hauling kayak

[mtsoxfan]

I'm heading up to VT Wednesday to view some property, and have some fun on Lake Willowby (sp) I'm bringing my kayak and was wondering if it makes a difference if I have tonneau cover on or off for gas mileage. 9'6" kayak will need tailgate down.

Sponsored

 

[khyros]

I'm heading up to VT Wednesday to view some property, and have some fun on Lake Willowby (sp) I'm bringing my kayak and was wondering if it makes a difference if I have tonneau cover on or off for gas mileage. 9'6" kayak will need tailgate down.

You're going to get all sorts of non-scientific answers here, and maybe someone will site some data on generic truck aerodynamics...

But from a practical point of view, a tonneau cover costs end users ~$300 for an entry level one. Which means it would cost Ford no more than $150. If there was any significant fuel economy difference that could be realized with a tonneau cover, they would absolutely make this a standard feature so they could capitalize on the fuel economy credits (not to mention the window sticker number increase). The fact that no OEM does this for any of their vehicles, means to me that it really doesn't matter.

 

[ElSolo]

I'm heading up to VT Wednesday to view some property, and have some fun on Lake Willowby (sp) I'm bringing my kayak and was wondering if it makes a difference if I have tonneau cover on or off for gas mileage. 9'6" kayak will need tailgate down.

Reminded of this gem from MythBusters.

 

[Deleted member 1634]

It certainly does make a difference, everything does. But it's within the noise of all the other variables that affect mileage and aerodynamics. In the end, I wouldn't worry about doing it for mileage reasons one way or another.

 

[SRAces]

Everything is based on resistance. Wind direction, hills, etc. I don't think the Tonneau cover makes much (if any) of a difference since it is not in direct line of the air the truck is pushing through. The tailgate up or down has been discussed for years with no clear determination as to whether it truly affects fuel economy. I watched the video above as well.

I can tell you from my personal usage, I do not see any appreciable difference in fuel economy hauling a single kayak in the bed of the Ranger versus no kayak in the bed. I have had a tonneau cover since day one. Now if I pull my dual jet ski trailer with 2 kayaks I see a significant drop in fuel economy. At least 3-4 mpg. I am sure that is a factor of the weight being pulled and the wind resistance created by the trailer and the 2 kayaks. Just my thoughts.

 

[Ranger8729]

From a single trip standpoint, it will make no noticeable difference in mileage. If this were an everyday occurrence it would be a factor. From my personal experience over a few hundred thousand miles, a tonneau does make a difference. The 87, 96, and now 19 all get better unloaded daily hwy mileage with the cover on (avg 1.5 mpg better). YMMV.

 

[Deleted member 1634]

Everything is based on resistance. Wind direction, hills, etc. I don't think the Tonneau cover makes much (if any) of a difference since it is not in direct line of the air the truck is pushing through. The tailgate up or down has been discussed for years with no clear determination as to whether it truly affects fuel economy. I watched the video above as well.

Air resistance is a big deal for sure. It's also a lot about maintaining laminar flow over the object, vehicle in this case, as well. So a nice sweeping continuous surface with a long taper at the rear are ideal to keep the air attached to the surface. That's why teardrops are one of the more effectively aerodynamic shapes. And why trucks with the blunt step between the rear window and bed aren't great. A tonneau will help a little bit to remedy that, but not much.

From a single trip standpoint, it will make no noticeable difference in mileage. If this were an everyday occurrence it would be a factor. From my personal experience over a few hundred thousand miles, a tonneau does make a difference. The 87, 96, and now 19 all get better unloaded daily hwy mileage with the cover on (avg 1.5 mpg better). YMMV.

Agreed. A tonneau does help. I noticed a similar ~1mpg increase with adding the tonneau. And even more interestingly I've noticed an additional ~2mpg increase on top of that by adding the topper! Might just be that it extenuates my already eco driving style, but it does follow the science I mentioned earlier of maintaining a more laminar flow over the vehicle. There is still a blunt edge at the very rear, which means it could be better, but still happy with the results I'm getting.

 

[mtsoxfan]

Thanks. Maybe I phrased the question wrong. I do have a tonneau cover. I was wondering if it made a difference whether it was open or closed with tailgate open. I have watched many videos, and the tailgate open (without tonneau) does decrease mileage.
I drove to VT with tonneau cover closed, with kayak outback and got my normal mileage. I figured that would be better than tailgate closed and kayak sticking up like a kite.

Sponsored