Are universal pedal axles weaker than standard axles? If so, should they be avoided?
These are inexpensive pedals so let's focus on inexpensive normal, solid axles vs these universal pedals.
Each pedal comes with a 1/2 inch and a 9/16 inch adapter that must be screwed into the pedal body.
The left pedal adapter threads in with a left hand thread, the right pedal adapter threads in with a right hand thread.
Edit 4/10/2020
Would they be strong enough for any of the following applications?
Could these pedals be strong enough for some applications not displayed below?
The following bikes were chosen because they come from bike shops with roughly comparable inexpensive plastic pedals.
All the bikes are Trek because it was easy to find a wide variety of Trek bicycles. This is not meant as an endorsement of Trek.