As for Speedplay pedals,
↑Here's an exploded view like this.
↑Edit: The positional relationship between the shaft and cartridge ball bearings is wrong.
The two bearings on the right end are positioned one more step to the right.
With cartridge bearings in hubs and pedals and such,
almost 100% of the time, there are commercially available products in matching sizes.
Speedplay pedals have three bearings inside,
but until now, the needle roller bearing among these
was difficult to source. However, I found a good bearing supplier, so
stable supply is now possible!
The left side in the image above is brand new.
Before replacement, the needle bearing had rusted and
even trying to get by with regreasing was impossible as it was grinding badly,
but after replacement it returned to smooth rotation.
↑This pedal shaft is titanium, but generally speaking,
when ball bearings are in direct point contact with titanium pedal shafts,
the titanium gives way and quickly develops "spalling."
In the case of Speedplay, with the needle bearing's line contact,
the shaft doesn't fail as quickly as it would with ball bearings.
However, even so, it's not good to keep using rusty or worn bearings,
so if the damage is severe, I recommend replacement.
↑Here's an exploded view like this.
↑Edit: The positional relationship between the shaft and cartridge ball bearings is wrong.
The two bearings on the right end are positioned one more step to the right.
With cartridge bearings in hubs and pedals and such,
almost 100% of the time, there are commercially available products in matching sizes.
Speedplay pedals have three bearings inside,
but until now, the needle roller bearing among these
was difficult to source. However, I found a good bearing supplier, so
stable supply is now possible!
The left side in the image above is brand new.
Before replacement, the needle bearing had rusted and
even trying to get by with regreasing was impossible as it was grinding badly,
but after replacement it returned to smooth rotation.
↑This pedal shaft is titanium, but generally speaking,
when ball bearings are in direct point contact with titanium pedal shafts,
the titanium gives way and quickly develops "spalling."
In the case of Speedplay, with the needle bearing's line contact,
the shaft doesn't fail as quickly as it would with ball bearings.
However, even so, it's not good to keep using rusty or worn bearings,
so if the damage is severe, I recommend replacement.