# Trek top cap max torque... really ?



## ToiletSiphon (Jul 23, 2014)

So I just got a brand new Trek Emonda ALR Disc 5. I realized that the top cap screw has a "4nm max torque" written on it. 

Is it me or is this figure a good way to have a bunch of people ruin their headset bearings? By tightening by my usual rule of thumb (no play + 1/2 turn), I end up around 2.5 to 2.8 nM. 4nM does seems excessive.


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## cxwrench (Nov 9, 2004)

Since they can't laser etch complete headset adjustment instructions on a top cap I guess they just figured a MAX value would be good enough for most people. Not all people mind you, but most. You can take that for what it's worth, or you can overthink it...


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## Srode (Aug 19, 2012)

ToiletSiphon said:


> So I just got a brand new Trek Emonda ALR Disc 5. I realized that the top cap screw has a "4nm max torque" written on it.
> 
> Is it me or is this figure a good way to have a bunch of people ruin their headset bearings? By tightening by my usual rule of thumb (no play + 1/2 turn), I end up around 2.5 to 2.8 nM. 4nM does seems excessive.


No different than max pressure written on the sidewalls of tires. It's not a torque spec, its the max.


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## Jay Strongbow (May 8, 2010)

ToiletSiphon said:


> So I just got a brand new Trek Emonda ALR Disc 5. I realized that *the top cap screw* has a "4nm max torque" written on it.
> 
> Is it me or is this figure a good way to have a bunch of people ruin their headset bearings? By tightening by my usual rule of thumb (no play + 1/2 turn), I end up around 2.5 to 2.8 nM. 4nM does seems excessive.


I was just about to say I'd need to see it to believe it but I looked at one of my top cap screws and it does have some writing there too. Don't have a magnifying glass so don't know what it says though.

Anyway, sure, I can see some people getting misled by that.


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## tlg (May 11, 2011)

Srode said:


> It's not a torque spec, its the max.


BINGO

Just because you 'can' doesn't mean you need to or should. What they're saying is if you get to 4nm and your headset isn't tight... something is wrong. Don't keep tightening.


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## ToiletSiphon (Jul 23, 2014)

tlg said:


> BINGO
> 
> Just because you 'can' doesn't mean you need to or should. What they're saying is if you get to 4nm and your headset isn't tight... something is wrong. Don't keep tightening.


The thing I forgot to mention is when the saleseman installed me the new stem, he pulled out the torque wrench, set it to 4nM and tightened the cap without thinking. I'm not confrontational so I just said WTF in my head and just re-tightened everything properly back home. 

Envoyé de mon SM-A530W en utilisant Tapatalk


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## cxwrench (Nov 9, 2004)

ToiletSiphon said:


> The thing I forgot to mention is when the saleseman installed me the new stem, he pulled out the torque wrench, set it to 4nM and tightened the cap without thinking. I'm not confrontational so I just said WTF in my head and just re-tightened everything properly back home.
> 
> Envoyé de mon SM-A530W en utilisant Tapatalk


That is wrong unless you have a Domane w/ front Iso Speed. That is the ONLY time you'd actually want to tighten a top cap to 4nm as there is a wave washer under the upper headset bearing. You are correct that is usually less than 3nm to get proper bearing preload on a headset.


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## ToiletSiphon (Jul 23, 2014)

cxwrench said:


> That is wrong unless you have a Domane w/ front Iso Speed. That is the ONLY time you'd actually want to tighten a top cap to 4nm as there is a wave washer under the upper headset bearing. You are correct that is usually less than 3nm to get proper bearing preload on a headset.


Didn't know why trek advised this for the Domane, I'll wake up smarter tomorrow.

But I have an Emonda alr. Maybe the guy just developed a bad habit setting up too many Domanes

Envoyé de mon SM-A530W en utilisant Tapatalk


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## cxwrench (Nov 9, 2004)

ToiletSiphon said:


> Didn't know why trek advised this for the Domane, I'll wake up smarter tomorrow.
> 
> But I have an Emonda alr. Maybe the guy just developed a bad habit setting up too many Domanes
> 
> Envoyé de mon SM-A530W en utilisant Tapatalk


Read my post again. There's a wave washer under the upper bearing on the SL and SLR. You need 4nm to properly compress the wave washer.


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## sasquatch16 (Feb 7, 2013)

cxwrench said:


> That is wrong unless you have a Domane w/ front Iso Speed. That is the ONLY time you'd actually want to tighten a top cap to 4nm as there is a wave washer under the upper headset bearing. You are correct that is usually less than 3nm to get proper bearing preload on a headset.


Great information. I have a Domane SLR and have been tightening top cap just enough to remove play. Definitely not 4nm. Will have to get a 4nm wrench.
thanks


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## ToiletSiphon (Jul 23, 2014)

cxwrench said:


> Read my post again. There's a wave washer under the upper bearing on the SL and SLR. You need 4nm to properly compress the wave washer.


I understood your post, just said I didn't know prior to reading it. 

