minimum spacers under stem?

John Forrest Tomlinson said:

Does anyone have any thoughts about this minimum? I was thinking of
using a setup with no spacers under the stem on an aluminum steerer
tube.

Each of these guys, with integrated headsets, have no extra spacers (I didn't
filter for Al steerer tube):
http://www.cyclingnews.com/photos/2007/tech/probikes/?id=liquigas_cannondale_luca_paolini/Luca_Paolini_Liquigas_Cannondale_System_Six_front_end
http://www.cyclingnews.com/photos/2007/tech/probikes/?id=quickstep_specialized_boonen/Boonen1683
http://www.cyclingnews.com/photos/2007/tech/probikes/?id=tmobile_giant_linus_gerdemann/24
http://www.cyclingnews.com/photos/2007/tech/probikes/?id=/photos/2007/tech/probikes/jj_haedo_cervelo07/JJ_Haedo_Team_CSC_Cervelo_Soloist_Carbon_controls
http://www.cyclingnews.com/photos/2006/tech/probikes/?id=/photos/2006/tech/probikes/colavita_felt_f1c_mccormack/DSCN1027
http://www.cyclingnews.com/photos/2006/tech/probikes/?id=kgsn_bjm_merckx/BJM_KGSN_front_end

Basso, with an external headset has a spacer:
http://www.cyclingnews.com/photos/2007/tech/probikes/?id=ivan_basso_trek07/Ivan_Basso_Discovery_Channel_Trek_Madone_SSL_69_head_tube

But with the same headset:
http://www.cyclingnews.com/photos/2006/tech/probikes/?id=colnagoc50/ColnagoCross7

On Mar 8, 6:33 am, John Forrest Tomlinson <[email hidden]>

Quoted message said:

Fromhttp://www.velonews.com/tech/report/articles/11432.0.html

according to Trek:

Quoted message said:

The number and placement of spacers does have an effect on
the fatigue life of an aluminum steerer tube. Running less than 5mm of
spacers under the stem can concentrate or "point load" a great deal of
stress in one spot on the steerer. Therefore, Bontrager recommends
a minimum of 5mm, and a maximum of 40mm of spacers between the
stem and the headset to maximize the fatigue life of the steerer.

Does anyone have any thoughts about this minimum? I was thinking of
using a setup with no spacers under the stem on an aluminum steerer
tube.
--
JT
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I would put a 5mm under the stem. It is only about 1/6 inch.

On Mar 8, 10:44 am, "Qui si parla Campagnolo" <[email hidden]>

Quoted message said:

On Mar 8, 6:33 am, John Forrest Tomlinson <[email hidden]>

Quoted message said:

Fromhttp://www.velonews.com/tech/report/articles/11432.0.html

Quoted message said:

according to Trek:

Quoted message said:

Quoted message said:

The number and placement of spacers does have an effect on
the fatigue life of an aluminum steerer tube. Running less than 5mm of
spacers under the stem can concentrate or "point load" a great deal of
stress in one spot on the steerer. Therefore, Bontrager recommends
a minimum of 5mm, and a maximum of 40mm of spacers between the
stem and the headset to maximize the fatigue life of the steerer.

Quoted message said:

Does anyone have any thoughts about this minimum? I was thinking of
using a setup with no spacers under the stem on an aluminum steerer
tube.
--
JT
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I would put a 5mm under the stem. It is only about 1/6 inch.- Hide quoted text -

- Show quoted text -

I've used steel, aluminum, and carbon steerers with no spacers under
the stem (on road bikes) for long periods and never had an issue.
None of these were Trek products, though, and I suppose they
demonstrated at Paris-Roubaix last year that we should take warnings
regarding their steerers seriously.

Thanks guys.

Qui si parla Campagnolo said:

I would put a 5mm under the stem. It is only about 1/6 inch.

Peter, any thoughts on why? Or is it just, "why not?"
--
JT
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On Mar 8, 10:44 am, "Qui si parla Campagnolo" <[email hidden]>

Quoted message said:

I would put a 5mm under the stem. It is only about 1/6 inch.

Do you figure the TTC on a Hiddenset counts as a spacer? That's all I
have ever had between my stem and the headset. I wanted to go a bit
lower but the cost of the ordinary top cap, alone, was around $50 or
so.

--
Mike (Xyzzy)

On Mar 8, 4:20 pm, John Forrest Tomlinson <[email hidden]>

Quoted message said:

Thanks guys.

Qui si parla Campagnolo said:

I would put a 5mm under the stem. It is only about 1/6 inch.

Peter, any thoughts on why? Or is it just, "why not?"
--
JT
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I don't like to have stems against headset top caps...just never have
done it, no real reason. A wee spacer doesn't hurt anything.

Qui si parla Campagnolo said:

On Mar 8, 4:20 pm, John Forrest Tomlinson <[email hidden]>

Quoted message said:

Thanks guys.

Qui si parla Campagnolo said:

I would put a 5mm under the stem. It is only about 1/6 inch.

Peter, any thoughts on why? Or is it just, "why not?"

I don't like to have stems against headset top caps...just never have
done it, no real reason. A wee spacer doesn't hurt anything.

Just speculating, would a spacer keep an incorrectly faced head tube
from bending the stem when the front wheel is turned?

I'm thinking perhaps the spacer would leave a gap on the low part of the
stem/head tube joint, while bearing against the high part of the gap. A
stem installed without the spacer might be installed flush against the
head tube, resulting in some tension and bending when the steerer is
rotated.

Pat