Posted by Dimebag on February 02, 2019 at 08:46:55:
The old thread http://www.meshingwithgears.com/wwwboard/messages/1067.html
For gears with relatively large number of teeth, it seems there’s no fundamental strength difference between the two systems. For gears with a small number of teeth, in the constant tooth depth system the teeth are noticeably shorter at the heel, the contact ratio is smaller, the gears tend to be weaker.