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Currently bikeless. Buying a GS310 in Spring 2021
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Discussion Starter · #1 ·
According to my instruments CONS1 is 103 mpg after a 180 mile run!
I had checked my previous run of 177 miles and CONS1 was 101 mpg.
I filled the tank both times in the same garage and the same pump using the same method.
When I calculate petrol in and miles covered I actually seem to have got 88 mpg and 84 mpg.
How does the bike work out the consumption or it it just wrong?
 

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there can be a huge variance if you measure petrol in over distance, the variance can be up to 20% (due to angle of bike, expansion volume and how you fill up the bike). However, if you keep the records and measure it over multiple fill ups (5+) that variance drops towards zero.
 

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Discussion Starter · #5 ·
there can be a huge variance if you measure petrol in over distance, the variance can be up to 20% (due to angle of bike, expansion volume and how you fill up the bike). However, if you keep the records and measure it over multiple fill ups (5+) that variance drops towards zero.
Ok Porth, I will try the 5+ fills. Today over a 146 mile trip, fairly close according to Google Maps, the bike claimed 108 mpg. When I calculate it is was 93.
Since the miles recorded look fairly accurate I think it is safe to assume the bike is measuring fuel used in some strange way.

Does anyone know how it actually calculates MPG? Does it maybe base a calculation on, to the nearest one , a mark you have on the fuel gauge?

I am looking at an error of 17% and two 14%'s so far. You could certainly never trust any fuel information given by the bike. I have noticed a few folks think when the bike says you have x miles available, you might still have 1 litre reserve. That's 10% So you might have x miles plus 10%. Be as well just riding until the bloody thing stops!

Not impressed!
 

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might this be a UK Gallon . or . a US Gallon ..?!
Maybe the programmer did not know they are not the same .?
Just a head-scratching thought..
 

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might this be a UK Gallon . or . a US Gallon ..?!
Maybe the programmer did not know they are not the same .?
Just a head-scratching thought..
That could explain such a large "error"

Maybe it's calculated in L/100km and then converted to MPG and rounded up or down. They might do the same thing for temperature, you can check this by seeing if the temperature goes from 68F straight to 70F (there's no 69F when converting from Celsius without decimal points)
 

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Discussion Starter · #8 ·
I worked out that is it converts US gallons to litres I would have got 110 mpg as opposed to the 93 I actually got. The bike said 108 mpg.
Maybe we are on to something.
I find it hard to believe that a bike which has been on the market for 4 years would have such an obvious error and not be spotted before.
Any communication I have had with BMW Motorrad on any thing has been a waste of time. I might try them again the problem being I don't think anyone will know.
I asked a simple question on whether the rear carrier had changed between 2017 and 2021 and no one at BMW could tell me. What chance do we have with this.
 

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Discussion Starter · #9 ·
Spoke to BMW Motorrad Edinburgh. You cannot change the units on the bike yourself. It requires a software upgrade. This should have been set when the bike was PDI'd by BMW. The dealer does not seem to be able to do this. Have written to BMW Customer Services but waiting 3 months for a warranty card from them!
 
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