Headset loose three times

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sextoke1
Posts: 101
Joined: Sun Jan 22, 2017 19:45 pm

Headset loose three times

Postby sextoke1 » Sat Oct 12, 2019 11:26 am

Over the last year, the headset on Trek Emonda sl6 is loose. Bearing are all ok and in since new. After opening it this time, and cleaning out the upper bearing space, the bearing appears to fit in a lot more loose than other bikes. It has a od of 41.0mm and the diameter in the upper frame is 41.3mm. It may look like that after cycling for a while, the bearing might be rocking and pushing up the stem which in turn causes the loose headset. ...bearings are ok, insert in the steering tube looks ok, stem is torque correctly, there is also the correct amount of shim washers about the collet on the upper bearing and below the top cap. The main question is the Trek tolerance ok with 41.3mm ?


joey54321
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Joined: Sat Dec 12, 2009 22:00 pm

Re: Headset loose three times

Postby joey54321 » Mon Oct 14, 2019 11:28 am

Don't use any thread lock. Fix the issue rather than the symptoms.

That said, I am having a similar issue with my Focus CX bike.

Did the headset that is in the bike come supplied from Trek? Does this have their iso decoupler thing at the front? I'd contact Trek/the dealer you got it from regarding the tolerances.

Daniel B
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Joined: Wed Mar 08, 2006 12:43 pm

Re: Headset loose three times

Postby Daniel B » Mon Oct 14, 2019 11:44 am

Is the expander plug into the head tube torqued up correctly?
Assuming it is that kind of setup.

IIRC, the one on my CR1 loosened it self regularly, until I found a document recommending 8nm, which feels like a ton, but it did the job.
Felt F70 05 (Turbo)
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18

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The Rookie
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Re: Headset loose three times

Postby The Rookie » Mon Oct 14, 2019 14:23 pm

joey54321 wrote:Don't use any thread lock.

Thread lock and bearing lock have two different uses, if there is a tiny amount of play bearing lock is a very good solution.

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Ben6899
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Re: Headset loose three times

Postby Ben6899 » Mon Oct 14, 2019 15:19 pm

Is it an integrated headset? The bearings shouldn't need pressing in, but also they shouldn't be loose.

Check with Trek or an approved dealer/shop, but a 41.3mm seat for a 41.0mm bearing in a headset sounds about right to me. Based on experience from builds and popping bearings in and out for maintenance etc
Ben

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sextoke1
Posts: 101
Joined: Sun Jan 22, 2017 19:45 pm

Re: Headset loose three times

Postby sextoke1 » Mon Oct 14, 2019 20:50 pm

joey54321 wrote:Don't use any thread lock. Fix the issue rather than the symptoms.

That said, I am having a similar issue with my Focus CX bike.

Did the headset that is in the bike come supplied from Trek? Does this have their iso decoupler thing at the front? I'd contact Trek/the dealer you got it from regarding the tolerances.


First day bearings, no ISO decoupler, A standard head.

sextoke1
Posts: 101
Joined: Sun Jan 22, 2017 19:45 pm

Re: Headset loose three times

Postby sextoke1 » Mon Oct 14, 2019 20:53 pm

Daniel B wrote:Is the expander plug into the head tube torqued up correctly?
Assuming it is that kind of setup.

IIRC, the one on my CR1 loosened it self regularly, until I found a document recommending 8nm, which feels like a ton, but it did the job.


It felt ok, About a 2mm gap, I removed it, it looked nice and clean. Refitted and tighten it. I will remove it and check to 8Nm.

sextoke1
Posts: 101
Joined: Sun Jan 22, 2017 19:45 pm

Re: Headset loose three times

Postby sextoke1 » Mon Oct 14, 2019 20:58 pm

Ben6899 wrote:Is it an integrated headset? The bearings shouldn't need pressing in, but also they shouldn't be loose.

Check with Trek or an approved dealer/shop, but a 41.3mm seat for a 41.0mm bearing in a headset sounds about right to me. Based on experience from builds and popping bearings in and out for maintenance etc



Integrated headset. Yes bearing just drops in. I did not take much notice of the 41.3mm diameter of the top seat. The bearing felt looser than other heads. Looking closer at the seat. It looks like new and does not have worn due to misuse.
I will tighten the expander plug, spend more time on it and check it every few weeks.

sextoke1
Posts: 101
Joined: Sun Jan 22, 2017 19:45 pm

Re: Headset loose three times

Postby sextoke1 » Mon Oct 14, 2019 21:06 pm

The Rookie wrote:
joey54321 wrote:Don't use any thread lock.

Thread lock and bearing lock have two different uses, if there is a tiny amount of play bearing lock is a very good solution.



Loctite 641 would be ok for removal again. Fill gap is 0.1mm, but cures in the absence of air. Unsure how this would work as there would be plenty of air around it. Unsure would it damage the carbon fiber seating area.

david7m
Posts: 525
Joined: Wed May 23, 2018 08:26 am

Re: Headset loose three times

Postby david7m » Mon Oct 14, 2019 21:22 pm

I've a 2019 emonda and the headset has came loose once. Have you used the supplied torque wrench on the expander bolt first, then the stem bolts? Mine has been ok since.

Daniel B
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Joined: Wed Mar 08, 2006 12:43 pm

Re: Headset loose three times

Postby Daniel B » Mon Oct 14, 2019 21:24 pm

sextoke1 wrote:
Daniel B wrote:Is the expander plug into the head tube torqued up correctly?
Assuming it is that kind of setup.

IIRC, the one on my CR1 loosened it self regularly, until I found a document recommending 8nm, which feels like a ton, but it did the job.


It felt ok, About a 2mm gap, I removed it, it looked nice and clean. Refitted and tighten it. I will remove it and check to 8Nm.


Wo wo wo, the 8nm was specific to a Scott bike, might well be different with yours.
Maybe start low, and slowly increase the torque if you don't see the issue going away.
Felt F70 05 (Turbo)
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18

sextoke1
Posts: 101
Joined: Sun Jan 22, 2017 19:45 pm

Re: Headset loose three times

Postby sextoke1 » Mon Oct 14, 2019 21:39 pm

david7m wrote:I've a 2019 emonda and the headset has came loose once. Have you used the supplied torque wrench on the expander bolt first, then the stem bolts? Mine has been ok since.

No, if I could find out the torque setting that would be great.

david7m
Posts: 525
Joined: Wed May 23, 2018 08:26 am

Re: Headset loose three times

Postby david7m » Mon Oct 14, 2019 22:01 pm

sextoke1 wrote:
david7m wrote:I've a 2019 emonda and the headset has came loose once. Have you used the supplied torque wrench on the expander bolt first, then the stem bolts? Mine has been ok since.

No, if I could find out the torque setting that would be great.


Mine says "5.2nm max" between the bolts, and the supplied torque wrench is 5nm.

david7m
Posts: 525
Joined: Wed May 23, 2018 08:26 am

Re: Headset loose three times

Postby david7m » Mon Oct 14, 2019 22:03 pm

As Daniel B said, going to 8nm is a big jump!


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