Adjusting headset preload

[Jeff]

....still new to threadless headsets and forks. ...about to install a carbon
fiber fork with CF steerer tube (1.125") on a frame with a King headset
installed.

I've seen different instructions. Some speak about looking for looseness in
the fork after adjusting the preload, others speak about torquing the
headset cap bolt to a certain amount prior to clamping the stem, others
about turning the bolt a certain number of turns after the cap contacts the
stem or spacers above the stem.

Is there any consensus about how tight to have one of these systems?

By the way, is there any reason other than cosmetics to reduce the steerer
tube height from my current 25mm above the stem (with corresponding spacers)
to a shorter amount? Other than looks, I see no real mechanical reason why
this amount would make anything weaker in any way. Most instructions say
that 40mm is the max for a 1.125" steerer.

Jeff


--
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[sally]

"Jeff" <[email protected]> wrote in
news:[email protected]:
> I've seen different instructions. Some speak about looking for looseness
> in the fork after adjusting the preload, others speak about torquing the
> headset cap bolt to a certain amount prior to clamping the stem, others
> about turning the bolt a certain number of turns after the cap contacts
> the stem or spacers above the stem.

Try www.parktool.com

> By the way, is there any reason other than cosmetics to reduce the
> steerer tube height from my current 25mm above the stem (with
> corresponding spacers) to a shorter amount? Other than looks, I see no
> real mechanical reason why this amount would make anything weaker in any
> way. Most instructions say that 40mm is the max for a 1.125" steerer.

A big stack of spacers above the stem is weaker because the compression plug
is not inside the stem. This more a problem with carbon steering tubes than
with metal.

 

[Nate Knutson]

On Oct 8, 9:31 pm, "Jeff" <[email protected]> wrote:
> ...still new to threadless headsets and forks. ...about to install a carbon
> fiber fork with CF steerer tube (1.125") on a frame with a King headset
> installed.
>
> I've seen different instructions. Some speak about looking for looseness in
> the fork after adjusting the preload, others speak about torquing the
> headset cap bolt to a certain amount prior to clamping the stem, others
> about turning the bolt a certain number of turns after the cap contacts the
> stem or spacers above the stem.
>
> Is there any consensus about how tight to have one of these systems?

As loose as possible with zero play - there's probably about as much
consensus on that as any bike-related topic you'll find.

Using torque or counting rotations on the top cap are really only
close to useful for explaining the basic idea of how to do it - in
practice neither are really precise enough and are only able to
usually get you in the ballpark. After you make an initial adjustment,
you should indeed check for play or tightness, ideally using some
different methods. It's best technically to start with a conservative
(somewhat likely to be looser than needed) adjustment and work from
there; eventually you'll get a feel and be faster. Also, you don't
need to fully secure your stem bolts until you've tested the
adjustment. Here are the steps I go through:
Forcefully rock fork/bars back and fourth with the front end off the
ground and frame held in a way where play can be felt.
In non-suspended bikes, lift front end off the ground and drop it from
a few inches, which can show looseness via a characteristic rattle.
With both wheels on the ground, turn the fork/bars 90 degrees and
firmly jerk the bike forward via the frame, which will let you feel
play in the headset. You can sometimes accomplish the same thing by
locking the front brake, and some people always do this, but it's
often difficult to confidently tell brake pivot play apart from hs
play.
Lift the whole bike up without holding the fork/bars, and with the
front end pointed down, slowly move the rest of the bike laterally
back and fourth. This lets you see how freely the front end is moving.
It generally should move very freely on a well-adjusted hs.

