Interesting and very surprising things about the record MPG my trike delivered today

A few weeks ago, I picked up my brand new 2023 RG3 from my HD dealer. Yesterday, I finally had the time needed to examine the 306 page user manual for the BOOM! system. I read enough to at least get the “basics” of the “Trip Statistics” screen in the “Info” section of the software, so I was able to initiate a “trip” that was actually a 50k = 31 mile fuel milage test under what I would call pretty ideal conditions. I rode OUT 27 km and then rode back 23 km, on the same highway.

That test ride resulted in a new MPG record for my specific trike: 4.3 Liter / 100 km which equates to 54.7 miles / US Gallon!

Here are 2 photos of the “trip statistics” screen, one taken just after 27 km (just over halfway mark of the test, at the first safe place to pull off the highway), and the other taken at the end of the test at 50km:

Halfway photo at 27 km:




Test completed photo at 50 km:





The test ride started with a just-filled fuel tank. Note the fuel gauge reading at the end of the ride in the 2nd photo.

Note that the ambient conditions were as favourable as I could have them for this attempt at a record run:

• The ambient temperature was cool: 11degrees C (at start) to 12 degrees C (at finish) which is 53.6 to 55.4 degrees F. This was the first time I did a MPG test ride in weather this cool.
• The wind was “moderate for our area (2nd windiest region in Canada), gusting bewteen 11and 23kph, and it was a perfect “crosswind”, right across the highway at about 90 degrees. So, it affected MPG in a small way (even a CROSS wind affects MPG), but avoided being either a headwind or a tailwind (evidenced by the fact that MPG in both directions was identical).
• The road is a divided 4-lane highway, in gentle rolling prairie, mostly straight with very gentle “interstate type” curves.
• I used cruise control in both directions.
• I used the cruise control to hold the speed at 80.6 KPH = 50 MPH on the cruise control. (The photos show a lower AVERAGE kph only because the onboard computer use total ACTUAL time, including getting out of my residential area to the highway, and a few minutes I spent on the side of the street in the residential area figuring out how to get to the “GO” button after finally getting the “Round Trip” accepted by the system).
• I KNOW that the odometer on my RG3, and the Trip Statistics screen, are both correct, as on my recent to and from trips to my HD dealer 173 km away, my odometer gave EXACTLY the same distance ridden for the trip as Google Maps predicted.
• And i know that the MPG calculations that the trip statistics screen makes are also correct from that same trip to and from the dealership, where the screen display showed almost exactly the same number of liters of gas consumed as the local gas station pump subsequently showed after the tank refill.
• Also, look at the fuel gauge in the 2nd photo. It shows less than 1/8 of a tank of fuel consumed. So, while an HD fuel gauge might not be “linear” with actual fuel usage, it is not wildly off like HD fuel gauges of “yesteryear” apparently were.

There were some interesting, and some very surprising, things learned via this test run:

• Despite the fact that most trike riders seem to get about 41 MPG (or worse) under typical (not twisty road playing) cruising conditions, today’s run proved that a trike CAN get at least as good as 54.7 MPG if you are riding solo under good ambient conditions, and absolutely need really good mileage because your are low on fuel and don’t know exactly how far to the next open gas station
• Kevin at our forum sponsor DK Custom looks to be correct when he says our HD engines run more efficiently when cool versus hot.
• My oil temperature at the end of the run was only 192 degrees F, which is considerably cooler than most trike riders who have the means to measure oil temperature are reporting. Again, I attribute this to the lower ambient temperature during my ride.
• The 54.7 MPG achieved today almost exactly matches the best MPG record rides I had my on my prior Harley, a 2023 Breakout 117. The RG3 did this despite having at LEAST 50% more frontal area than the Breakout, weighing 477 lb more, and having supposedly higher drivetrain power losses due to the 3 wheel configuration and rear differential. I have to assume this is because the Road Glide fairing on the RG3 has tHAT much impact versus the un-faired Breakout 117. I DID have a micro windshield on the Breakout for those record MPG runs on it, BUT that micro windshield was under 1 square foot in size, so was no match for the smooth curves and larger size of the Road Glide fairing.
• Note that my 2023 RG3 114 has a Stage 1 tune via Rinehart slip-on mufflers, HD Heavy Breather ‘Extreme” air cleaner (HUGE), an HD Stage 1 tune, and a Smart Tune to optimize the tune to my specific trike. It also has a DK Custom 1" tank lift on it now. This proves another truth that Kevin at DK Custom has been trying to tell us: a PROPERLY “tuned’ engine does NOT have to deliver worse fuel mileage than a stock engine, if the tuning was done with the RIGHT parts and the RIGHT tuning technique. And this appears to be true even if the tune applied is a genuine HD tune that is constrained by EPA rules and limitations. Kevin’s own trike, which was tuned by a non-HD tuner, even makes more than 100 rwhp, which is a big leap over the stock 90 rwhp of the 114 engine. And his MPG, under typical riding conditions, is NOT worse than the MPG of untuned stock trike engines.

Lots of food for thought.

Jim G

 

Jim,
Id like to see your temp test at higher speeds!

My legal HWY speeds are 70 MPH and 75 MPH. One can also run 5 to 9 miles over that and not be stopped in my state.

I know your up there in Canada, but maybe a trip to Montana sometime?

Ride safe, Mike

 

I know we don't regard the HD "Range" generated by the trike's computer as necessarily accurate, but I did a rough calculation:

After the MPG test, that tank of fuel fed the1.6 km trip from gas station to home, and then the 50 km MPG test, so a total of 51.6 km since fill-up.

The "Range" predicted by the onboard computer is now at 451 km.

So, according to the RG3 computer, this tank is good in total for 51.6 + 451 km = 502.6 km/

But the tnak holds 22.7 liters.

So, the computer is estimating 22.7 / 502.6 = 4.5 Liters / 100km which is 52.3 miles / US gallon. That is actually not too far off the 54.7 that the trip statistics screen shows. Only about 4.4% off, which is not bad compared to what some owners have feared.

Jim G

 

My F-250 get 70 Mpg when coasting down mountain passes... It doesn't matter how good you can make MPG on a short trip... It only matters what you normally get with normal riding at typical speeds, averaged over a few tanks.

I get 40-45 mpg on my LRST depending on city or highway. Normal driving... Meaning lots of throttle. That's been consistent for a while. When we go on trips, the wife's 2020 tri glide gets the same range as me. She has 6 gal, I only have 5. On a recent trip we got stuck in traffic going up a pass. We knew gas was at the bottom on the other side. We were sweating it. We made it. Mine said I had 20 miles, hers said 15. We both had around half a gallon in the tank. She doesn't get better gas milage than me.

If I'm sweating fuel, I stop engine braking, and I stop doing 80 mph. That's as good as it's going to get. I know how far I can go, I know where next stop is.

If you want to verify distance or speed, you have to track GPS.

 

And I keep wishing that my '18 Tri-Glide had either a 7-spd. trans (or an overdrive) that would allow me to cruise at 80 MPH @ 3,000 RPM's.

I replaced the 5-spd. trans in my '00 with a 6-spd to lower my RPM's at cruising speeds but then I just drove much faster and used the same amount of gas!