car top carrier - R-pod Owners Forum

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hogone

Senior Member

Joined: 09 Apr 2013
Location: St. Louis
Online Status: Offline
Posts: 1060

Topic: car top carrier
Posted: 31 Jan 2017 at 5:07am

thoughts. planning on heading to florida latter part of march. i have a carrier (hard plastic wider shorter version that has a slight elevation from front to back vs the long narrow one). going to attach to back of camper shell. think that will have any positive effects on drag and increasing gas mileage? actually am doing it just to do it and find out. hogone

Jon & Pam
2013 RP177
2010 F150
2017 HD Streetglide
2009 HD Lowrider
CHEESEHEAD

StephenH

podders Helping podders - pHp

Joined: 29 Nov 2015
Location: Wake Forest, NC
Online Status: Offline
Posts: 6418

Posted: 31 Jan 2017 at 7:35am

I think it would depend on whether the carrier's top was angled so that the air flow off the top of it was aimed at the top of the R-Pod. If it does not have a sufficient angle to get the airflow to the top of the R-Pod, it likely would not do as much good.

I'm trying to figure out how to attach the AeroPlus to the roof rack on the Nissan Frontier we purchased. The rack is sufficiently different that it isn't just a matter of unbolting it from the Escape's crossbar and bolting it to the Frontier's cross bar. I likely will need to custom make some shims to make it work.

StephenH
Happy is the man that findeth wisdom,...

ouR escaPOD mods
Former RPod 179
Current Cherokee Grey Wolf 24 JS

Blue Highways View Drop Down

podders Helping podders - pHp

Joined: 20 Sep 2016
Location: NC mountains
Online Status: Offline
Posts: 86

Posted: 01 Feb 2017 at 9:28am

Heh, Jon, I am leaning toward using your carrier (even if it is not positioned at a perfect up-angle). It still will have a dispersing influence on the air turbulence while you're in motion, as it will still break up the air vectors that normally dam against the Pod's frontal surface.

Stephen seems right on his point that the ideal condition of the carrier would be to redirect currents upward so that they over-shoot the lower, flatter portion of the Pod. You "could" try for that angle, but it might look weird to try to place the carrier in a forced tail-up position on your camper shell.

I'm thinking that because you picked (or have) the shorter, wider carrier style, that's the best shape to break up and reduce the strength of air currents enough so that you gain a benefit in lower wind resistance, especially when towing through a headwind. You could test m.p.g. on a 200 mile stretch, then add the carrier for a similar 200 mile stretch, and compare results, if you have a bit of a "physics" side to you.

Whether it makes a difference or not so much, you'll still get that great extra storage cavity for say, medium weight, less moisture-sensitive camping objects that would otherwise take up room beneath the truck topper. It's probably worth putting this carrier to work, as long as the cost of the needed brackets, cross bars and other pieces isn't discouraging.

When I used to have a Thule rack on my Century topper, Thule made flat metal mounting plates (with gaskets) called artificial rain gutters, which remain attached to the topper, and to those, you attach the rack's foot assembly.

My topper was gloss white, so I just pre-painted the rain gutter plates gloss white too, so when the rack was removed, the brackets were somewhat invisible. Systems may be different now, and some toppers come with an installed pair of parallel aluminum mounting rails up top.

Brad & Layli

'17 179 HRE

Western NC

10 Tundra w/ARE topper

(Yakima basket carrier mounted to only the truck body this time...negligible wind deflection, too far forward)

hogone

Senior Member

Joined: 09 Apr 2013
Location: St. Louis
Online Status: Offline
Posts: 1060

Posted: 01 Feb 2017 at 3:21pm

blue highways: thanks for the info and words of encouragement. ya, I kind of like having the extra storage for those items ill keep up there. I already have several racks on my shell, just need to adjust one of them to fit the carrier brackets; and will have easy access with the tailgate down. so no extra cost involved taking it. I will be posting results in the future!! hogone

