How strong are pedals?

Question

Pedals are obviously a critical interface with the bike. A broken pedal axle would be catastrophic, most likely causing injury or even death, especially considering that pedal failure would really only occur during massive impacts. In light of this, is there a standard for how strong pedals and pedal axles have to be? Are road/XC pedals necessarily weaker than their burlier MTB counterparts? I've never seen a pedal marketed with a maximum load rating or anything. Pedal breakage, although rare, does occasionally occur for reasons other than manufacturing defects, so it is a valid concern.
Hypothetically (or in real life!), would I be able to safely ride a road pedal down Red Bull Rampage or some other similar event with gigantic drops and jumps?
What about other components of the pedal interface? The threads? The threaded insert in a carbon crank? How about the cranks themselves?

juhist · Accepted Answer

What about other components of the pedal interface? The threads? The threaded insert in a carbon crank? How about the cranks themselves?

I'll use the "pardo" durability index to answer. The durability index is based on the number of failures at http://pardo.net/bike/pic/index.html.
For pedals, we see three failure events.
For cranks, we see 55 failure events.
So it seems based on this that the crank pedal eye fails far easier than the pedal connected to it.
One reason is that the pedal to crank attachment has a design flaw, and the crank, being made of aluminum, is the component that suffers as opposed to the pedal spindle made from steel, a far stronger material. The design flaw can be seen from the left pedal having a left hand thread -- a proper design would not be sensitive to threading direction. It can also be seen from old cranks, from which the removal of pedals sometimes is a Herculean effort and even when it isn't, the pedal eye of the crank is visibly worn. The pedal to crank pedal eye attachment should have a 45 degree taper, similar to automotive lug nuts.
Of course, non-catastrophic failures of cheap plastic pedals happen often. Those are used only in inexpensive bicycles intended for little kilometers in their lifetime, for light riding.

Criggie · Answer

The part that fails seems to be the thread in the crank arm, and that mostly due to poor installation with cross threading and/or riding it loose, if we go by the number of questions about pedals asked on the site.
Bearings will wear out over time naturally, due to usage.  This gets accelerated by riding in the rain, dirt, and storing the bike outside.
In all my life I have bent one pedal axle, and while it was perceivable, it did not stop me riding that bike for years more as a teenager.   I have also lost a Look pedal body once, when the retainer ring unthreaded and the whole platform fell off the pedal axle while I was walking the bike.
I would estimate that outside of collision damage, any pedal will last for many years until gradual wear claims it, in bearings or clip interface or similar.

I'd suspect that the subgenre of cyclist who is most likely to bend a pedal axle would be a BMX rider who is doing stunts and tricks.

How strong are pedals?

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