Originally Posted by
Kontact
The problem is that they can't really control for stupidity. None of these steerers might be a problem if they are used correctly, but none of them are proof against overtightening or using the wrong type of stem. Maybe they found these instructions decrease the amount of knucklehead damage. I don't know - but carbon steerers are nearly 20 years old.
To me, the concern is inconsistency in documentation, as well as margin of error for safety.
I'm reminded of the difference between ibuprofen and acetaminophen (paracetamol to non Americans). It's apparently perfectly safe to take 3x the over-the-counter dosage for ibuprofen - in fact, prescription strength ibuprofen is pretty much 3x strength Advil, and is used as an anti-inflammatory.
Compare that with 3x extra strength Tylenol, which is very, very dangerous, and 4x has been proven to be fatal.
NOTE: DO NOT take my comment above as medical advice - ask your doctor before taking above any recommended dosage on the bottle!!!!
The compressive strength of an alloy steerer can probably withstand multiples of 5nm before crushing.
It seems like the compressive strength of a carbon steerer might not withstand 1.5x the stated 5nm - or even 5nm, for that matter.