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Re: Giant Propel SL Top Tube Crack. Is it too fragile?

Posted: Sat Nov 03, 2018 4:26 pm
by efeballi
I could be wrong, but AFAIK lower grade carbon frames are more durable than high grade ones.
Higher wall thickness and higher epoxy ratios create a less brittle structure in out of plane stresses(outside impacts) and also reduces the “soda-can” effect, which is the feeling you get when you can squeeze the top tube with your thumb.


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Re: Giant Propel SL Top Tube Crack. Is it too fragile?

Posted: Sat Nov 03, 2018 4:26 pm
by Weenie

Re: Giant Propel SL Top Tube Crack. Is it too fragile?

Posted: Sat Nov 03, 2018 6:45 pm
by mattr
efeballi wrote:
Sat Nov 03, 2018 4:26 pm
I could be wrong, but AFAIK lower grade carbon frames are more durable than high grade ones.
Pretty much. Stiffer/higher grades tend to be more brittle. You can mitigate by how you lay up and what resin % you use and so on. But essentially higher grade composites = less tough.

Thats why frames tend to not use all of one high grade, usually have a mix T700 and T800. Can stiffen up key parts by swapping 100 grams of low grade for 100 grams of high grade and so on.

Not a simple equation, but generally speaking.