Alan B wrote:John in CR wrote:A 17" moped rim has a 17" rim, and the OD of the wheel will depend on the tire, but in all likelihood it will be greater than Zombies's. It's not like the retarded bike convention for tires.
Yes, of course you are correct. I used 23.5" for the tire diameter in my calculation above.
You caught me not paying attention to the voltage difference, though that's probably a bit big for a moped tire. My moto tires on a 17" are right at 23.5" and they're a lot higher profile than the moped tires I've seen. The huge difference in wind resistance will offset that in the other direction.
Also, once you get into those speeds tire size becomes pretty unreliable. eg My bike that Luke had up to 61mph when he was down pushing 120A battery side through the controller at 74V nominal (20s) had that 23.5" diameter wheel I mentioned above. My daily rider with the same motor is much lower and runs a 20" OD wheel, a moto 14" rim and tire, and it comes very close to the same top speed with the same voltage but at only 75-80A battery side. The moral of the story is that overcoming the wind is everything. If I tried that hubbie Luke used with the 17" rim on the bike I'm currently building, I have no doubt it would push through 70mph. Don't forget, I weigh 250lbs too, so weight has little to do with speed, except on hills, but it matters for acceleration.