 

[Qui si parla Campagnolo-www.vecchios.com]

On Oct 8, 10:31 pm, "Jeff" <[email protected]> wrote:
> ...still new to threadless headsets and forks. ...about to install a carbon
> fiber fork with CF steerer tube (1.125") on a frame with a King headset
> installed.
>
> I've seen different instructions. Some speak about looking for looseness in
> the fork after adjusting the preload, others speak about torquing the
> headset cap bolt to a certain amount prior to clamping the stem, others
> about turning the bolt a certain number of turns after the cap contacts the
> stem or spacers above the stem.
>
> Is there any consensus about how tight to have one of these systems?
>
> By the way, is there any reason other than cosmetics to reduce the steerer
> tube height from my current 25mm above the stem (with corresponding spacers)
> to a shorter amount? Other than looks, I see no real mechanical reason why
> this amount would make anything weaker in any way. Most instructions say
> that 40mm is the max for a 1.125" steerer.
>
> Jeff
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com

Max for most forks is 40mm under the stem..and 5mm above recommended
so all the stem clamps a portion of the steerer but having some above
does give you some flexibility in sizing until you are sure..then can
cut. Always easier to make the steerer shorter.

 

[jim beam]

Jeff wrote:
>
> ...still new to threadless headsets and forks. ...about to install a
> carbon fiber fork with CF steerer tube (1.125") on a frame with a King
> headset installed.
>
> I've seen different instructions. Some speak about looking for looseness
> in the fork after adjusting the preload, others speak about torquing the
> headset cap bolt to a certain amount prior to clamping the stem, others
> about turning the bolt a certain number of turns after the cap contacts
> the stem or spacers above the stem.
>
> Is there any consensus about how tight to have one of these systems?

what works for me is to use the long leg of the allen wrench in the
tightening bolt and use finger tight on the short leg. that prevents
too much torque, but allows you to get it tight enough. i've never seen
a manufacturer spec for this procedure.


>
> By the way, is there any reason other than cosmetics to reduce the
> steerer tube height from my current 25mm above the stem (with
> corresponding spacers) to a shorter amount? Other than looks, I see no
> real mechanical reason why this amount would make anything weaker in any
> way. Most instructions say that 40mm is the max for a 1.125" steerer.
>
> Jeff
>
>

there is a limit to how many below [leverage], but not above [no
leverage] - simply cosmetics.

 

[Jeff]

"Qui si parla Campagnolo-www.vecchios.com" <[email protected]> wrote in
message news:[email protected]...

> Max for most forks is 40mm under the stem..and 5mm above recommended
> so all the stem clamps a portion of the steerer but having some above
> does give you some flexibility in sizing until you are sure..then can
> cut.

I've seen the 40mm listed as 40mm total and 40mm below. I've also seen the
recommendation of 5mm max above, but also no limit above. I've also seen it
listed as 5mm minimum.

I can't understand what difference the length above would have other than
placing the expander within the stem for extra strength as another person
already mentioned and the fact that you would want a spacer above to keep
the steerer within the stem.

You are suggesting 5mm above as a minimum correct? (and not a maximum)

Jeff




--
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[[email protected]]

On Oct 9, 8:14 am, "Jeff" <[email protected]> wrote:
> "Qui si parla Campagnolo-www.vecchios.com" <[email protected]> wrote in
> messagenews:[email protected]...
>
> > Max for most forks is 40mm under the stem..and 5mm above recommended
> > so all the stem clamps a portion of the steerer but having some above
> > does give you some flexibility in sizing until you are sure..then can
> > cut.
>
> I've seen the 40mm listed as 40mm total and 40mm below. I've also seen the
> recommendation of 5mm max above, but also no limit above. I've also seen it
> listed as 5mm minimum.
>
> I can't understand what difference the length above would have other than
> placing the expander within the stem for extra strength as another person
> already mentioned and the fact that you would want a spacer above to keep
> the steerer within the stem.
>
> You are suggesting 5mm above as a minimum correct? (and not a maximum)
>
> Jeff
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com

The 5mm above minimum for a carbon steerer would be to not wanting the
fragile edge of the carbon steerer being clamped by the stem. More
strength in the steerer if you are compressing the whole circumference
and not clamping on the open end of the carbon steerer. Probably not
a huge difference in strength, but it does not hurt to have a bit of
extra insurance for free.

