11-05-2017, 03:24 PM
(11-05-2017, 02:38 PM)Cormanus_imp Wrote: Good rule, Flyn.
A bit like you, I've always operated on the premise that I could probably wring about 250 kms (155 miles) out of a tank, and I've tended to want to fill up around 230 kms. The beauty of Noroomtomove's First Law of Motion and Fuel Consumption is that I'm now pretty comfortable that touring I can get a more than that without becoming too anxious.
On a recent trip my reserve light has usually started flashing at around 210 kms (130 miles). Applying NRTM's Law tells me I have another 84 kms (52 miles) up my sleeve which is an extra 44 kms (27 miles) over my normal expectation—294 kms total rather than 250 kms. However, if the thing starts flashing at 165 kms (102 miles), I've got only 66 kms (41 miles) and I need to be much more concerned about filling up. Plenty of city riding dramatically reduces my fuel economy.
That's also what i like about Noroomtomove's method. It takes into account the current fuel burn. One of the things that worried me about my second fuel scare was that I'd been riding at 80 mph into a 20 mph headwind. The gauge started flashing early because I was getting less than 40 miles/gallon rather than my usual 50.
I use a similar method in my airplane. By running one of my two tanks until it's empty, I can calculate the exact fuel burn on that particular flight and accurately estimate how far I can go with my remaining fuel. (fuel burn rate varies with altitude, power setting and winds)
Thanks for the this extremely practical and usable post!
