Doc_Wui

I didn't realize my old fork was steel when I replaced it with a alloy suspension fork. What concerns me is that I wasn't thinking and cut the new fork to the same stem length. It's a 1 1/8" threadless. The stem clamp is unusually narrow, in my opinion, only about 3/4 inch high. As soon as I saw that, I wished I had also replaced the stem clamp.with a higher one.

Wondering if there will be enough clamping force on aluminum with the narrow stem? I typically use stems that are a lot higher. The aluminum tube is pretty sturdy though. I had to squueze down my star nut to get it down the hole.

Brocephus

if you're talking about the 1 1/8 steerer tube on your new suspension forks, are you sure it's not steel? I've always known them to be steel rather than alu.

fietsbob

more expensive Suspension forks use aluminum tube for the legs and steerer..

you can use an expansion nut fitting ( needed for carbon steerers , instead of the star nut

and not scratch the inside of the fork steerer...



I used a BBB BHP 21 internal stem raiser and it goes in instead of the star fangled nut.. ..


..

Doc_Wui

Riding my other bike in Chicago over the weekend with hundreds of other bikes around me, I noted quite a few narrow stems on other bikes. Guess I'll not worry.

I replaced another fork last year, all steel, and when I tool it apart, I saw that the thin steel steerer tube was slightly dented from the clamping force of the stem. That's when I started wondering about the robustness on these threadless assemblies.

Andrew R Stewart 

Threadless stems have much more surface area, then quill type stems have, that contacts the steerer and places a compressive force onto the steerer. A quill stem concentrates it's expansive forces on a much smaller surface area. The only steerers that I've seem threadless stem clamping compression distortions are carbon, not metal. Steel and AL have fairly high compression strengths, depending on how the layup of carbon in a steerer it's compressive resistance can be all over the board. Generally though carbon frames/forks are made with minimal material as a priority (less weight). This is one reason why a compression plug is used with carbon steerers. Now steel has a higher tensile (stretching) strength then AL typically has, which is one reason why threaded AL steerers are so few.

Of course overtightening any stem is bad and can lead to different kinds of failure modes. Andy

carlos danger

This thread is simply too risky to even respond to since i have no idea what you actually mean, and no one else does either. if possible post pics and encircle in red.