How does my ADV styled topbox affect my fuel mileage?

[Theshnizzle]

I have the Givi Outback trekker topbox which when weighed seems to come up at about 13.5 lbs. I also have the E36 Givi which comes in at about 7.5 lbs weight. The E 36 has a lower more rounded profile than the Givi Outback Trekker square topbox. A twofold question....How much does that topbox weight affect fuel mileage and shape of the box as well.

I have a 3 set of Aluminum bags and I seem to waffle about taking the alum topbox due to the weight. I am a smaller, weaker rider and I am very cognizant of where the weight goes behind me and I am not a fan of overloading the rear of the bike especially if it's going to be up and away from the lower center of gravity.

Any thoughts on this?

 

[jggassert]

I have aluminum panniers and a top box. Have seen no remarkable drop in MPG


Primum non Nocere

 

[L.B.S.]

The highest mileage I've ever recorded, (over 80 US mpg) came with an overloaded bike complete with Trax 37 litre aluminum panniers and 38 litre top box. Me in gear is around 250 lbs. give or take.

After that trip (it was the first with a big metal top box) I did vow to not put as much stuff in it on next excursions, as I did notice the weight back there. Now I just use it for really lightweight stuff or my camp kitchen/food supplies.

 

[drdubb]

You'll have more of a drop at highway speeds. Drag increases exponentially with speed.

 

[ld_rider]

.How much does that topbox weight affect fuel mileage and shape of the box as well.

Neither would be measurable in the real world. The top box sits behind you so it isn't even in the windstream. The additonal weight is insignificant.