Confused About Low Fuel Indicator

[Jfeuillet]

I drive a 2009 Triumph Bonneville T100 with a Cozy sidecar hack, purchased a few weeks ago, and I'm trying to figure out the distance I can safely drive before refueling.

The Owner's Handbook claims that the fuel tank contain 4.4 US gallons of fuel. From recent refueling I calculated that I drive about 42 miles per gallon. So, in theory, I should be able to drive about 185 miles on a tank of gas.

The handbook also claims that the low fuel indicator light illuminates when there is about 0.92 US gallon left in the tank. So the light should come on when there is about 39 miles of gas left in the tank.

But, for the past 4 fill ups, the light came on at around 105 miles. This last fill up was 2.80 US gallons for 118 miles on the odometer. Quick math says I should have about 67 miles left to drive.

The fuel light appears to be misguiding. Is it because of the hack or is the odometer wrong?

 

[Qship]

I'm sure the hack is creating a lot of extra drag on your bike, so owners manual guidelines are probably out the window.
If you plan on pushing the envelope, I would ensure you carry some extra gas.
Also, from what I have seen, low fuel indicators vary considerably from bike to bike.

 

[Village Idiot]

Always use your odometer..........it doesn't vary.
Jim

 

[shanered6]

with the sidecar your bike has probably had its gearing lowered slightly and as said the extra drag will all add up to a substantial fall in mpg .

 

[Rocky]

I agree about the extra drag hurting MPG.
The fuel light on one of my bikes comes on far too early so I ignore it.
You already have a baseline with the mileage at 118. Why not extend that a bit more and note how much fuel it took to fill and repeat as necessary until you reach a point of approaching too low.
From that point on, or an earlier point, use the odometer as your guide to start looking for fuel and ignore the light.
I arbitrarily use 200 kilometres on the odometer as my baseline and fill up soon after.
It's always too soon, but better to be safe than sorry