 

[Lou Holtman]

Jeff wrote:
>
> ...still new to threadless headsets and forks. ...about to install a
> carbon fiber fork with CF steerer tube (1.125") on a frame with a King
> headset installed.
>
> I've seen different instructions. Some speak about looking for looseness
> in the fork after adjusting the preload, others speak about torquing the
> headset cap bolt to a certain amount prior to clamping the stem, others
> about turning the bolt a certain number of turns after the cap contacts
> the stem or spacers above the stem.
>
> Is there any consensus about how tight to have one of these systems?
>
> By the way, is there any reason other than cosmetics to reduce the
> steerer tube height from my current 25mm above the stem (with
> corresponding spacers) to a shorter amount? Other than looks, I see no
> real mechanical reason why this amount would make anything weaker in any
> way. Most instructions say that 40mm is the max for a 1.125" steerer.
>
> Jeff
>

Jeff, get the damn thing in your frame.. ;-) It takes an averaged person
about half an hour. You worry to much.
Adjusting a threadless headset is the same as a threaded one: begin at
the loose side and after adjusting look for looseness by rocking the
bike back and forth or dropping it from a few inches and listen if it
rattles. My experience is that a King headset is quite forgiving.
A 5 mm spacer above the stem doesn't hurt (I think it doesn't make much
of a difference with a decent expansion plug) and use a torque wrench
and a decent stem.

Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)

 

[Jeff]

"Lou Holtman" <[email protected]> wrote in message
news:[email protected]...

> Jeff, get the damn thing in your frame.. ;-) It takes an averaged person
> about half an hour. You worry to much.
> Adjusting a threadless headset is the same as a threaded one: begin at the
> loose side and after adjusting look for looseness by rocking the bike back
> and forth or dropping it from a few inches and listen if it rattles. My
> experience is that a King headset is quite forgiving.
> A 5 mm spacer above the stem doesn't hurt (I think it doesn't make much of
> a difference with a decent expansion plug) and use a torque wrench and a
> decent stem.
>
> Lou


Thanks Lou (and others) - I would normally agree with you about just doing
it and being able to alter things later.

....but since I'm still waiting on a few parts (...should be here by the end
of the week), I still have some time to ask a few advanced questions. So far
I only have the derailleurs and brakes installed and was messing with the
fork/headset a bit yesterday. ...need the campy BB wrench I ordered to
finish installing the crank and still need the handlebars to actually get
the cables on. Since I've only built up about 4 bikes in the past, I'm still
a bit nervous about working with components that ran me several times my
monthy mortgage. If all goes well, I should have this up and riding by the
weekend.




--
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[Jeff]

"Lou Holtman" <[email protected]> wrote in message
news:[email protected]...

> Jeff, get the damn thing in your frame.. ;-) It takes an averaged person
> about half an hour. You worry to much.
> Adjusting a threadless headset is the same as a threaded one: begin at the
> loose side and after adjusting look for looseness by rocking the bike back
> and forth or dropping it from a few inches and listen if it rattles. My
> experience is that a King headset is quite forgiving.
> A 5 mm spacer above the stem doesn't hurt (I think it doesn't make much of
> a difference with a decent expansion plug) and use a torque wrench and a
> decent stem.
>
> Lou


Thanks Lou (and others) - I would normally agree with you about just doing
it and being able to alter things later.

....but since I'm still waiting on a few parts (...should be here by the end
of the week), I still have some time to ask a few advanced questions. So far
I only have the derailleurs and brakes installed and was messing with the
fork/headset a bit yesterday. ...need the campy BB wrench I ordered to
finish installing the crank and still need the handlebars to actually get
the cables on. Since I've only built up about 4 bikes in the past, I'm still
a bit nervous about working with components that ran me several times my
monthy mortgage. If all goes well, I should have this up and riding by the
weekend.




--
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[Jambo]

"jim beam" <[email protected]> wrote in message
news:[email protected]...

> what works for me is to use the long leg of the allen wrench in the
> tightening bolt and use finger tight on the short leg. that prevents too
> much torque, but allows you to get it tight enough.

So how do you know it's not "too much"? Idiot.

> there is a limit to how many below [leverage], but not above [no
> leverage] - simply cosmetics.

********.