Envoyé de mon SM-A530W en utilisant Tapatalk


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## C-40 (Feb 4, 2004)

It's actually difficult to damage a modern angular contact cartridge headset bearing. If you tighten the top cap too much, the front wheel won't automatically return to a straight ahead position, after a turn. You'll notice that real quick. As long as that doesn't happen, the bearings won't be damaged.

Traditional headsets are a different story. It takes a delicate touch to get no slop but no drag on those bearings and only a slight torque on the top cap can cause lots of drag and a major problem.


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## Methodical (Jul 21, 2012)

ToiletSiphon said:


> So I just got a brand new Trek Emonda ALR Disc 5. I realized that the top cap screw has a "4nm max torque" written on it.
> 
> Is it me or is this figure a good way to have a bunch of people ruin their headset bearings? By tightening by my usual rule of thumb (no play + 1/2 turn), I end up around 2.5 to 2.8 nM. 4nM does seems excessive.


I had the same question when I was building my Emonda. I thought that was way too much as I usually set it to whatever keeps it from being loose and making noise. I contacted Trek and was told that rating is for the expander plug and not the actual top cap bolt. If that is truly true, then it's very misleading. Hell, once it's all set up you can actually remove the top cap and it won't affect the set up.


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## cxwrench (Nov 9, 2004)

Methodical said:


> I had the same question when I was building my Emonda. I thought that was way too much as I usually set it to whatever keeps it from being loose and making noise. I contacted Trek and was told that rating is for the expander plug and not the actual top cap bolt. If that is truly true, then it's very misleading. Hell, once it's all set up you can actually remove the top cap and it won't affect the set up.


Whomever you talked to at Trek was wrong...the torque for the expander is much higher than 4nm, it's actually more than double. Says so right on it. 9-10nm.

4nm is the MAX...that doesn't mean you ever need to get it that tight anymore than a 120psi MAX pressure means you ever need to actually inflate your tire to that pressure.


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## Methodical (Jul 21, 2012)

cxwrench said:


> Whomever you talked to at Trek was wrong...the torque for the expander is much higher than 4nm, it's actually more than double. Says so right on it. 9-10nm.
> 
> 4nm is the MAX...that doesn't mean you ever need to get it that tight anymore than a 120psi MAX pressure means you ever need to actually inflate your tire to that pressure.


I fully understand what those torque ratings around the bike mean and I am not questioning that. I was just unsure whether the torque spec on the cap applied to the cap, the expander plug or both, since the expander plug nor the booklet that came with the frame had torque specifications for the expander plug.

I did some checking online and all I could find were build manuals for the Domane and Madone, no luck with the Emonda. I found some videos where the person stated that if there were no torque specs to go with 5nm as a general rule. That's when I called Trek and was told what I was told.

Do you have documentation that specifically states that the torque setting for the Emonda expander plug is 9-10nm because I have not been able to find any information online and Trek says it's only 4nm? I'd appreciate it. Thanks


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## Jay Strongbow (May 8, 2010)

Methodical said:


> I had the same question when I was building my Emonda. I thought that was way too much as I usually set it to whatever keeps it from being loose and making noise. I contacted Trek and was told that rating is for the expander plug and not the actual top cap bolt. If that is truly true, then it's very misleading. Hell, once it's all set up you can actually remove the top cap and it won't affect the set up.


I'm guessing 'for the expander plug' is correct but you misunderstood what that meant or he did a poor job of explaining.

I'd have to imagine 'for the expander plug" means the expander plug won't hold if you put 4nm of pull on it with the top cap screw. Not that the expander plug needs 4nm for installation.


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## Methodical (Jul 21, 2012)

Jay Strongbow said:


> I'm guessing 'for the expander plug' is correct but you misunderstood what that meant or he did a poor job of explaining.
> 
> I'd have to imagine 'for the expander plug" means the expander plug won't hold if you put 4nm of pull on it with the top cap screw. Not that the expander plug needs 4nm for installation.


No miscommunication or understanding on my part. I was very clear with my questions to Trek and that is what I was told. To be sure what I was told, I always repeat back to the rep what was stated to make sure I understood exactly what was stated. Maybe the rep was wrong, he did have to ask someone, so who knows.

I torqued the expander plug to 4nm as Trek suggested without issues. And as always, I just tighten the cap to the point where there's no movement at the fork.


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## cxwrench (Nov 9, 2004)

Methodical said:


> No miscommunication or understanding on my part. I was very clear with my questions to Trek and that is what I was told. To be sure what I was told, I always repeat back to the rep what was stated to make sure I understood exactly what was stated. Maybe the rep was wrong, he did have to ask someone, so who knows.
> 
> I torqued the expander plug to 4nm as Trek suggested without issues. And as always, I just tighten the cap to the point where there's no movement at the fork.



The expander will most likely pull out of the fork if you only tighten it to 4nm. Generally the top part of the expander will be laser etched w/ the torque range, the ones Trek use (as I posted previously) are supposed to be tightened to 9-10nm. Here's the one on my Crockett...


