No, just one question. I know how inaccurate the gas gauge is on ANY bike! I was speaking about the MPG computer (push joystick to the right twice....etc.) I have now started to calculate MPG the way I always have, dividing gallons by miles....oh wait a minute....maybe its miles divided by gallons. Whatever, it's the manual way. But to be even more accurate, given that its hard to put in fuel to the same level every time, I need to know what the odometer error is. Next time I'm on a highway with mile posts, I'll calculate that. I've found that most bikes are between 1 and 2% off which amounts to about a mile or two every 100. OK, I know, picking nits now! But it's the anal side that wants to know as accurately as possible.
The fact that your odometer/trip meter isn't
EXACTLY accurate shouldn't be a real issue, cos that inaccuracy won't vary much at all over time, so your '
measured miles travelled' will almost
always be directly comparable to any other '
measured miles travelled' that you've recorded from the same odo/trip meter.... unless maybe you've fitted new tires recently?? Cos
that will vary the 'miles measured', albeit usually only a tiny amount if you stick with the same brand/type/size of tires, but possibly as much as maybe a few percent if you've changed tire brands &/or sizes.... Still, since your Odometer/trip meter is pretty much
ALWAYS going to be
consistent in its inaccuracies, and it's
NEVER going to be
EXACTLY accurate anyway, you might as well just use the trip meter reading to record your '
distance travelled or measured miles travelled' & simply work off that - trying to get your '
measured miles travelled' any more accurate will rapidly see you spiralling down a rabbit hole chasing after an always elusive & never truly achievable exactitude!! :gaah: Altho if you are riding in an area with good satellite reception all the time & you have a proper GPS with multi-satellite reception capabilities that stays on all the time rather than a 'street directory' type GPS, then you could use the distance travelled between fuel stops that it records?! Maybe...
Regardless, in most cases, those 'dash computer generated' instantaneous MPG readings are even more inaccurate & pretty much always significantly more inconsistent than working out your average miles per gallon over 5 or more tanks of gas using however much fuel you've used over however many miles (even if you've manually calculated that mpg using 'known to be inaccurate distances due to speedo/odo inaccuracies' and the inaccuracies that are found between different gas pumps figures!) simply because the computer will be working off those same 'inaccurate' distance travelled figures anyway, PLUS they'll also be using the most recent instantaneous fuel use readings supplied by your injector system!! There is some 'averaging' of that which varies between make/models of vehicle &/or computer, but it's always weighted heavily towards the
most recent fuel flows based upon your
most recent driving, so if you back off on the throttle as you gently coast to a stop you'll usually see a better MPG reading than if you've just been working the engine & blasting thru the twisties high up in the rev range & you then just pull up & instantly shut down!! Of course, the better the software & the greater the computer control, the better that computer generated MPG reading can be, but it will
ALWAYS be biased towards your most recent riding, so it's not necessarily all that great an MPG reading to go by when working out something like a 'safe ryding range between fuel stops', cos it's nowhere near a 'long term average' and if you rely on achieving that sort of milage over a full tank under different riding conditions, you might well end up walking!! :lecturef_smilie:
Same thing applies to working out your fuel economy on just
ONE tank of gas & relying on that for your 'safe ryding range between fuel stops' - it might not be quite so 'instantaneously biased', but it's still going to be a figure worked out over your most recent riding - so if it looks really good cos you've just done a couple of hundred miles riding lightly loaded with the wind behind you on the open highway travelling at 50 mph, then relying on achieving that same MPG to work out your expected range while riding into the wind with a full load & your pillion passenger aboard as you blast thru some high speed twisties at or close to peak revs all the time is probably gonna see you walking well before you ever expected to run outta gas!! :gaah:
To give yourself a reliable & helpful 'average fuel economy' figure, you need to keep a record of how much gas goes in at every fill-up, how many miles you've travelled on that much gas, and you need to use at least a few tanks-full to arrive at a meaningful & useful average. Do that religiously and keep refining the average as you go, and your 'average fuel economy' figure will get better and better over time!
hyea: Sure, it'll vary up & down a little as your ryding style, conditions, & loads change for each ride, but the more tanks of gas & miles covered that you use, the 'more accurate' it gets - but be warned, it still might not cover you for those odd infrequent occasions when the roads/conditions are so much fun (or tough), your load is so high, or you ride so hard that your machine is working at it's absolute limits all the time; and on the other end of the scale, you might occasionally get absobloodylutely phenomenal range because everything worked together to make saaay, 500 miles on a tank of gas possible just this once! :shocked:
![IMG_1583[1].jpg](https://www.spyderlovers.com/data/attachments/98/98631-bc094f99b0de08b70c650d8f96139703.jpg?hash=g5uLQNcGJ0 "IMG_1583[1].jpg")
