Average mpg reading

[vito1943]

Am I doing something wrong? When I fillup the tank, I zero out the miles ridden and mpg for both trip meters and the odometer mpg number. Sometimes the data on the next ride makes sense but sometimes it makes no sense. It will show the miles traveled, but the mpg average will read something like “2.3” or some other ridiculous number while the instant mpg always seems right. Am I missing a step or something else?

[FLJester]

My 2020 RT does the same thing but not with any consistency

[Peter Aawen]

Am I doing something wrong? When I fillup the tank, I zero out the miles ridden and mpg for both trip meters and the odometer mpg number. Sometimes the data on the next ride makes sense but sometimes it makes no sense. It will show the miles traveled, but the mpg average will read something like “2.3” or some other ridiculous number while the instant mpg always seems right. Am I missing a step or something else?

Yes you are!!

You're either believing or at least assuming that the info displayed is anything more than an occasionally somewhere near vaguely in the same hemisphere of the ball park figure representing the average info described, when really, it's little better than your worst WAG because the on-board computer 'calculates' that average from the notoriously unreliable & often downright incorrect fuel gauge reading, the more realistic 'miles travelled since last trip reset', and the latest average of all the instantaneous fuel injection volumetric data that's been collected since you did that last reset!! . And since the Instantaneous Fuel use figure will always reflect the big differences that occur in fuel use between things like just starting the engine, prolonged steady speed running, or saaay, coasting down a really long hill; then until the computer can gather sufficient data to provide a valid basis for the calculation, that'll mean 2 out of the 3 variables used will potentially be at best, wildly inaccurate, so of course the result displayed sometimes won't make much sense!!

You really can't consider ANYTHING that relies on info/data from the fuel sender to be truly accurate - the fuel tank shape & the vagaries of the data the sender produces means that is a fairly random variable that underpins so many things!! So don't RELY on the Average Fuel readings; the Miles to Empty; or even the Low Fuel Warning light et al!! . At any given time that info may not be at all accurate or even close to accurate!! . Sure, that sort of info is handy stuff to have, which is why BRP have made some (weak) attempt to provide it, and a quick glance at the info on your dash might be 'sorta helpful' occasionally, but seriously, if it's not data that you've read off the trip meter or calculated yourself from the amount of fuel you actually put in the tank, then it's suspect and as such is NOT RELIABLE!

Shame, but that's the way it is; and pretty much the way it's been since BRP sold their very first Spyder too!! So don't waste too much time trying to get it fixed - they may have improved these things a little since 2008, but it's not been a massive improvement, nor anything that's really made it safe to rely on, so don't hold your breath on it getting much better too soon!! Still, most of us with years of motorcycling behind us have managed quite well simply by using the trip meter/s, and maybe even doing a rough 'miles per gallon' calculation in our heads every now & then... heck, some of us even go the whole hog and keep accurate & extensive logs on all this stuff.... but the nett effect for us as Spyder/Ryker Ryders remains the same - use your trip meter info & the amount of fuel you just put into your gas tank as shown on the gas pump to work out your average milage & use that to work out how far you should be able to safely travel on a tank of gas; then set a trip meter at each refill to make sure you top up before you run down below about 1/4 of a tank (cos you don't want to destroy your injectors &/or pump, do you?!?) Then repeat as often as you feel comfortable with, cos each repeat will fine tune the accuracy of your calculated info & so it'll become more reliable over time! And none of the info displayed on your dash will do that!!

Then you just get out there to Ryde More, & Worry Less without relying on the often dodgy gas tank or usage derived info that might be displayed on your dash!

[RICZ]

vito1943....I assume you have a phone. I also assume that phone has a calculator. Why not keep things simple and easy and at gas fillups, simply do the arithmetic. Divide the gallons into the miles traveled since the last fillup. Then reset a trip meter. I use the A meter as it always shows the mile on the screen. Best part is, it's very accurate, whereas your dash readings are not.
As Peter sez....Ride more and worry less.

[vito1943]

I appreciate the comments, which basically are telling me that my Spyder is functioning the way others do, and not with some unique error in the onboard computer. For other vehicles I always used the gallons added divided into mileage on the trip meter to mentally calculate the mpg and I will do the same for the Spyder. If things stay consistently around the same mpg, I can multiply that by the gallons in a full tank and always know my conservatively figured amount before I should fill up again. As to the gas gauge, it seems less accurate than any recent 2 wheeler that I have owned, hardly moving at first and then dropping rapidly. As for now, I think 200 miles between fillups is a reasonable estimate to keep me out of trouble.

