[ssncob]

There was a question earlier regarding trike mileage vs 2-wheeler. For me (18dct) pulling a loaded tailwind, over the course of 5200 miles of Rockies Gold and other driving I averaged 35.7 mpg. When doing the interstate with a mean headwind I was getting ~31.3 mpg. When toodling around at 50-55 mph I'd get 38-42 mpg.

When @Wheelss and I were heading back from Boomer's memorial we filled up and then hit the interstate for a bit. Now bear in mind his trike with the wheelchair has the aerodynamics of a set of car keys attached to a barn door. When we got off the interstate his miles to empty was 85 and mine was 145. Once on the back roads our mileage results were closer but still ~20% different.

If I'm riding conservatively without the trailer I get 46-51 mpg.

 

[Zee Fifty]

You can get some trikes with accessory fuel tanks so that a big bonus for those trikes…. That more than makes up for the efficiency difference….Assuming you can afford gas.

 

[ksiesel]

Altitude does a couple things to improve fuel efficiency.
The less density of the air means it's slightly less work to push the vehicle through. Golf balls, baseballs, etc fly further through the "thinner" air as an example. Airplanes fly further\faster at high altitude also for the same obvious reason.
Engines that are naturally aspirated (non boosted with pressurized induction) will run leaner since the thinner air carries less oxygen (short story version) and depending on engine mapping designs and available sensors may be able to run more ignition advance since detonation knock may be less apt to occur. Available power may be reduced but probably not very noticable unless underpowered to begin with or heavily loaded.
Your results can and will vary depending on your riding\driving habits.

Good write up on altitude effects. I'd like to add one to the list that you left out.

Pumping losses across the throttle plate are lower at higher altitudes. As the ambient pressure reduces (higher elevation), to create the same output power, the engine must open the throttle plate further to achieve the same absolute pressure between the throttle plate and the intake valve. This is the same basic concept that is used in variable displacement automotive engines. When they shut off cylinders (say run in V4 vs V8), one of the largest savings is it reduces the total volume of air they need to pull across the throttle plate (restriction) so it allows the throttle plate to open further to maintain the same power. When the throttle is open further, the pumping loss due to this air restriction is reduced.

 

[Zee Fifty]

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[jettawreck]

Good write up on altitude effects. I'd like to add one to the list that you left out.

Pumping losses across the throttle plate are lower at higher altitudes. As the ambient pressure reduces (higher elevation), to create the same output power, the engine must open the throttle plate further to achieve the same absolute pressure between the throttle plate and the intake valve. This is the same basic concept that is used in variable displacement automotive engines. When they shut off cylinders (say run in V4 vs V8), one of the largest savings is it reduces the total volume of air they need to pull across the throttle plate (restriction) so it allows the throttle plate to open further to maintain the same power. When the throttle is open further, the pumping loss due to this air restriction is reduced.

I left out a lot of minor stuff, probably a lot that I don't even know about. 😁
Another (small) reason diesel is more efficient as there is no throttle plate to make any restrictions and are adapted to turbocharging so well. Power is controlled mainly by fueling not controlling air intake volume.

 

[ksiesel]

I left out a lot of minor stuff, probably a lot that I don't even know about. 😁
Another (small) reason diesel is more efficient as there is no throttle plate to make any restrictions and are adapted to turbocharging so well. Power is controlled mainly by fueling not controlling air intake volume.

Agreed on diesels and well aware as I’ve spent the entirity of my career (so far) working as an engineer for the world’s largest independent engine manufacturer. Not to dive too far into the weeds, but the latest generations of diesels have also started to use exhaust and even intake throttle valves to increase EGR flow proportions as a way to meet emissions targets.

 

[Roadie]

I took a ride to Sky Line drive this past weekend with my friend on his 2025 Harley Street Glide Ultra. Both of us got over 52 mpg on our 575 mile road trip.

My Gold Wing got slighty better fuel mileage though, the Harley has a little bigger fuel tank than my Gold Wing so both bikes has about the same range. Not bad the 7 year old 6 cylinder tech edges out a 2025 Vtwin with fuel efficiency.

 

[apes 115]

This may be old hat to some, but I finally satisfied my curiosity about fuel mileage difference between the older and newer Goldwings. Today 4 of us went on a ride at Rockies Gold. Jerry Wells, Brian Norwood, David Trail (all on Gen 6 Wings) and I on my 2012 Gen 5 Wing all fueled up at the start and went on the same run together. All 4 of us were pulling identical Tailwinds.

We all fueled up together when we returned to Montrose. My 2012 got 41.0 mpg. David got 47.7 mpg, while Brian got 49.4. Jerry said he didn't look at the final fill. Regardless today the Gen 6 Wings got 15% to 20% better fuel economy.

I was curious, and the results were about what I expected. I am proud to have able to research this data for you.

Good job, good to know

 

[apes 115]

Yes, explain to Mrs Glockjock that a new bike will pay for itself in fuel savings alone.

And you're helping the environment