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Discussion Starter · #1 ·
This is no big deal but just for infor, apologies if it has been mentioned before.

I was on my way back from doing some bike training today and stopped to fill the Thruxton up. When I was back on the road the fuel gauge went up to full after a a short delay as normal, but the miles to empty which was on about 40 miles before the fill up only went up to 90 miles.
Over the next hour it very slowly went up 1 mile at a time until it read 108 miles and then started reducing again. This I think was the point where the fuel matched the miles to empty correctly.

At first I thought it was because I had over filled the tank and that somehow sent the sensor a bit iffy. But thinking about it now although my ave mpg was showing 58 over the last few hundred miles, I had just spent an hour or so doing low speed machine control exercises so I guess my fuel economy was very low, and perhaps it was using this much shorter measurement range to calculate the miles to empty. That makes more sense doesn't it?

I think I am just a bit slow with the brain cells today.
 

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I have been setting only one of my trips to zero (on my T120), leaving the other with the mileage reading I just completed on the tank just emptied. This seems to be enough to get the miles until empty to reset. It seems that my range until empty is about 200 miles. I've been getting a pretty consistent 51 mpg, this is from a simple calc after filling up. I've not paid much attention to the display of mpg or avg speed or whatever.

I believe that the miles 'til empty is a current calculation based on very recent engine consumption, how recent, I have no idea.
 

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The calculation continually updates based on the way you are riding and your average fuel economy. As you ride the computer will change the miles to empty and it will eventually settle but it can change again if you start to ride more slowly or more aggressively.

It's normal for the bike to start with a conservative number and then update based on how you ride. Its also normal for the fuel gauge to take a few miles to show the tank as completely full. The MTE calculation will take this into account as well and change as the sensor finally detects a full tank.

I dont know why the fuel sensors are slow but I have other bikes that do the same thing.
 

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Discussion Starter · #5 ·
Thanks for the replays, interesting stuff.

I had no idea that the tripometer effected the miles to empty reading, I would like to understand why it would.

From what I saw yesterday I can see that the bike uses the recent average consumption to do its calculation, but it wasn't based on the miles done since I last reset the trip. I have never rest it and after filling up the tanks 5 or 6 times the miles to go has always gone up to between 170 and 180 miles. (My average mpg during this time has been 58 ((UK). However an hour of slow riding which covered less than 5 miles was enough to half the mikes to go after the next fill up, even though my mpg figure had hardly moved at all.

That suggests that the bike only uses very recent data to calculate miles to go IE just a few miles, but if that was the case then after a few miles of normal riding the miles to go should have quickly gone up to the normal 170ish figure. What it actually did was very slowly rise to just 108 over the next hour and 50 odd miles.
 

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You would think the tiny little engineer that they put in the instruments could give us some sort of explanation about how that "miles 'til empty" is calculated. I have seen mine rise while riding and then fall, it is hard to figure, wonder if Triumph could provide an explanation on how the calculation is done, is resetting it dependent on resetting one or both trips, etc.
Yes, my mpg above is on U.S. gallons.
 

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Thanks for the replays, interesting stuff.

I had no idea that the tripometer effected the miles to empty reading, I would like to understand why it would.

From what I saw yesterday I can see that the bike uses the recent average consumption to do its calculation, but it wasn't based on the miles done since I last reset the trip. I have never rest it and after filling up the tanks 5 or 6 times the miles to go has always gone up to between 170 and 180 miles. (My average mpg during this time has been 58 ((UK). However an hour of slow riding which covered less than 5 miles was enough to half the mikes to go after the next fill up, even though my mpg figure had hardly moved at all.

That suggests that the bike only uses very recent data to calculate miles to go IE just a few miles, but if that was the case then after a few miles of normal riding the miles to go should have quickly gone up to the normal 170ish figure. What it actually did was very slowly rise to just 108 over the next hour and 50 odd miles.
I think you're right on. I dont think the trip has anything to do with the calculation.
 

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Did some experimenting this morning - filled the tank up all the way, to just under the flat bottom of the filler neck. Neither trip meters were reset. During a ride of about 80 miles running in 3rd or 4th and between 40 and 55 mph with a number of stops thrown in, here is what I could observe:

1. The "miles 'til empty" (MTE) slowly climbed over the next 10 miles to about 170 or so.
2. Coasting down a 3/4 miles hill with the clutch pulled in and engine at idle speed (1K rpm), the MTE climbed by 7 miles. I repeated this on a shorter hill of 1/4 mile in length and the MTE climbed by 2 miles.
3. Over the course of the ride when I added the miles ridden with the MTE, it had, after about 25-30 miles climbed to a best total of 225. I only saw this briefly and the total seemed to settle in at about 205 to 210 miles.
4. I was riding very conservatively (sedately as Forchetto would say), which is how I usually ride, so I figured that I was getting the best mpg that I could ever get out of the bike at this point in its life.

My T120 only has about 1100 miles on it.

So, my conclusion would be that the computer calculation of MTE is based on the last few miles or fraction of miles that you have ridden and how they were ridden - i.e. if you were wringing the neck out of the engine, that is what will be reflected in the current reading of MTE and that resetting the trip meters has no impact at all on the MTE displayed.