[RICZ]

As to the gas gauge, it seems less accurate than any recent 2 wheeler that I have owned, hardly moving at first and then dropping rapidly. As for now, I think 200 miles between fillups is a reasonable estimate to keep me out of trouble.

The rate of decent of a gas gauge is determined by the shape of the tank. Most motorcycle and Spyder tanks are larger at the top, kinda like an upside down pyramid. So the decent is faster at the bottom. Dig?

[2dogs]

200 miles on the odometer is a good spot to fill up. At 220/230 it starts getting a bit worrisome. There's a myriad of factors in play that can have beneficial and detrimental effects on your MPG that you could not be aware of. Anything from the gas pump where you last filled up to unforeseen road and weather conditions. And yes, even a faulty gas gauge. Running out of fuel in BF Egypt is not a fun or good experience. If anything it puts you and your passenger, if you have one, in danger. There are bad guys out there all the time just looking for an opportunity to take advantage of someone in a compromised condition, and score something for nothing.

[MrMagicFingers]

Hey all,

I use this android app. Though I have an older than current version, I love it!!

It allows you to track multiple vehicles and has custom input for each. Places for pictures and places for records and maintenance. You can make it as simple or as complicated as you like.

https://www.fuel.io/

Tim

[JayBros]

Vito, you're going to have to remember that, unlike a cage that has been designed to be pretty aerodynamic to meet Nanny government mileage regulations, with a Spyder you are pushing a barn door through the atmosphere. IME, once you and your Spyder are consistently rolling along at better than 3,200 rpm your mileage starts to go seriously south. If you're tootling around at 55-60 mph using a 200 mile refill point will ensure you always have some good reserve if gas stations start to become scarce. As your average speed increases, your refill mileage point will drop so that you maintain a decent reserve condition. Don't overthink the problem.

[vito1943]

Yesterday I went out for a three hour ride, and rode somewhat more aggressively than I usually do, just to see what mpg I would get. I ignored the Eco mode and generally shifted at about the 4000 to 4500 rpm point, and for much of the ride kept up 65+. I've been using 91 octane fuel and ended the day at 34 mpg. 34 times 7 gallons would mean I have a range of 238 miles so I think the 200 mile refill point is a safe and reasonable one to use. Obviously if I am stuck in city type riding, with slow speeds and stop and go movement, I would probably aim at a refill at no more than 150 miles.

[BLUEKNIGHT911]

Yesterday I went out for a three hour ride, and rode somewhat more aggressively than I usually do, just to see what mpg I would get. I ignored the Eco mode and generally shifted at about the 4000 to 4500 rpm point, and for much of the ride kept up 65+. I've been using 91 octane fuel and ended the day at 34 mpg. 34 times 7 gallons would mean I have a range of 238 miles so I think the 200 mile refill point is a safe and reasonable one to use. Obviously if I am stuck in city type riding, with slow speeds and stop and go movement, I would probably aim at a refill at no more than 150 miles.

Well that ... 7 gal. tank .... actually only holds about 6.3 gals...... Mike

[rjinaz86323]

Well that ... 7 gal. tank .... actually only holds about 6.3 gals...... Mike

interesting comment as I have put more than that in my 28 F3L on more than one occasion! I currently have right at 5400 miles on it, with a around 25% is freeway miles @ 80mph, and since I am getting 34.4 LTD based on actual fill ups.
Incidentally some of those miles were with 87 octane, based on availability.

[Woodaddict]

Obviously if I am stuck in city type riding, with slow speeds and stop and go movement, I would probably aim at a refill at no more than 150 miles.

well that info is a bit wrong. if you ride at slower speeds, even with some stop and go,,, you can refill at the 200 miles OR longer. the engine doesn't suck the gas fast at lower RPM's. only uses it faster at 70 mph or so. its like riding in mountains, slower speeds, up hill some, down hill some,,,,,,i have gotten 250 miles before a fill up

[motoguzziman]

My 2020 RT does the same thing. I find that the "Mileage to End" works pretty good for me. When it says I have about 48 miles to go on the tank, I put in about 5-5.2 gallons which still leaves about a gallon and a half in the tank before it would be empty. I just put on almost 2000 miles riding the hills in Arkansas and I was always using the distance to empty. Never failed me but the average mileage worked only about half the time

[vito1943]

Well that ... 7 gal. tank .... actually only holds about 6.3 gals...... Mike

It's actually 7.13 gallons according to the owners manual.

[Peter Aawen]

Well that ... 7 gal. tank .... actually only holds about 6.3 gals...... Mike

It's actually 7.13 gallons according to the owners manual.

