Archives

This morning Jeff (http://www.cleanmpg.com/forums/member.php?u=1429) and I were talking about how to measure week to week (instead of tank to tank) MPG on a motorcycle. Well I think we may have come up with an idea. WEIGHT IT. The basic idea is to weight the bike (without the rider) before you leave in the morning, then weigh it again when you get back. The difference in weight should represent the amount of gas you burned for that day. I figure 3 scales should do it for a light bike, one under the front wheel, one under the back wheel, and one under the kick-stand.

So, as for accuracy, it depends on the scale. Assuming we are after at least 5% of actual, here's how it lines up.

-If the scale is accurate to the ounce, then weeks of 15 miles or more can be measured within 5% of actual.
-If the scale is accurate to the tenth of a pound, then weeks of 25 miles or more can be measured within 5% of actual.
-If the scale is accurate to quarter of a pound, then weeks of 65 miles or more can be measured within 5% of actual.
-If the scale is accurate to half of a pound, then weeks of 130 miles or more can be measured within 5% of actual.

Here's a scale accurate to half of a pound:
http://www.amazon.com/Taylor-7009-Electronic-Lithium-Scale/dp/B0006B5NGY/

You will need the density of gasoline, which comes out to 737.22 kg/m³ (http://en.wikipedia.org/wiki/Petrol) or 6.1523 lbs/gal

11011011

Hi Dan:

___Great idea but I think you need a few more decimal places ;)

___Was the weight shown with the bike muddy wet, soaking wet, dripping wet or all of the above?

___Good Luck

___Wayne

Great idea but I think you need a few more decimal places ;)
Please don't encourage him. :D

If you burn multiple tanks a week, as I do (300+ mpw), then can't you just measure your MPG per tank for a week and take an average? I have and I get about 53 MPG.

I don't think weighing the bike would work. If you have luggage on board or carry items with you that weight varies depending on what you have in the bags. I know I would not want to dismount and remount my luggage just to keep track of my fuel burned.

For me my tank to tank data works fine in a spreadsheet. This allows me to easily sort, pull out highs lows, and average. Maybe I am missing something in what your hoping to accomplish that averaging across tanks won't accomplish?

Guy

Great idea , But I will let you try it first and if you post a picture of your bike on bathrrom scales would be a nice touch too, untill then , I will keep giggling at the idea of having 3 bathroom scales in the drive way and weiging the bike every day in the moring before you set off, and when you come back , just to get your mpg ... hehehehe Bonus points if you do it on the bathrobe , in the morning drinking coffee before seting of on the ride .. hahahaha :)

Great idea , But I will let you try it first and if you post a picture of your bike on bathrrom scales would be a nice touch too, untill then , I will keep giggling at the idea of having 3 bathroom scales in the drive way and weiging the bike every day in the moring before you set off, and when you come back , just to get your mpg ... hehehehe Bonus points if you do it on the bathrobe , in the morning drinking coffee before seting of on the ride .. hahahaha :)LOL!

Yeah the neighbors are used to my shenanigans. In theory one scale and the proper amount of trigonometry should do it. After chatting with a buddy, we realized a finely calibrated dip-stick should get you pretty close if you park the bike in the exact same position every day.

11011011