Well, there is another issue. Only a complete ----------- would ride a bike path shared by walkers or slower bikes at 60 kph. Rude enough on a well used path to even travel 30 kph.
But, maybe you won't have others on the path. Common enough for nobody to be using them. If alone, I'll go 40 kph on my local paths. But I slow if I encounter somebody. Cops never give me a look at 40 kph. They have at 50 kph.
So, I also recommend building for a max speed of around 40-50 kph. It's easier to ride courteous on the path if that's needed, It's far more reliable on every component of the bike, and you won't need near as much. That 30 mph is easy as pie to get with a 48v system. Nearly all do 27 mph and many go 30 mph on 48v. So you will save hundreds on the battery if you stick to 48v. 60 kph will put a shitload more wear on rims, tires, spokes, brakes. You'll spend twice as much time on weekly maintenance if you haul ass. At 40 kph speed, you can go months with no maintenance once you get your wheels settled in and tuned.
Seriously, its plenty fast enough, and going faster takes an incredibly larger battery. So, if you change your top speed, it's easy as hell. Any decent hubmotor, and up to 30 amps controller and you are all set. The Mac 10t and 48v battery is a good solution. The dd motors take off a bit more sluggish, but work fine if you have few stops along the way. The dd motors can be more reliable, not pushed hard they can go years with nothing but spoke tuning. Either will work fine, just look for at least 1000w, and 48v. Rear motor of course.
In a 48v battery, you will need more than 10 ah of battery to make it in all weather. A 15 ah would be ideal. If you ride on the slow side, say 20 mph, then a 12 ah would do it fine. One way I mean. Your travel time should be about 45 min, at 40 kph including stops. I found less than 30 min too short, enjoying the ride too much to want it to end, even on the return home. Often rode even slower on the return, to make it last even longer. My commute was 25 k.