Yeah, the 7 odd gallons (US) is actually the total volume of the tank, including any expansion space &/or nooks & crannies above the fill line/filler cap that you can't ever actually fill without spilling gas all over the place &/or pumping it in under high enough pressure to make its sides bulge.... Not that there won't be some gas stations with pumps so dodgy that they'll tell you that you just pumped more than that in tho!!

And then you also hafta consider the fact that the fuel pump sits inside the tank and uses the last 1/4 or so of the tank's usable capacity as both coolant & lubricant; which means that if you EVER run the tank dry/until the engine stops, chances are gonna be pretty high that by doing so you will've at least started some irreversible & cumulative damage that'll will gradually degrade your machine's performance and eventually cause the pump &/or the injection system to fail completely!!

So if you own a 2014 on RT & regularly ryde until you end up having to add any more than 6 gallons to fill it up, you'll probably be harming your Spyder's fuel pump &/or injection system and degrading it's performance a little bit more every time you do so, if not every time you ryde cos the cumulative damage has already been started!!

[BLUEKNIGHT911]

It's actually 7.13 gallons according to the owners manual.

Well in my experience ( 12 years of Spyder ownership ) NONE of the manuals tell you about the large air POCKET built into EVERY gas tank they make. However they include that air POCKET when they state the size of the tank ...... Mike

[2dogs]

Well in my experience ( 12 years of Spyder ownership ) NONE of the manuals tell you about the large air POCKET built into EVERY gas tank they make. However they include that air POCKET when they state the size of the tank ...... Mike

You know anyone who has found a way to easily overcome that air pocket limitation on fuel capacity? I've messed around several times trying to cram in more fuel and I succeeded in cramming 1 & 1/2 more gallons on several occasions. It takes a lot of patience but it can be done. One and a half gallons is a bunch of miles if you're on a trip. I've suffered no ill side effects after topping off the tank with that much fuel.

[BLUEKNIGHT911]

You know anyone who has found a way to easily overcome that air pocket limitation on fuel capacity? I've messed around several times trying to cram in more fuel and I succeeded in cramming 1 & 1/2 more gallons on several occasions. It takes a lot of patience but it can be done. One and a half gallons is a bunch of miles if you're on a trip. I've suffered no ill side effects after topping off the tank with that much fuel.

Let me try to give an example .... get a quart milk container ..... make a hole in the side about 7/8 ths. of the way up. pour water into the container until the water comes out of the Hole ..... even tho the container is not completely FULL ( and it never will be ) .... this is because of the Hole .... Spyder Gas tanks are the same way ....the filler ring is BELOW the top of the tank .... so it CAN'T get anymore filled than that .....jmho ..... Mike

[Peter Aawen]

The air pocket is built in as an essential 'fuel expansion space' on every automotive gas tank made since about 1974 (well, it was 1974 in Oz anyway! ) While it's often difficult to fill the tank right up to the filler cap level anyway, which is most often a feature of the pump/nozzles used tho, and not really a tank issue as such... the air pocket/expansion space is generally above the level of the filler cap, so you can't really fill it unless you turn your tank upside down anyway, only that empties out the gas in the rest of the tank! .

Since they went to sealed tanks without an overflow onto the ground back in 1974 or thereabouts, it's been essential to have that space available in any gas tank for the gas to expand into as it warms up to ambient air temps &/or hot car/bike tank temps, cos most gas is stored in the ground where it's kept nice & cool - and it's volume in the ground is somewhat less than it would be at ambient air temps!! So when you pump the gas outta the ground & put it into your tank, it immediately starts to expand in volume as it warms up! But then when you finish filling the tank, you put a 'non-venting' cap on the filler neck, and since the gas tank no longer has an 'overflow onto the ground' pipe, that leaves nowhere for the now expanding gas volume can expand into.... except the gas tank has a built in air pocket designed for just that purpose!! So that air pocket/expansion space is completely unusable for liquid fuel, but it's ESSENTIAL to avoid blowing up &/or rupturing the gas tank, with the potential explosive situations that could cause.... . But some vehicle manufacturers still include that extra volume in the tank as part of the listed gas tank capacity, despite it being effectively impossible to fill that bit above the filler cap up!!

All of which adds up to the fact that you REALLY SHOULDN'T EVER TRY TO CRAM MORE GAS IN once you've reached the lip of the filler cap - sure, that'll mean you probably don't ever put in as much gas as the manufacturer states is your vehicle's fuel tank capacity, but they knowingly included capacity that YOU SHOULD NEVER BE ABLE TO USE ANYWAY so even if you're a gallon down on that listed capacity once the gas reaches the filler cap lip, that's IT, FULL, FINISHED, DONE, CHOKKA'S, NO MORE!! You can't really put any more in anyway, even if it says you have a 7.3 gallon tank & you've only put in 6.8 gallons, cos it'll just run outta the filler, over your machine &/or leg, and onto the ground!!

