Integrated headset problem? repost#2 w/ pic & question



K

kwalters

Guest
Can't believe I did that. Orginally posted question ~2 wks
ago but w/o pic. The question is:

Is there a problem with this integrated headset bearing seat?

and the pic is here:

http://photobucket.com/albums/a158/kwalters1532/

one pic shows top profile of headtube (FWIW).

2nd pic is top bearing seat (note 1/2mm dim. is closer to 3/4mm).
Dark, concentric, varying-width inner ring is the machined seat
OEM-chamfered to ~45 degrees. Cane Creek IS headset. Bottom seat
is comparable but not as pronounced. Click pic to larger-than-life.

Frame is 2004 Trek/Lemond Victorie Classic road ti 1-1/8 with bearing
seats machined into headtube top & bottom. Approx 7000 miles.

Have read C. King's paper on integrated headsets.

Any comments would be greatly appreciated.

Thanks. Ken (kwalters <at> frii <dot> com)
 
kwalters wrote:
>
> Is there a problem with this integrated headset bearing seat?
>
> http://photobucket.com/albums/a158/kwalters1532/


There is probably nothing "wrong" (that is, out of spec) with your
frame. The eccentricity between the head tube top bore and the tube's
outside diameter is more than likely the result of the reamer going in
more or less precisely in the intended location when the frame's head
tube was just a little off. I have both seen and owned bikes that
exhibited similar misalignments but had no related functional problems.


Chalo Colina
 
On 23 Oct 2005 01:44:10 -0700, "Chalo" <[email protected]> wrote:

>kwalters wrote:
>>
>> Is there a problem with this integrated headset bearing seat?
>>
>> http://photobucket.com/albums/a158/kwalters1532/

>
>There is probably nothing "wrong" (that is, out of spec) with your
>frame. The eccentricity between the head tube top bore and the tube's
>outside diameter is more than likely the result of the reamer going in
>more or less precisely in the intended location when the frame's head
>tube was just a little off. I have both seen and owned bikes that
>exhibited similar misalignments but had no related functional problems.


Agreement here; though I dislike the whole integrated headset idea for
a variety of reasons, the head tube should be more than strong enough
to operate without failure given the available wall thickness at the
thinnest point. Absent a geometry problem, I would have no qualms
about calling this issue purely cosmetic.
--
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Posted 2 more pics showing bearing seat from 2 angles:

"normalbearingseat" is @ the 2mm wall thickness.
top of seat is ~4.5mm below top of headtube; bottom of chamfer
is ~5.5mm below top of headtube.

"areainquestion" is @ the 3/4mm wall thickness.
top of seat is ~ 4.5mm below top of ht; but bottom of
chamfer is ~7mm below top of ht.

Can this be attributed to non-concentric milling, or bearing
wear? Should there be a bearing alignment issue?
Ken

kwalters wrote:
> Can't believe I did that. Orginally posted question ~2 wks
> ago but w/o pic. The question is:
>
> Is there a problem with this integrated headset bearing seat?
>
> and the pic is here:
>
> http://photobucket.com/albums/a158/kwalters1532/
>
> one pic shows top profile of headtube (FWIW).
>
> 2nd pic is top bearing seat (note 1/2mm dim. is closer to 3/4mm).
> Dark, concentric, varying-width inner ring is the machined seat
> OEM-chamfered to ~45 degrees. Cane Creek IS headset. Bottom seat
> is comparable but not as pronounced. Click pic to larger-than-life.
>
> Frame is 2004 Trek/Lemond Victorie Classic road ti 1-1/8 with bearing
> seats machined into headtube top & bottom. Approx 7000 miles.
>
> Have read C. King's paper on integrated headsets.
>
> Any comments would be greatly appreciated.
>
> Thanks. Ken (kwalters <at> frii <dot> com)
>