Originally Posted by
oneclick
I have several versions[1] of the roller-bearing Stronglight on various bikes and my experience matches that of pretty much everyone else I've read; yes it's not as big a concern.
It's just about zero concern, in fact.
[1] there's a "composite" (=plastic) version, I think it feels different, don't like it as much.
The Delrin version was the B-10. It used the same rollers and floating steel races as the A-9, but Delrin instead of aluminum for the crown race, head tube pressed pieces, and threaded cup. It was a few grams lighter than the already quite light A-9 model, but the plastic pieces weren't as solid-feeling as the aluminum pieces in the A-9; to me, it always felt like the headset was a little loose. But if every gram counts, you need the B-10.
FWIW, Tange made a hybrid roller/ball headset for IRD:
https://www.somafabshop.com/shop/297...gory=788#attr=
The rollers were in the lower race, which handles all the load, while the balls in the upper race keep things in alignment.