I looked at those displays so much during this ride, that I doubt I'll do that again, that was a PITA!
 

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Discussion Starter · #9 ·
Thanks, I think I concur with your findings.

It is just possible that the Triumph Engineers added a clever bias, something like 70% of the MTE based on the last few miles and 30% on the last 100 miles, just to calm down the fluctuations when the riding style changes.
However accepting that the measurement is fairly short is close enough for me. I won't panick if I do a bit of motorway filtering and the MTE plummets.
 

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I have not taken delivery of my Thruxton 1200 R yet, so I can't speak for the accuracy of their 'range' display. However, with all my other bikes I've learned the only truly reliable indicator is the trip odo and a measure of experience calculating consumption and true capacity. I will write trip odo readings on fuel receipts for a few thousand miles and plug the figures into a spreadsheet. The observations are always enlightening, as they're likely to change as the engine is run-in, the Season and average temperatures (and the resulting fuel formulations), the nature of the trips (sport, touring, etc) and the altitudes encountered. I plug those in.

It doesn't take long before you begin to see patterns and you begin to have hard data reflecting how your bike consumes fuel, what is normal and what is not. A simple range calculation based on actual consumption gives you a good baseline to compare to the computer range display.

I should add that, since Euro speedos are normally within 10%+5mph, your trip odo is probably not spot-on. But, for the sake of these calculations the error is irrelevant since you're using indicated miles as thee baseline.
 

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Discussion Starter · #11 ·
Yes I always used the trip on other bikes to know when to fill up including a recent ST3.

However I don't think I will be using it on the Thruxton. In addition to the miles to empty reading it also has a fuel gauge and a 3 ltr remaining warning light so I think I am covered.

Also unlike the ST3 you can not view the important (to me) information all at once. I like to know the time when on the bike and at least while its new the ave mpg. To add in the trip as well would only increase the cycles needed through the 6 LCD screens.

A customisable LCD panel would be ideal. I would have a much larger gear indicator and a small clock and ave mpg all on one screen.
 

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OK I joined this thread because I've had some relevant experience but come on guys, spread sheets and long term testing? really? Is this why we ride these bikes? Sheesh, its not that important to me, Im here for some fun on the road not to geek out about gas mileage. :wink2:
 

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OK I joined this thread because I've had some relevant experience but come on guys, spread sheets and long term testing? really? Is this why we ride these bikes? Sheesh, its not that important to me, Im here for some fun on the road not to geek out about gas mileage. :wink2:
Sorry, I thought the whole point of riding was to fill spreadsheets, compile masses of tables and draw beautiful graphs. Isn't that fun for you? :nerd:
 

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I don't know for certain but it looks like the miles remaining (range) display on my T120 is miles to reserve, rather than miles to empty.

I like how the range display number gets smaller at rates that seem to vary with current consumption. The miles remaining number never increases, and it doesn't constantly bounce from a lower number to a higher one.
 

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I have not taken delivery of my Thruxton 1200 R yet, so I can't speak for the accuracy of their 'range' display. However, with all my other bikes I've learned the only truly reliable indicator is the trip odo and a measure of experience calculating consumption and true capacity.
Bootworks,

Up until last Saturday I would have absolutely agreed with you, but then I took delivery of my T120. My attitude changed, over a period of hours. Now, I'm determined to use the marvelous tech built into the bike, if I can only understand what it's trying to tell me!

Right now, I'm not sure whether the number to the right of the little arrow-with-fuel-pump icon is the calculated miles to empty, or to reserve. Either way, when the trip odometer reads 150, I'm gonna be looking for that gas pump.
 

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Discussion Starter · #17 ·
I don't know for certain but it looks like the miles remaining (range) display on my T120 is miles to reserve, rather than miles to empty.

I like how the range display number gets smaller at rates that seem to vary with current consumption. The miles remaining number never increases, and it doesn't constantly bounce from a lower number to a higher one.
I am sure it is the same as the Truxton in which case it seems like it is certainly miles to empty. My low fuel warning light (3 ltr left) comes on at about 40 miles to go.

The MTE will also go up if you change your riding style enough.
 

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The whole experience of having "miles to empty", plus the gauge, plus the low fuel light is quite an improvement over my other bikes. With those I remove the gas cap and shake the bike side to side while trying to gauge the sound of the slosh. That is, if I remember to check at all before running out.
Some things are a lot better in 2016!

Glen
 

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Sorry, I thought the whole point of riding was to fill spreadsheets, compile masses of tables and draw beautiful graphs. Isn't that fun for you? :nerd:
Hahaha Personally, I love to ride, and I love to fill out spreadsheets and see what the graphs look like.
 

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My experience today on my Thruxton R leads me to think the number to the right of the gas tank indicator is miles until empty. My gas light came on when I was at 103 miles into the tankful, the indicator showed two bars (of 8) on the display, and miles remaining showed about 49. That would mean the tank is about 150 miles til empty (which seems about right) and that the gas dummy light comes on stupidly early.
 
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