+1. If this is for pictures or trial builds then there's no problem. If it's for a trip to the bike shop for an adaptor fine. If you intend on running like this long term I would not say that it's safe and the resultant failure on the road could see you being brown bread under a vehicle.pete_mcc":2mk3uxn8 said:
Quick answer needed.....
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We_are_Stevo
Old School Grand Master
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gtRTSdh":tsjuxgvo said:
So what, exactly, is going to fail? And why?
We_are_Stevo":17hvzj6c said:
An Ahead steerer is solid and designed to have a stem levering on the tube above the headset. A threaded steerer is designed to support the stem from inside the tube, over a much greater length than the Ahead steerer.
Thus if you use a threaded steerer with an Ahead stem you are basically using a solid steerer with the wall section reduced in such a fashion as to encourage it to break. Have you ever done a charpy or izod impact test without the notch? You know, that 60 degree notch that's the same angle as the thread cut into a threaded steerer.
I think the below sums it up nicely.
http://www.youtube.com/watch?v=EbTZy7rbt7k
Bearing in mind the steerer is steel and thick, there is some margin of safety. However, in the long therm you are likely to risk fatigue cracks starting in the threaded area.
Personally I would be comfortable provided only if half the area under the stem was residual thread. This would be a relatively unstressed area of the steerer.
Personally I would be comfortable provided only if half the area under the stem was residual thread. This would be a relatively unstressed area of the steerer.
RadNomad
Senior Retro Guru
In the below diagram i've shown the contact surface length of unthreaded portion as blue arrow "A" and the contact surface length of the threaded portion as "B". In this example the available contact surface length "B" is only 26% of the length "A", which suggests clamping an ahead stem onto a threaded steerer would be a far weaker clamp and fail sooner (i.e. stem rotating on the steerer) than the correct installation due to the significantly reduced surface area.
Admittedly this diagram is ISO thread and i didn't take the time to research what thread type a cycle steerer might have but you get the general point, there won't be that much difference.
Bottom line is that the OP is proposing a bodge. In my view a bodge is fine to get you home if you're desperate, but not satisfactory as a permanent installation.
Admittedly this diagram is ISO thread and i didn't take the time to research what thread type a cycle steerer might have but you get the general point, there won't be that much difference.
Bottom line is that the OP is proposing a bodge. In my view a bodge is fine to get you home if you're desperate, but not satisfactory as a permanent installation.
