Just found this crack on my stem, also cracked one of the bolts off. Torque requirements said 8.8nm and this was only at around 7.5, am I misreading these torque specs? How I ensure I don’t crack anything especially on carbon parts
by ronocrice
Just found this crack on my stem, also cracked one of the bolts off. Torque requirements said 8.8nm and this was only at around 7.5, am I misreading these torque specs? How I ensure I don’t crack anything especially on carbon parts
by ronocrice
13 Comments
Part failure can be caused by a lot of things, not just over-tightening. If this part was crashed or defective, this can happen
How old is the stem?
I’ve never seen a stem require 8nm. That stem is also most likely a decade old. Things break over time. Just be glad it was in your workstand and not descending down a mountain.
8.8 is awfully tight for things like this and odly specific. Usually 4 or 5 nm… never with a decimal.
Do you have a pic of the said torque spec? 8.8Nm does not sound right and have yet to come a cross a stem that requires such a high torque.
I know that stem well and it’s at least 15 years old.
I think it’s time is done
Did you perhaps use any type of grease on the thread of the screws?
Unless it’s specifically mentioned that it needs grease threads torques are usually “dry thread” torques. Grease will make the screw tighten easier, which can cause the torque setting to be reached at a far too high clamping force. Normally if a thread should be greased, the type of grease would also be mentioned as that is of influence as well.
And yes, as others have mentioned – 8.8 is a very high and unusual torque for carbon parts on a bike. 8.8 is commonly used as an indication or specification of a screw of bolt strength.
6.8nm is 5ft/lbs. No chance it was a bit hard to read?
skill issue. for using a decade old carbon stem, mainly.
FSA strikes again…
My stem bolts are about 6 nm. Which means they should take about 10-12 without issue.
This is just a thing that happens. Go get a cool colored stem for $100 to replace it and never think about this again. This is about the most benign thing that can happen to a bike.
Did you lube the bolts? Stems are dry-treads.
Applying lubrication to any dry-bolt will reduce the torque required to achieve the same bolt compression by about 50%.
Are you sure your torque wrench is working properly?
Breaking a bolt sounds like you applied very high torque. Do you know what 8.8N·m feel like?
Does the stem actually say 8.8N·m or does it only say 8.8?