What would be the difference in torq / speed between normal 273 and the one with 50mm magnets assuming they both work with my Sabvoton 72200? BTW what constant power 72200 can produce?
''difference in torq / speed between normal 273 and the one with 50mm'' I think negligible difference with your controller and assuming that your ebike is considerably light. Maybe you would notice bigger difference in some heavier motorcycle. Maybe what you would notice is additional several kg in your wheel but is depends on what surface you would ride.
btw, there is no normal 273 and with 50h. All they are normal nominal max good strong small big powerful etc They are just different motors, some have 205 diameter some 260 some 273 etc, magnets 28mm - 80mm...
Something constant is assuming certain conditions are present and set in advance. So what can be constant if conditions are not the same... There will be different temp, weight, road inclines. Usually you don't do constant riding in reality, load always fluctuate.
72200 maybe it can work with 70amp constantly, it deptens, probably manufacturer sets these numbers... there is no point searching what it can do constant, because we won't meet those circumstances in our day to day life anyways unless you plan do some long traveling and keep controller in certain conditions then yes, you would benefit at these numbers but you anyways would try what you have and if it overheats than you would change something. And that something usually is heat decrease by some means ie increase cooling in some way, spread that heat somehow and you will change that constant therefore it is not constant.
Let just say that how I see those components in practise.
273 40h ~3t is ok with 72200 but the motors can take up to twice power the controller can provide. I see people bursting it up to 30kw.
273 50h can do +10kw what 273 40h can do in bursts. But this is all about bursts... constant is whole another story. That is why they are declared as 3kw 4kw 5kw 6kw 8kw nominal. Nominal could be similar to constant but nothing is nominal or constant unless certain conditions are met beforehand.
So I would say if you building light ebike and want crazy fast machine than take 273 40h. I see no point for 50h but if it won't hurt (additional weight and price) just for having more potential in future. Your current controller won't be up to the task of potential motors capabilities anyways. Well, axles, if you care you should now that these hubs have different axles. Hubs meant for 200mm dropouts have thicker ones. If you plan to travel high speeds than you could benefit from stronger axle.
Fast motor means less resistance inside, less resistance inside means you need to pass more currents to get that crazy fast acceleration and it means you need more powerful controller. If you want to go fast it it needs top components. All three of them: motor, battery, controller. At high power it gets heavier expensier and way way more wasted energy, because of constant fight with air.
