These plates tolerated 6kW-8kW of very torquey power for a good amount of time, and pretty strong regen as well ( 700-1250w ).
In the end when i dismantled the magic pie bike and sold it's componentry, after almost 2 years of abuse, i still had to bang on the axle to get the motor out of it's dropouts. I looked at the torque plates and they were still perfect. I couldn't believe it.
I've been preaching this method of making torque plates for mid-high power setups for a long time now. They might not have stood up to a Crystalyte 54xx or cromotor hubzilla, but they were pretty effing strong.
Always overbuild your torque mounting bits. You'll pat yourself on the back later rather than kicking yourself in the ass as you gradually pump more & more power into your motor