Metal Pedal Fatigue...
 

I commute daily with toe clips/mouse traps. My 2015 Charge Plug came with this type of metal platform pedal (but NOT this brand):
https://cimg4.ibsrv.net/gimg/bikefor...61ff282add.jpg
Five years of near daily commutes and weekend rides and this happened:
https://cimg2.ibsrv.net/gimg/bikefor...787e4c10a0.jpg
The metal at the rear broke off. (I had removed the toe clip before the photo). The metal perimeter around the left pedal was cracked and on its way to breaking, too.

I checked the screws that held the metal "perimeter" to the main "H" portion on both pedals, and they were all snug.

I replaced 'em with a similar type and all's well for now.

My other two bikes are much older, a 1997 Nishiki, and a 1984 Nishiki, and I never had any pedal issues on them, although the metal around the hole for the crank bolt on the left crank arm on the '84 Nishiki started to break after 33 years, and I replaced it.

Do the pedals on your older Nishikis use steel rather than aluminum for the broken pieces?

without inspecting the fracture(s), hard to say if the pedal had a manufacturing defect of some sort that initiated / accelerated the failure. Stamped and bent aluminum in an inexpensive consumer product like a bicycle pedal likely doesn't get intense scrutiny for small fractures. I'd guess the failure began with the pedal cage "teeth" and maybe advanced to failure by a strike against a rock, curb or something similar.

Better to fail like it did than have a pedal axle break, which, while not super common, is not rare. .

After 5 years of commuting, cheap stock metal pedals can fail.
Who knew?
:thumb:

That's a casting. Get a tiny crack in it and it has no grain structure to resist further spreading of the crack. Failure is sudden.

I can't tell you how many pedals we rode on just the spindles as kids.

you had spindles?

The pedals are often the cheapest part that comes on new bikes. People look for sealed bearing hubs and to what SHimano group the derailleurs belong, but ignore that the pedals are plastic and have bearing that feel like they are lubricated with sand. It makes less difference for many recreational cyclists, who will take off the stock pedals before the bike is ridden, but if you buy a bike today intending to ride to work tomorrow for the first time, you may be taking a chance with some dangerously poor quality pedals.

Those are cage pedals - a section of the cage (the metal perimeter) broke.
Mouse traps?
Five years of commuting and weekend use is not bad. But usually bearing go bad before structural parts.

Possibly.