Modern Vespa

Here's a graph for Christmas.

What is it? It's speedo (vertical km/h) vs fuel use (horizontal km/l). The green is showing 'stable' speeds'.

roughly it shows that at 100kmph the fuel use is 30km/l. Then as the speedo ramps up towards 130 the fuel use drop towards 20km/l. Obviously wind resistance is gaining in significance (as predicted)

Below 80kmph it's a lot less clear (but does roughly follow the pattern) because stable speeds below this can be achieved at a range of rpm depending on if you accelerated or decelerated to reach a given speed and how quickly you accel/decel. But we can still see that there's a lot of 40km/l around 60kmph.

at lower speeds like 40 or so I don't seem to have a lot of data keeping a steady speed :shrug: But I do get a sense from looking at a lot of this data that the efficiency is dropping off compared to 60ish.

Conclusion 60-70kmph is the sweet spot. (I'm guessing this is best when accelerating gently to this speed range - probably could filter the numbers a bit more to confirm this)


Data and graphing is as always performed with my VespaSnoop app and my 2019 Supertech

Yup - best fuel economy is found when at the lowest speed possible while in the highest gear. Depending on the scooter, this can be anywhere from 30 to 45 mph, so consistent with your real-world findings.

Your graph is interesting. What it reveals is that at lower speeds when free and constant flow is not possible fuel consumption is unpredictable.
Or in other words: forcing traffic into conditions that hinder constant flow is a bad idea with respect to fuel consumption.

The best fuel mileage I have gotten is on rides in the mountains.

Mid 90's mpg on the Yamaha Xmax in both North Carolina and Colorado mountains.

The oddity here is that speeds in Colorado are much higher than speeds on the much twistier roads in North Carolina.

Not much stop and go in either location.

The other difference is much higher altitudes in Colorado.

There must be a correlation between altitude and fuel mileage.

Bill

Le Wife has complained for a while that the average MPG of her car (2013 Honda CR-V) has dropped over the years, and considers it a matter of the car's age and mileage–it was the first car she'd bought brand-new in a long time. I countered that it's more a matter of her driving habits and living situation, since (1) when she first bought the car, she was still living in NYC (as was I), (2) the bulk of her driving is highway-based, and (3) she frequently drives over the CR-V's own "sweet spot", which I've estimated to be between 60-70mph, and (4) she does have a habit of constantly varying her speed, rather than set a constant pace, which definitely has a negative impact on fuel economy. Whenever someone else has taken the wheel (even her younger son, who has a heavier right foot, but much-smoother and more consistent manner), the difference in mileage is noticeable.

I've observed this in my riding experience as well, with low-speed, stop-and-go riding having a noticeably negative effect on mileage, while high-speed runs at a consistent speed had a relatively minor effect. As the new bike will offer hard, observable stats to this effect, I'm looking forward to more accurately graphing this stuff.

Regional and seasonal formulations of gasoline, separate from octane ratings, can also significantly affect mileage measured from tank to tank.

And so does eating a lot at Christmas 😀

My above graph was from a single 4 day 2000km road trip. Graphs from every other ride i do shows the same pattern

Now this is far more interesting than the fuel consumption graph...

Where did you go this time?? Are you allowed to cross borders down there?? I'm stuck at work ATM and afraid to cross into NSW and not being able to come back...

this was last few days of November. small amount of NSW included. Pics at https://www.instagram.com/steelbytes scroll back to 26-29/Nov for daily dumps

Another great trip by the look... I wish I was down there with you sharing the experience...