Question about the indicated range to empty

[88bmwjeff]

I have a question regarding the miles to empty on my 2018 R1200 GS. The manual says there's 5.3 usable gallons of gas and 1.1 gallons of reserve. After filling up, the range to empty is about 165 miles, which would equate to an MPG of ±31 if based on the 5.3 usable gallons. If you exclude the 1.1 gallons of reserve, there's 4.2 gallons of gas, and if this amount is used the MPG would be around 39. The bike indicates I'm getting around 42-43 MPG, and the range to empty would be ±225 miles if based on the 5.3 usable gallons. Oddly, the miles to empty plus the trip meter (which is the miles since I've gassed up) slowly increases to over 200 as I get down to about a 1/4 tank.

My question is this. How is the bike estimating the range to empty? I've looked through the Rider's Manual, but this is not explained. It would make some sense to have the range excluding the reserve as an extra precaution to avoid running out of gas, but I wish BMW would be up front about it.

 

[MarkL]

Base on previous tank of gas.

 

[88bmwjeff]

Base on previous tank of gas.

Based on it how?

 

[ccolwell]

The only way to figure this out is to carry a bottle of fuel with you and run it to empty. After a couple of anxious rides on my SD GT I got a 1l MSR bottle and did just that.

 

[lee]

Range to empty is based on your MPG average since you filled. It will change after you ride awhile. I don't pay attention to the range immediately after I fill (the figure you see after a refill is probably based on the last tank).
During your ride the range will change as your riding conditions, speed and wind changes.
Our cars are the same way.

 

[Omega Man]

I’m not really trusting of such devices. I have watched, a few times, for when the low fuel indicator came on and made a mental note of the trip meter mileage. When the trip meter hits that mileage, time for fuel.
OM

 

[vtbob]

Range to empty is based on your MPG average since you filled. It will change after you ride awhile. I don't pay attention to the range immediately after I fill (the figure you see after a refill is probably based on the last tank).
During your ride the range will change as your riding conditions, speed and wind changes.
Our cars are the same way.

+1 It is an adaptive algorithm based on the most current fuel usage rate.

 

[lkraus]

In my experience the range is calculated by multiplying the average consumption rate since the average was last reset by the fuel level, not including the "reserve". So I reset the average at every fill up, and know that I can travel at least another 35-45 miles after the estimated range shows "---".

The range increases for a time after a fill up, partly because the gauge takes while to register the new fuel level, partly because it starts at zero mpg after a reset (remember what a zero does to an average), and partly because consumption is high for the first few miles as I leave the station and get back on the road. I don't consider the range valid until it starts to drop, which can take a surprisingly long time.

 

[lee]

In my experience the range is calculated by multiplying the average consumption rate since the average was last reset by the fuel level, not including the "reserve". So I reset the average at every fill up, and know that I can travel at least another 35-45 miles after the estimated range shows "---".

The range increases for a time after a fill up, partly because the gauge takes while to register the new fuel level, partly because it starts at zero mpg after a reset (remember what a zero does to an average), and partly because consumption is high for the first few miles as I leave the station and get back on the road. I don't consider the range valid until it starts to drop, which can take a surprisingly long time.

It can still change even when you're down to the last gallon.

 

[akbeemer]

A careful reading of this thread convinces me that I should continue to ignore the estimated range function on all my bikes as I have done in the past.

 

[lee]

A careful reading of this thread convinces me that I should continue to ignore the estimated range function on all my bikes as I have done in the past.

Keep an eye on the gas gauge. The only thing worse than pushing a bike is pushing two bikes.

 

[pglaves]

Two cases of anecdotal evidence: On our G310GS bikes the system (computer) tracks fuel usage in real time. There is actually a display that can be selected that shows this. I never use it. But one typical ride for us is through and about Big Bend National Park. We fill up at Study Butte just outside the park. Then we ride around in the park where the speed limit is 45 and we only cheat a little sometimes. Federal tickets are expensive. The "range" display shows fairly large numbers. When we leave the park and ride home on the 75mph highway range drops precipitously.

Now sometimes the opposite happens. I occasionally fill the bikes from a gas-can at home. Then we ride to the park. The range might be shown as 160 or so when we reach the park. But then shortly after entering the park the range will steadily increase to 200 or more as we ride more slowly in the park.

Both bikes have been ridden until the range shown was a single digit; mine down to zero at least once.

This contrasts with my 2014 Ford Focus. If it says range is 100, count on 50. Early after a fill it seems reasonable but those last two or three gallons disappear very fast.

 

[r0ckrat]

A careful reading of this thread convinces me that I should continue to ignore the estimated range function on all my bikes as I have done in the past.

Or use it as a rough estimate +/- 20 miles, and knowing that there is sill a reserve.

 

[strataj]

Or use it as a rough estimate +/- 20 miles, and knowing that there is sill a reserve.

I don't think this is correct. When the low fuel indicator comes on, range is then displayed (IE replacing temp, PSI).

I'll use range when I think I'm riding in areas with questionable available fuel, it helps motivates me to find some

 

[cabnfvr]

To determine mpg just fill up and observe how full the tank is, then ride until the reserve comes on (or before, doesn't really matter). Divide miles ridden by gallons purchased to fill back to the same full point observed earlier.

Knowing your average mileage is useful but this and the odometer method are not 100% reliable since speed, head wind, terrain all affect mileage. Learn your bike and trust what it's telling you. (But DO NOT run it this empty. The fuel pump is cooled by the gas in the tank.)

 

[t6pilot]

I do not trust my fuel guage
Every fill up I reset my trip meter at 200 miles I start getting anxious have gone to 260 a couple times. Sweating bullets by that time. With low fuel lite on never taken more than 5.5 gallons. 15RT with 6.6 tank I

 

[brownie0486]

I reset the trip, know I can run 160-170 before looking for fuel and I'll have enough left in the tank when I do fill up [ not on fumes ]. The computer has said 15 miles left and there was .8 gallons in the tank.

Doesn't matter what the computer tells me is left, I look for gas at 160-170 miles on the trip meter.

 

[akbeemer]

The secret is to ride with a partner who has a significantly smaller fuel tank than yours. Hence, Annie on a R1200GS and I was on a R1200GSA. I recently switched to a R1250GSA, but it will have a sidecar on it. I will probably get 30 MPG, but I’ll still have more range than Annie. The chances of Annie running out of gas are similar to my chances of medaling in gymnastics at the next Olympic Games.

 

[pglaves]

The secret is to ride with a partner who has a significantly smaller fuel tank than yours. Hence, Annie on a R1200GS and I was on a R1200GSA. I recently switched to a R1250GSA, but it will have a sidecar on it. I will probably get 30 MPG, but I’ll still have more range than Annie. The chances of Annie running out of gas are similar to my chances of medaling in gymnastics at the next Olympic Games.

In our case the opposite is true. Voni gets better mileage than I do. So I am safe from her wrath at least. Even if I run out she won't. There was one time, at Marble. CO when I needed to siphon fuel from her bike to mine. She scowled a little but we both laughed later. Jim Shaw who was riding with us was quite amused.

 

[bigjohnsd]

My '14 GSA would always say I was out of gas as in ) range but it never took the full measure to fill the tank, always had at least 1/2 a gallon.

My '21 GSA seems to be "top-heavy" the first half of the tank takes forever, the second goes fast. But I've only put 600 miles on since I got it in mid-January, I don't trust or believe the computer determined "Range" yet, I fill at 300 miles or sooner.