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Watch out for those new carbon seatpost clamps on gravel bikes
I was finishing a full build for a customer at the shop yesterday, a high end gravel bike with a carbon frame. Torqued the seatpost clamp to the spec printed right on it, 5 newton meters. The customer picked it up, rode about 10 miles, and came back with the seatpost slipped way down. I checked it, re-torqued it, and sent him off. He came back an hour later, same problem. That's when I noticed a tiny, almost invisible crack starting in the carbon around the clamp slot. The printed spec was wrong. I called the frame maker and they confirmed a batch had the wrong spec printed; it should have been 4 nm. That extra 1 nm of force over-tightened it just enough to start crushing the carbon. Had to order a whole new frame section for the guy. Has anyone else run into a misprinted torque spec causing real damage?
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mitchell.shane1mo ago
That 1 newton meter difference is a killer on thin carbon. I started putting a strip of clear frame protector tape around the seat tube before clamping, adds just enough cushion. Always cross reference the torque spec online with the manufacturer's website now, never trust the printed decal alone.
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Ask the manufacturer what batch numbers had the wrong spec printed on them? That way you can warn people before they wreck their frames too. Would be good to know if there's a serial number range or something specific to check.
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