That time I ignored bearing preload specs and paid for it

I always thought preload specs on headset bearings were just optional guidelines, not hard rules. Last week I skipped the torque wrench on a customer's carbon fork install and now the headset's got a horrible notch after 3 rides. Has anyone else had an expensive lesson from ignoring the numbers in the service manual?

2 comments

2 Comments

the_miles17d ago

3.5nm on a stem bolt? That's insane you actually freehanded it. I always torque those to 4nm even if the fork says 3.5 because one extra click feels safer. But ignoring headset preload completely is a whole different level of gambling. You basically let the bearings rattle around loose for three whole rides before they started digging in.

taylor_flores17d ago

What's the point of even having a torque spec if you're just gonna add half a newton meter because it "feels" better lol? I've stripped a stem bolt going from 4 to 5 on a gravel bike once and it was a total pain to drill out because it was recessed into the faceplate. And the headset preload thing is wild, like those bearings probably sounded like a loose jar of marbles on every bump before they started eating into the steerer. I've always set preload by feel with the front wheel off the ground and the fork fully extended, then back off just a hair so there's zero play.