How much do Roof rack baskets affect MPG

[Tozan]

I am considering building a full roof rack basket on my Tahoe anyone have data on how many MPG I might lose from this?

I keep try to keep my MPG reasonable but I keep adding more stuff to it... lol Right now with all my modifications I only average between 14.5 to 19 My rig and two people weighs in at 6800 pounds right now.

 

[wjburken]

My rig and two people weighs in at 6800 pounds right now.

Is that before or after you clean all the mud off?

I would guess depending on what you do on the leading edge and how tall you make it, you shouldn’t be surprised to lose 1-2 MPG.

 

[swathdiver]

I think it's more like 4-5 mpg lost, a basket on the hitch will cost less, if any, loss in mpg. Won't look as cool and gets in the way of the back hatch. Too much stuff up top raises the center of gravity and will make her tipsy. Roof weight limit is about 200 pounds if memory serves.

 

[Tozan]

The hitch already has a spare tire on it. I don't really want any more stuff back there plus a rack on back would get knocked off, smashed or possibly get me hung up or stuck... I am mounting a 270 degree awning on it and was going to put a rack on so I could mount the awning to it... The other option is just weld up a mounting arm for it.

This is a daily driver but on weekends it is an Overlander for camping and exploring. Two weeks ago we did 3 hours off road at night with shifting into 4x4 low more than a few times before getting to our campsite. The next day we did another 50 miles to our next camp site.

 

[Tozan]

I am thinking of building the bottom of the basket so it is 1/2 off the roof unloaded and if it sits on it when loaded it should be no big deal. The side rails I am thinking will actually be sitting on the factory side rails to keep the overall profile real low. The front and rear bars will at best be about 4 or 5 inches above the roof surface maybe slightly higher than my custom cross bars I made. Hopefully this will keep my MPG close to what I was before...

As a side note I went from 315/70x17 tires to 35x12.5x17 weight difference between them was only 5 lbs per tire and width is actually a 1/4 inch less and the tire is only .2 in taller but, my MPG on the highway dropped by almost 2 MPG on the average... Funny how some things can make such a difference...

On the up side when off road most of this makes very little difference in MPG..

 

[swathdiver]

On the up side when off road most of this makes very little difference in MPG..

Same will be true for the roof top basket and all the stuff in it, just watch the weight so she don't keel over.

 

[Tozan]

I was walking by my Tahoe the other day and it dawned on me that the top of my hood is exactly shoulder high... lol It's not to top heavy with all the gear in it.

 

[Neill Campbell]

I am considering building a full roof rack basket on my Tahoe anyone have data on how many MPG I might lose from this?

I keep try to keep my MPG reasonable but I keep adding more stuff to it... lol Right now with all my modifications I only average between 14.5 to 19 My rig and two people weighs in at 6800 pounds right now.

View attachment 228327

I run a roof rack and often have up to 3 bikes on it. It makes nearly no difference in MPG. And those, while not heavy, produce way more drag than a basket with or without fairing.

As for wheel weight, rotational weight is far more impactful than non-rotational rate.

And while your new wheels may be more narrow they likely have a larger contact patch on the ground. That is where friction is created and rolling resistance.

So add the roof rack and go nuts with it.

Great looking rig. BTW, what else have you done to it? How much is it lifted?

 

[mountie]

As long as the leading edge of what's stored on the roof rack isn't a square box shape, the MPG will not be much of a difference.

Get some peel -n- stick vortex generators along the front roof edge may "spill" the air better. If you worry about aero- caused MPG.

 

[Tozan]

I run a roof rack and often have up to 3 bikes on it. It makes nearly no difference in MPG. And those, while not heavy, produce way more drag than a basket with or without fairing.

As for wheel weight, rotational weight is far more impactful than non-rotational rate.

And while your new wheels may be more narrow they likely have a larger contact patch on the ground. That is where friction is created and rolling resistance.

So add the roof rack and go nuts with it.

Great looking rig. BTW, what else have you done to it? How much is it lifted?

Actually the new tires measure out to be less that the old ones but they are supposed to be 6# heavier. I will need to actually weigh a new tire to see what the real difference is. I think I am going to check into a set of racing rims to see if I can loose a few pounds there.

I am running a 4 in lift.