Jon & Pam
2013 RP177
2010 F150
2017 HD Streetglide
2009 HD Lowrider
CHEESEHEAD

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hogone Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 09 Apr 2013 Location: St. Louis Online Status: Offline Posts: 1060	Topic: car top carrier Posted: 31 Jan 2017 at 5:07am
	thoughts. planning on heading to florida latter part of march. i have a carrier (hard plastic wider shorter version that has a slight elevation from front to back vs the long narrow one). going to attach to back of camper shell. think that will have any positive effects on drag and increasing gas mileage? actually am doing it just to do it and find out. hogone
	Jon & Pam 2013 RP177 2010 F150 2017 HD Streetglide 2009 HD Lowrider CHEESEHEAD

StephenH Members Profile Send Private Message Find Members Posts Add to Buddy List podders Helping podders - pHp Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6418	Posted: 31 Jan 2017 at 7:35am
	I think it would depend on whether the carrier's top was angled so that the air flow off the top of it was aimed at the top of the R-Pod. If it does not have a sufficient angle to get the airflow to the top of the R-Pod, it likely would not do as much good. I'm trying to figure out how to attach the AeroPlus to the roof rack on the Nissan Frontier we purchased. The rack is sufficiently different that it isn't just a matter of unbolting it from the Escape's crossbar and bolting it to the Frontier's cross bar. I likely will need to custom make some shims to make it work.
	StephenH Happy is the man that findeth wisdom,... ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS

Blue Highways Members Profile Send Private Message Find Members Posts Add to Buddy List podders Helping podders - pHp Joined: 20 Sep 2016 Location: NC mountains Online Status: Offline Posts: 86	Posted: 01 Feb 2017 at 9:28am
	Heh, Jon, I am leaning toward using your carrier (even if it is not positioned at a perfect up-angle). It still will have a dispersing influence on the air turbulence while you're in motion, as it will still break up the air vectors that normally dam against the Pod's frontal surface. Stephen seems right on his point that the ideal condition of the carrier would be to redirect currents upward so that they over-shoot the lower, flatter portion of the Pod. You "could" try for that angle, but it might look weird to try to place the carrier in a forced tail-up position on your camper shell. I'm thinking that because you picked (or have) the shorter, wider carrier style, that's the best shape to break up and reduce the strength of air currents enough so that you gain a benefit in lower wind resistance, especially when towing through a headwind. You could test m.p.g. on a 200 mile stretch, then add the carrier for a similar 200 mile stretch, and compare results, if you have a bit of a "physics" side to you. Whether it makes a difference or not so much, you'll still get that great extra storage cavity for say, medium weight, less moisture-sensitive camping objects that would otherwise take up room beneath the truck topper. It's probably worth putting this carrier to work, as long as the cost of the needed brackets, cross bars and other pieces isn't discouraging. When I used to have a Thule rack on my Century topper, Thule made flat metal mounting plates (with gaskets) called artificial rain gutters, which remain attached to the topper, and to those, you attach the rack's foot assembly. My topper was gloss white, so I just pre-painted the rain gutter plates gloss white too, so when the rack was removed, the brackets were somewhat invisible. Systems may be different now, and some toppers come with an installed pair of parallel aluminum mounting rails up top. Brad & Layli '17 179 HRE Western NC 10 Tundra w/ARE topper (Yakima basket carrier mounted to only the truck body this time...negligible wind deflection, too far forward)

hogone Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 09 Apr 2013 Location: St. Louis Online Status: Offline Posts: 1060	Posted: 01 Feb 2017 at 3:21pm
	blue highways: thanks for the info and words of encouragement. ya, I kind of like having the extra storage for those items ill keep up there. I already have several racks on my shell, just need to adjust one of them to fit the carrier brackets; and will have easy access with the tailgate down. so no extra cost involved taking it. I will be posting results in the future!! hogone
	Jon & Pam 2013 RP177 2010 F150 2017 HD Streetglide 2009 HD Lowrider CHEESEHEAD