
The 80 series roof / gutter set up is not flat. With my Rhino Racks (fitted to an 80 series diesel) I have a 10mm spacer on the front bar & none on the back & middle (Rack length is 1.5m). Although you can pull the rack down onto the gutters using the rack mounting clamps, this may / will place stress on both the gutters and the rack.
I have been experimenting with various roof rack setups for many years. I have found in my case that the rack is best located towards the back of the car. Also the rack should be as close to the roof as possible with attention paid to reduce air flow turbulence on the underside of the rack.
As for wind deflectors, I have tried various types with little if any improvement in economy. The latest attempt is a 150mm sewer pipe across the ront of the rack - can also be used for storage.
As a comparison, when I had a Rola rack & carry basket fitted & loaded, I found little difference in fuel economy from when running without any roof rack. This Rola rack was not strong enough for my purposes.
The Rhino rack, when first fitted, with 150mm legs, Unistrut 1.2 x 1.5m rack & a Racksack reduced average distance per tank fill (abt 130 litres) by about 200 to 250Kms.
Cheers Tony
AnswerID:
130258
Follow Up By: adsum - Saturday, Sep 17, 2005 at 20:07
Saturday, Sep 17, 2005 at 20:07
Tony,
Thanks for the advice, as usual I was in a hurry and did not notice the slight profile change in the gutters. The previous owner also used a large roof rack(indicated by clamps marks). Since your post I have noticed that the gutter over the passenger door has been pushed down, alas the damage has been done, but I will try to space or modify mounts. The rack has a wind deflector built into it, however the rack sits 120mm above roof line.
Thanks for your advice
Tony
FollowupID:
385037
Reply By: Member - John C (QLD) - Thursday, Sep 15, 2005 at 17:45
Thursday, Sep 15, 2005 at 17:45
Adsum,
As you can see we use a full length rack - 1.8m.
Used to put the rack as far as possible to the front to get some load off the rear and onto the front. The rear used to sag a bit.
Now have air bags in the rear so npw putting the rack as far back as possible by moving it about 200mm to the rear. (current photo)
Always try and pack the rack with a taper, small stuff at the front and bulkier stuff at the rear.
When it was forward noticed I used to get alot of insects on the front of the rack, now at the rear hardly any, so assuming that the air rising off the windscreen is no longer hitting the front of the rack as much. Used to reckon on the roof rack being worth about 2 to 3l/100k, depending on speed. Over 90km/hr make it 3l/100k. Now it is about 1 to 2l/100k at 100km/hr.
I still try and get the main supports over the B and C pillars, even with only 100 to 120kg on the roof rack.
AnswerID:
130261
Follow Up By: adsum - Saturday, Sep 17, 2005 at 20:18
Saturday, Sep 17, 2005 at 20:18
John,
Thanks for the info, sounds like I have placed my rack in a similar position, the previous owner fitted good
suspension and poly bags so I should be also able to push the weight back.
The problem appears to be related to damage to the gutters near the C pillar, will have to make some minor mods to the rack to gain a mm of clearance somehow, don't want to crack the paint work trying to straighten the gutters.
The extra fuel usage experienced by yourself, is better than I expected hopefully my 4.5 will be similar.
Cheers
Tony
FollowupID:
385043
Reply By: Willem - Thursday, Sep 15, 2005 at 18:45
Thursday, Sep 15, 2005 at 18:45
I have a 2m roofrack and have it sitting right back so that the rear of the rack is level with the rear gutter. The roofrack also has a perspex wind deflector. The difference in fuel consumption without the rack is 1.2litres/100km. Not much in the wash up but I have the roofrack tied to the garage ceiling at the moment.
I have a heavy duty OME
suspension on the GQ and the bit of weight on the roofrack(Oztent, spare tyre casing and other light stuff) makes no difference to the ride height.
I also find that having the roofrack as far back as possible I get no wind noise from it.
AnswerID:
130271
Follow Up By: adsum - Saturday, Sep 17, 2005 at 20:24
Saturday, Sep 17, 2005 at 20:24
Willem,
Thanks for the reply, likewise the rack lives in the shed when not in use, fuel is too expensive to waste. The common thread appears to keep the rack back out of the airflow as much as possible. The difference in ecomony also appears to be constant. My previous experience with racks (car based) was significant differences, I suppose that the cruiser is already pushing a large hole through the air, so a little extra has less impact.
Regards,
Tony
FollowupID:
385046