The Missing Gallon (Triumph Trophy SE)

Ever wonder how big the gas tank really is on a Triumph Trophy SE? I know I have. The manufacturer lists the Fuel capacity at 25 L (6.6 US gal). I've never come close to putting that much gas in the tank.

Since I do a lot of long distance riding fuel management is very important. I have an auxiliary fuel tank to extend my range and only buy gas when I need to. My theoretical capacity is just under the
Iron Butt Rally™ maximum of 11.5 gallons. My aux tank is 4.8 gallons so coupled with the stock tank I should have 11.4 gallons. I've never managed to put more than 10.5 gallons in it and I was worried about running out of fuel at those times.

Here is some background discussion about the Trophy's instrumentation. The on board computer shows some interesting information. You can display lots of information but the ones I want to focus on are distance to empty (DTE) and gallons consumed (GC). I've been displaying GC for the last 40,000 miles and have found it very useful and accurate enough that I trust it. Rarely has the displayed GC varied by more that 10% of what the fuel pump said I had put in. This error could possibly be explained by temperature variations in the fuel.

The low fuel light comes on at 1/4 tank at which time the DTE moves to the forefront of the display. The low fuel light and the DTE have no correlation. Depending on what kind of gas mileage you are getting the DTE can be anywhere from 40 to 80 miles when the low fuel light comes on. The DTE will count down and reaches zero (0) exactly as the last fuel indicator bar goes dark. 

After 60,000 miles I decided to conduct an experiment. I have developed enough confidence in the GC display to trust that it was accurate enough to test my tank capacity. I was returning from a 7000 mile journey and was trying to stretch my range so I could get home without a final fuel stop.

My low fuel light came on and the GC reported that 4.4 gallons were consumed. I watched the DTE count down to zero and logged the odometer and the GC. GC now reported that 5.4 gallons had been burnt. I motored on and ran out of gas 40 miles later! GC now said I had burnt 6.2 gallons. I had FINALLY found that missing gallon.

 

Well, it's nice to know there is a reserve but I can only see using it in an extreme situation. When your gas gauge says empty, the DTE says ZERO, and the low fuel light is screaming at you it's difficult to have faith and believe that there is more gas in the tank. [There's a song about have faith and believe "Desert Pete"]

It's a shame that Triumph couldn't have been more accurate with their instrumentation. I'd sure like to see it like my BMW K1200LT. The low fuel light came on when the DTE was at 40 miles based on current fuel economy. It was NOT tied to the fuel gauge. Once it went below 10 miles it turned to dashes. Not ideal but better than the Trophy. I have to stare at a bright yellow low fuel light for up to 100 miles which can translate to 1 1/2 to 3 hours.