Besides, it's actually EXPLOSIVELY DANGEROUS to over-fill your gas tank at the best of times, and even if you are only squeezing in the extra to bring it right up to the filler cap lip instead of about 1/4 inch below that, you are probably over-filling enough to either pop the tank or at least end up forcing neat gas (instead of fumes) into your Evaporation Cannister, if it's still fitted - which is not a good idea in any case... And besides, if you're trying to cram in as much gas as is listed in the specs as the tank capacity, then you must've completely emptied the tank to do that, and if you did that while ryding/engine running, then you've probably already irreversibly damaged your fuel pump; maybe juuust a microscopically tiny bit initially, but it's damage that will gradually get worse over time until it eventually causes an expensive failure, and THAT TOO, is not a good idea!!

Sorry about the metric references, but IIRC, the 2013 & prior RT's have a listed gas tank capacity of 22 litres but a usable capacity of only about 20 litres; while the 2014's & on have a listed capacity of 26 litres but only a usable capacity of about 23 litres, so if you're filling any more than that.... . And you REALLY shouldn't be running your tank down that low anyway, cos if you do run the tank on any modern injected engine below it's minimum required level (usually about 1/5th of a tank full) it WILL be causing that microscopic and irreversible damage to your injection system/fuel pump that progressively gets worse... initially maybe only a tiny loss of power & fuel economy that you don't necessarily even notice; but over time, that'll gradually build and get worse, and unless resolved by replacing the effected parts, eventually it'll result in a catastrophic (& expensive) failure!! Been there, done that, hopefully some can learn from my hard learned experience!

[BLUEKNIGHT911]

You know anyone who has found a way to easily overcome that air pocket limitation on fuel capacity? I've messed around several times trying to cram in more fuel and I succeeded in cramming 1 & 1/2 more gallons on several occasions. It takes a lot of patience but it can be done. One and a half gallons is a bunch of miles if you're on a trip. I've suffered no ill side effects after topping off the tank with that much fuel.

I posted this elswhere : .... I fill until it AUTO stops .... then I slowly add 1.3 or .4 gallons more till it at the LIP ..... I do this consistently EVERY time I get gas ..... Mike

[rjinaz86323]

I posted this elswhere : .... I fill until it AUTO stops .... then I slowly add 1.3 or .4 gallons more till it at the LIP ..... I do this consistently EVERY time I get gas ..... Mike

I do the same. I have gotten as much as 6.6 gal in when it was just about dry. After being reminded about the fuel cooling the fuel pump (this was a trait of HD also) I will not run it that low in the future. Thx for the reminder.

[2dogs]

Unless I'm wrong the gas cap is below the top of the tank like BK says. Exactly just how much space is left in there I have no idea. My tank is not full until I can touch the gas with my finger, then I'm full. Someday when I have the time I'll siphon out all the gas in my tank and fill it up until it hits the bottom of the fill tube. Then I'll put in another gallon and a half and just see how much it will actually hold without running over in the ground. I've watched a gallon of gas expand sitting in the direct sunlight. It doesn't expand that much. I think that's why a military jerry can is shaped the way it is. You can never totally fill it up unless you tip to the side.

[2dogs]

I posted this elswhere : .... I fill until it AUTO stops .... then I slowly add 1.3 or .4 gallons more till it at the LIP ..... I do this consistently EVERY time I get gas ..... Mike

Exactly!

[Peter Aawen]

Unless I'm wrong the gas cap is below the top of the tank like BK says. Exactly just how much space is left in there I have no idea. My tank is not full until I can touch the gas with my finger, then I'm full. Someday when I have the time I'll siphon out all the gas in my tank and fill it up until it hits the bottom of the fill tube. Then I'll put in another gallon and a half and just see how much it will actually hold without running over in the ground. I've watched a gallon of gas expand sitting in the direct sunlight. It doesn't expand that much. I think that's why a military jerry can is shaped the way it is. You can never totally fill it up unless you tip to the side.

You might be surprised at how much gas can expand when heated - and remember that even sitting in direct sunlight might not raise the gas contained up to the temps the contents of your gas tank might reach when your engine is running, especially when it's all contained under an RT's tupperware; and then there's the fumes given off & the gas pressure that can create/add to the mix too!! . There's a good reason the 2013 RT's had that major heat recall done; just like there's a reason that the 'expansion space' in the 2014 & on gas tanks is proportionally a little larger than it is in the smaller tanks!