I just bought a 2019 FX 7.2 three months ago. I'm over 6 foot and around 265 lbs. I'm a total data nerd, so I started tracking rides and performance immediately with the bike to find out what reality was.
Here are the ride stats from my last 15 rides to give you an idea of the range of the FX:
If you are substantially lighter, you might go a little farther than this. There is a guy that weighs 155 lbs on the Facebook Zero Motorcycles Owners Group that says his FX gets better mileage than what I get on mine. Most everyone else I talk to says my numbers match theirs and some even say they don't get as much as I'm showing above.
Basically, if you want to make 60 miles, you keep your average speed under 30 mph. If you want to go 80 miles, keep it under 25 mph. If you want to go 100 miles, keep it under 20 mph average. Going over 30 mph average will make it drop fast. Also, keep in mind cold temps reduce these numbers and higher temps increase them a bit.
I did another ride this week where I knew it was going to be a short ride, so I hammered it all the way:
Total Distance: 42.10 mi
Moving Time: 1:06:16
Average Speed: 38.1 mph
Elevation Gain: 1,798 ft
Max speed: 88.1 mph
Avg Air Temp: 81.5F
100% of the charge used.
This is what the speeds of this ride looked like to average out to 38 mph:
You can see at the end of the graph where I was holding it wide open throttle and the bike was just continually slowing down as the charge faded away.
On this last ride, I just went out to have fun and run off the full charge of the battery. At one point you can see on the graph, I ran the bike wide open throttle for a couple of miles (@88 mph) and ran it into thermal protection mode doing so and had to slow down for a while. That ran the charge down a fair bit.
After that, I went into town to run some errands and that's the slower mid section of the ride. But even, after getting the charge in the 30% range, it still had enough to hit ~70 mph on the way home. Once I got sub 10%, I could no longer hit 70 mph. It was 65 mph, then it keeps dropping fast from there. At say 6%, it won't hit 50 mph anymore. By the time I got to my street, I was at 0% and it wouldn't go over 30 mph.
That's a weird thing to get used to with electric bikes. Unlike gas bikes where the performance is consistent to the last drop of gas, the performance of an electric bike deteriorates as the charge goes down. At 100% charge, the front wheel flies up on its own almost as it races up to 80mph. Around 30%, 70 mph becomes the max speed. At 7% charge, I can barely hit 40 mph and limp home. All stuff I wish I would have known prior to buying a Zero and things to factor in on a ride.