8

Do you put anything under the clamp on the carbon to protect it? In the past I've tightened brakes on MTB handle bars to much and wrecked them so I'm wondering.

  • I've mounted lights on carbon forks and the thought of over-tightening the clamps made me wince every time... (I put a strip of old tube underneath, but no idea if that's the best thing to do) – darkcanuck Sep 23 '10 at 4:19
  • Carbon seatposts are also another part to be careful with. – Dana the Sane Sep 23 '10 at 13:10
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    My understanding is that parts have to be the right size for carbon, and fit to the correct torque (so you need a torque wrench) and carbon assembly paste. You don't use shims or straps or any tape between components and bars/frames because that means you have the wrong size. – Criggie Feb 25 '18 at 4:42
6

Carbon compound can definitely help. As the following link points out, it helps you avoid 'over torquing' to ensure that the component doesn't slip.

http://www.finishlineusa.com/products/fiber_grip.htm

In my personal domain, if there is carbon and carbon, or carbon and some other material, thou must use fiber grip. And a torque wrench. No questions.

4

There's no need to treat the underlying carbon before installing a clamp-on front derailer. Fiber Grip or a similar assembly compound helps increase grip under lower torque, but this does nothing to prevent you from over-tightening the bolt and crimping the tube. A torque key and patience are required for that.

I recommend picking up a pre-set torque wrench like this:

enter image description here

Example is from https://www.amazon.com/Ritchey-5Nm-Multi-Torque-Key/dp/B009F93S9C but many bike shops have similar tools.

It's small enough to fit in a saddle bag and I bring it with me on rides in case anything slips and needs re-tightening.

  • 1
    Concur - so much stuff on a modern bike is ~5 Nm its a valuable tool to have. The "well-calibrated elbow" is sometimes not good enough. – Criggie Feb 26 '18 at 6:04
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    Excellent first answer too - I've edited it a little to bring an image in-line, because they're stored on imgur servers. That way if the linked product goes away, future readers will be able to see what you meant, and find a suitable replacement. – Criggie Feb 26 '18 at 6:07

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