Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: rogerzilla on 18 September, 2019, 10:48:27 pm
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1A stem of unknown vintage but 26.4mm clamp, so pre-mid 90s. Has the alloy expander bolt and wedge. Is it safe? It doesn't look damaged, the hex head is undistorted and the threads are excellent. I don't think it's been overtightened. Does anyone know the correct torque? I'd guess less than 5Nm.
Should I improve the odds by polishing it or (a tip I've read elsewhere) "setting" the wedge with a steel expander, if I can find one to fit, then replacing with the alloy bolt?
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IIRC these bolts are aftermarket ones, I forget who made them, but they may have been anodised? In which case no, you shouldn't polish it.
Is it safe? Probably; after all the stem will have a conical wedge and this usually jams itself pretty well. Probably you could tighten the bolt and then back it off to a lower torque without the wedge working loose. However the bolt will see fatigue loads if the stem is a loose fit in the steerer. Belt and braces suggests winding a few turns of PTFE tape onto the stem before lowering it into position. If you apply it in the right way, the turns form a kind of wedge which helps stabilise the stem and helps deter moisture ingress too.
cheers
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I think only the 1R had the alloy expander bolt.
Someone might have taken one from a 1R and put it in the 1A.
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1A stem of unknown vintage but 26.4mm clamp, so pre-mid 90s. Has the alloy expander bolt and wedge. Is it safe? It doesn't look damaged, the hex head is undistorted and the threads are excellent. I don't think it's been overtightened. Does anyone know the correct torque? I'd guess less than 5Nm.
Should I improve the odds by polishing it or (a tip I've read elsewhere) "setting" the wedge with a steel expander, if I can find one to fit, then replacing with the alloy bolt?
Is it a wedge or a cone at the base of the stem?
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Most people over-tighten quill stems. Tightened, you should still be able to move them with moderate force.
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1A stem of unknown vintage but 26.4mm clamp, so pre-mid 90s. Has the alloy expander bolt and wedge. Is it safe? It doesn't look damaged, the hex head is undistorted and the threads are excellent. I don't think it's been overtightened. Does anyone know the correct torque? I'd guess less than 5Nm.
Should I improve the odds by polishing it or (a tip I've read elsewhere) "setting" the wedge with a steel expander, if I can find one to fit, then replacing with the alloy bolt?
Is it a wedge or a cone at the base of the stem?
Cone, as usual with Cinelli (except their steel stems)