Is this a dangerous upgrade?

Discuss light weight issues concerning road bikes & parts.
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zalle
Posts: 70
Joined: Sun Sep 25, 2016 11:14 pm

by zalle

Hi guys, I've been advised here to exchange the stock headset expander for a very light one.

I took the fork to my mechanic for him to replace it and he said not to do it. He says bikes with spacers under the stem should use long headset expanders. Using small ones may not be strong enough causing the carbon fork to brake

What do you think?

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Juanmoretime
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by Juanmoretime

I'm not sure I agree with that. Some forks are designed to require the support from the expander but the area for support is generally where the stem clamps to the fork and no lower. Also most forks are only designed to handle 50mm stack of spacers since are can add an area of stress at the headset. Many modern forks don't even need an expander after the headset is set. Set it and remove.
RESIDENT GRUMPY OLD MAN.

by Weenie


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Kayrehn
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Joined: Thu Mar 24, 2011 6:06 pm

by Kayrehn

Read most of the past threads on this topic and the collective wisdom of the members here generally concurs that it'll be fine to do without the expander plug.

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ms6073
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Location: Houston, Texas

by ms6073

To add to the discussion, Enve's compression plug is relatively short compared to other non-oem solutions.
Michael - The Anaerobic Threshold is neither...

kode54
Posts: 1128
Joined: Tue May 23, 2006 9:39 pm

by kode54

Juanmoretime wrote:I'm not sure I agree with that. Some forks are designed to require the support from the expander but the area for support is generally where the stem clamps to the fork and no lower. Also most forks are only designed to handle 50mm stack of spacers since are can add an area of stress at the headset. Many modern forks don't even need an expander after the headset is set. Set it and remove.


agreed. where the stem clamps onto the steerer is where the most compression will occur. i've been using a light expander on all my bikes. i have an Extralite in one and the other two, i have the EE Cycleworks top nut.
- AX Lightness Vial EVO D + DA9150 + Enve SES 3.4 carbon hubs
- Parlee Altum + DA9150 + Enve SES 4.5 carbon hubs
- Parlee ESX + DA9150 + THM SRM PM + Enve SES 6.7 CK hubs
- Independent Fabrication Ti FLW + DA9100 + Enve 3.4 CK hubs

Svetty
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Location: Yorkshire - God's Own Country

by Svetty

The steerer isn't supported internally where it contacts the inner races of the headset bearings and this is where road impacts are transmitted through to the frame. The use of a bung to protect against the steerer being crushed by the stem is more to protect against inadvertent over-tightening than anything IMO - the steerer should be strong enough to support normal stem compression. if it is marginal at this point I would not feel confident hitting potholes at speed!

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Kayrehn
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Joined: Thu Mar 24, 2011 6:06 pm

by Kayrehn

The extralite ultrastar expander, a favourite amongst many here and one that I've used for 5 years, is merely a cm thick and certainly can't protect the steerer tube from being crushed given the height of the stem, if that was a necessary function.

Delorre
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Joined: Sat May 24, 2014 12:09 pm

by Delorre

95% of the Canyons of the past years have been deliverd without any compression plug (Accross I70 headset instead). The have 1"1/4 headsets, OK, so maybe a little stonger than the regular 1 1/8 on most bikes, but I wouldn't worry to much riding without one. And absolutely not if you use an Extralite instead of the stock one.

nickf
Posts: 549
Joined: Sat Mar 06, 2010 10:34 pm

by nickf

Been using a extralite for 3-4 years now on cannondale and trek full carbon forks with no issues. They don't slip and weight close to nothing.

zalle
Posts: 70
Joined: Sun Sep 25, 2016 11:14 pm

by zalle

Well, I got a J&L superlight expander. So this is safe for my Roubaix carbon fork? It looks exactly the same as the extralite one.

How deep shall I put it inside the fork? About 1cm? Thanks.

pdlpsher1
Posts: 1434
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

Look at this way. Why do you think your bike came with a long and heavy expander? If they could save weight by using a smaller expanded why wouldn't they have done it? Why not call the manufacturer and ask them if it's ok? After they engineered the bike.


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AJS914
Posts: 1903
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

I tried the J&L and found it didn't fit my Colnago and went back to an FSA.

mattr
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Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Don't think many companies actually make an expander long enough to cover the height of the spacer stack allowed for in the manual/instructions. (maximum of around 60-70 mm of steerer exposed from the top bearing, give or take)
At least, not long enough to *realistically* add any support whatsoever. (would need to be a very tight fit along the entire length, and about 100 mm long.)

If the steerer needed to be supported, they'd just make it thicker. Or provide a glued insert as you have on those steerers that need support from the compressive hoop stresses and so on from the stem clamp, so generally they have a bonded in tube, to ensure it's in the right place, doesn't move and isn't easy for tinkerers to remove to reduce weight. They don't thicken the steerer, or they'd have to make about 15 versions to cover all the different length head tubes........

TL:DR If there isn't a bonded in insert, it's almost certainly ok. As long as you don't fit your stem with an impact driver.

by Weenie


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