How much weight do you honestly need to save? I prefer the strength of steel to support the pleg.
Do you run steel rims? Steel stem?
I am not sure this is a strength issue, I thought it was a cost issue? For how cool the plegs are they are a very low price of admission. I wouldn't expect to get aluminum machining for as little as I paid for the plegs.
Still puts alot of stress on it, i would rather the confidence that steel wont bend and cause the peg to give out or bend upwards and cause serious injury....or death!!!!!!!1
I'm with you there if that's really an issue
Usually when considering materials for a product, we generally follow the principle that:
If its more likely to bend than snap, use aluminum
If its more likely to snap than bend, use steel
I am gut feeling, with no actual evidence to back me up, that the weak spot here is going to be the plastic itself and not the insert. I could be very wrong, and would love to be pointed to anectdotes showing how plegs have failed. I did read where someone tried to make just a washer and a collar and snapped the pleg at the mating end