Old 03-06-15, 01:30 AM
  #22  
willydstyle
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Originally Posted by Al1943
New Colnago C50 build, last bike I plan to buy, ever. Anxious to go for I ride all I needed to finish was to mount the stem on the carbon fiber steer tube. Stamped on the stem near the pinch bolts was "8 nm". With my new 1/4" drive Park TW wrench I gradually brought the torque up alternating between the two bolts. At 8 NM I get a loud pop and a 4 inch long crack. The new replacement fork was $800+. Lessons learned: 1) the torque value good for the pinch bolts was not good for the material being pinched. Mistake 2 was that I had not used the longer Colnago expansion plug but instead had used a plug that did not support the backside of the steer tube behind both pinch bolts. And 3, I had cut the tube 1/8 inch below the top of the stem with no spacer above the stem. Five NM is more than enough torque to mount a stem to a cf steer tube.
I know its a 10 year old story but one still worth telling.
That is an expensive frakking lesson.
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