Two-up fuel consumption

[F14CRAZY]

http://www.fuelly.com/motorcycle/bmw/k75c/1987/f14crazy/307945

Using Fuelly I've tracked my brick for over 16k miles so I have a decent idea of how much gas it burns.

I've noticed that even at the same sustained speeds and on long trips (the kind where you exit the interstate, get gas the nearest station, hop back on the interstate, and keep going until gas is needed again) that mileage is typically 2-3 mpg better with my now-wife on board.

She's an additional 104 lbs or so on the bike. Does she improve aerodynamics enough to more than compensate for the additional weight?

[Scott_]

I've also notice similar over the years, no decrease in mpg while riding with 2-up either.

[Bokobob]

I can't address your question, although I find this revelation most interesting. 

[Snowman]

I have a long trip coming up and need to borrow your wife.  :riding:

[johnny]

my now bucket of weed butter weighs more than 104 pounds...

[F14CRAZY]

I wondered if its because she takes up some of the space between me and the top case.

[TrueAce]

The aerodynamic "bubble" created by the energy of the bike allows her to ride w/o creating additional resistance. Her extra 100 lbs. Are incidental. Now we should ask other brickers who have heavier "cargo" to report so we can scientifically determine the weight at which fuel consumption increases, thereby necessitating replacement of said cargo.

[The Mighty Gryphon]

The aerodynamic "bubble" created by the energy of the bike allows her to ride w/o creating additional resistance. Her extra 100 lbs. Are incidental. Now we should ask other brickers who have heavier "cargo" to report so we can scientifically determine the weight at which fuel consumption increases, thereby necessitating replacement of said cargo.

You sure you want to go there???

[drut]

I have never noticed any difference in mpg with passenger on board,there may well be one but on my bike it can't be much.

[frodef]

I suppose in theory a passenger or other extra weight should only decrease mpg if one only rides uphill, and never back down again. Neither wind drag nor roll resistance should be affected much.

[F14CRAZY]

The aerodynamic "bubble" created by the energy of the bike allows her to ride w/o creating additional resistance. Her extra 100 lbs. Are incidental. Now we should ask other brickers who have heavier "cargo" to report so we can scientifically determine the weight at which fuel consumption increases, thereby necessitating replacement of said cargo.

Perhaps some modification or restoration should be considered before replacement

[TrueAce]

Good point.....modification prior to replacement would be in order. All MotoBrickers, please submit modification designs to your respective Cargo to meet targewt parameter of 104 lbs. Post photos of modifications received to your face!

[Brad-Man]

Or possibly other parts of your anatomy -  oh wait - pass on that...

[vintagemilano]

I haven't noticed any decrease being two up. Perhaps you are getting an increase just because you aren't as aggressive in driving style with the missus on board.

[Elipten]

Now there is a thought and most likely cause.

[F14CRAZY]

I've thought about it but I've monitored mileage while on open interstate and at the same sustained speeds. I might accelerate on the on ramp a little more gently but that's one acceleration event up to cruise speed, which I hold until gas is needed again

[jakgieger]

Perhaps the more accurate test would be putting 104 lb in the saddlebags as "cargo".  I doubt it is the aerodynamics.  Me personally, it would be driving style :hehehe.  When my "cargo" is on the bike we definitely go easier...

[HYPERR]

I don't know about you but I ride very different with a passenger.  I don't accelerate as hard and tend to ride much more conservatively.  Perhaps this is why you are getting better mileage with your wife on the back?

[drut]

" I don't know about you but I ride very different with a passenger.  I don't accelerate as hard and tend to ride much more conservatively.  Perhaps this is why you are getting better mileage with your wife on the back? "

You have a good point and follow the same riding principles as me re:riding with passenger but I cannot tell where you are from in your profile.Here in the UK I tend to mainly travel shorter trips(av: about 75-130ml)than folks in the USA so my trips don't cover the miles to average out the variables so well.I guess differences in terrain,how busy the road traffic is and headwinds make more difference than carrying a passenger.