Originally Posted by
cat0020
I've also tried the hidden same hidden stem extender, it is made of aluminum, the center bolt is aluminum, too.. easily stripped when you try to torque it down. Also it is more difficult to have proper tension for it to secure the headset without a top cap that's threaded.
I've used quill to threadless stem adapters, but not setup as hidden, on a couple of bikes. The adapter/extender was aluminum, but the wedge and the bolt were steel.
They function the same as an aluminum quill stem but with a upper section that will accept a threadless stem. I can't imagine anyone selling an adapter/extender where all the components were aluminum.
John