Setting headset bearings

On 5/1/2019 6:29 PM, bob prohaska wrote:
John B. wrote:
One thing I have noticed is that the play in the threads is sufficient
on many bikes so that if you hand tighten the lower nut so that the
fit is just perfect and then tighten the lock nut, holding the lower
nut stationary, the bearing is too tight.

I should probably emphasize that there's no problem with the workings
of the headset bearings, the bike steers just fine, there's no trace of
binding or sticking, no matter how tight I try to make the jam nut.

The only problem is that the adjustment won't stay locked. Possibly
this is a hint that I'm not really jamming the nut, merely tightening
the jam nut until I can't hold the lower nut without a good wrench.

Would anybody hazard a guess how much jam torque is typically needed?
I'm probably not exceeding 15 ft-lbs. If customary practice calls for
much more, then I'm simply not jamming the nuts and may in fact have to
back off the lower one to get correct adjustment _and_ a secure jam.

Thanks to all for reading and replying!


I think you said 15ft/lb which seemed reasonable. The only
mfr spec I know is Tange at 200 in/lb or something past
16lbs. That's with two proper wrenches.

It's situational here. As other contributors have
mentioned, even slight thread damage (from riding with a
loose headset BTW) is a factor, steel locknut vs aluminum,
tall or not-so-tall locknut (some 1-1/8"x26t are quite thin)
and so on.
-
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

AMuzi wrote:

I think you said 15ft/lb which seemed reasonable. The only
mfr spec I know is Tange at 200 in/lb or something past
16lbs. That's with two proper wrenches.


16 ft-lbs doesn't seem especially tight.

I decided to re-try, using (highly im-)proper wrenches 8-)
More exactly, a pair of thin-ish water pump pliers and an
adjustable open-end. The pliers didn't mar the lower nut,
the steering feels ok. For now I'll just wait to see if
the nuts stay locked. There's a little headroom left to
make it tighter if that becomes necessary.

Thanks very much for reading and posting!

bob prohaska

On 5/3/2019 8:17 PM, bob prohaska wrote:
AMuzi wrote:

I think you said 15ft/lb which seemed reasonable. The only
mfr spec I know is Tange at 200 in/lb or something past
16lbs. That's with two proper wrenches.


16 ft-lbs doesn't seem especially tight.

I decided to re-try, using (highly im-)proper wrenches 8-)
More exactly, a pair of thin-ish water pump pliers and an
adjustable open-end. The pliers didn't mar the lower nut,
the steering feels ok. For now I'll just wait to see if
the nuts stay locked. There's a little headroom left to
make it tighter if that becomes necessary.

Thanks very much for reading and posting!


1-1/8 x 26t is a very fine thread for the application. Your
average guy could easily rip the threads right off the
column without breaking a sweat.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971