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## Methodical (Jul 21, 2012)

cxwrench said:


> The expander will most likely pull out of the fork if you only tighten it to 4nm. Generally the top part of the expander will be laser etched w/ the torque range, the ones Trek use (as I posted previously) are supposed to be tightened to 9-10nm. Here's the one on my Crockett...


Man, I wish it were stamped on mine like that. When I was assembling the bike, I looked all over that plug and nothing. That's why I called Trek. I will take the cap off and look one more time, but I'm not hopeful though. Thanks...


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## ogre (Dec 16, 2005)

Just noticed today that the top cap on my Fuel EX8+ also says 4Nm max torque.


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## [email protected] (Jan 7, 2019)

4Nm is what I always suggest using, but you can bring it under if you have it tight where there is no play in the headset or spacers.


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## Methodical (Jul 21, 2012)

CX, here's the photo of the top of the expander plug on my Emonda. Unlike yours, Trek doesn't provide any torque specifications for the expander plug. I searched around the web and found nothing on it.









Not sure why the image did not post in my response as a thumbnail.


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## cxwrench (Nov 9, 2004)

Methodical said:


> CX, here's the photo of the top of the expander plug on my Emonda. Unlike yours, Trek doesn't provide any torque specifications for the expander plug. I searched around the web and found nothing on it.
> 
> View attachment 325671
> 
> ...


Interesting. I'm sure I've seen them like yours but just never really noticed because I've seen so many w/ the torque spec on them and just know how tight to make them. That's definitely a part that should have the spec in a visible spot.


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## Methodical (Jul 21, 2012)

cxwrench said:


> Interesting. I'm sure I've seen them like yours but just never really noticed because I've seen so many w/ the torque spec on them and just know how tight to make them. That's definitely a part that should have the spec in a visible spot.


Yeah, that's what I thought, too. Hopefully, Mitch will come back and clear the air on this. Below is the video where the guy said to use 5nm if there were no torque specs for the plug (see 1:38). That's why I just called Trek because I kept reading horror stories about this part needing to be done correctly.

https://www.youtube.com/watch?v=aBjJ35B-Og0


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## cxwrench (Nov 9, 2004)

Not sure what Mitch does at Trek but I've never tightened a normal threadless headset to 4nm. With the Domane SL/SLR you need to comperess the spring washer so 4nm is needed. It's definitely more than a normal headset. I'll have to try it sometime w/ a torque wrench to see just what happens.


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## 9W9W (Apr 5, 2012)

cxwrench said:


> Since they can't laser etch complete headset adjustment instructions on a top cap I guess they just figured a MAX value would be good enough for most people. Not all people mind you, but most. You can take that for what it's worth, or you can overthink it...


You would think that from a liability perspective there should also be a minimum torque spec, eh?


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## [email protected] (Jan 7, 2019)

cxwrench said:


> Not sure what Mitch does at Trek but I've never tightened a normal threadless headset to 4nm. With the Domane SL/SLR you need to comperess the spring washer so 4nm is needed. It's definitely more than a normal headset. I'll have to try it sometime w/ a torque wrench to see just what happens.


Maybe we're talking about two different items. I was reffering to the cap top bolt which indicates 4Nm on the top. That is the max, but you can use less if your spacers are not able to be moved and the bolt is snug.


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## duriel (Oct 10, 2013)

9W9W said:


> You would think that from a liability perspective there should also be a minimum torque spec, eh?


Once you tighten the stem, you can take that dam thing off and throw it away. There is no minimum!


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## Methodical (Jul 21, 2012)

cxwrench said:


> Interesting. I'm sure I've seen them like yours but just never really noticed because I've seen so many w/ the torque spec on them and just know how tight to make them. That's definitely a part that should have the spec in a visible spot.


CX, I spoke with Trek again and initially the rep stated that the torque spec was 4nm right off the top of the top cap bolt. So, obviously this is very misleading because even the Trek rep thought that was the torque spec because that is what's on the top cap bolt. But, when I pointed out that that's the torque spec for the top cap bolt and not the expander bolt, he had to do some checking. He sent me an email with the Domane SLR install instructions for the expander, which requires 10nm. He stated it's the same install method for the Emonda. I asked if that was the suggested max torque rate and he responded, no the actual spec to use. The instructions seems to allude to using 10nm also. I will post up Trek's response when I get home, but I just wanted to report back my findings.

For some reason, there is no build manual for the Emonda (I can find manuals for Domane and Madone online)...do you have any idea why? Just curious.

Btw, I cut my stem the other day and torqued it to 8nm now.


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## cxwrench (Nov 9, 2004)

[email protected] said:


> Maybe we're talking about two different items. I was reffering to the cap top bolt which indicates 4Nm on the top. That is the max, but you can use less if your spacers are not able to be moved and the bolt is snug.


No, we're talking about the same thing. As I posted before I've never 'torqued' a top cap bolt, and thus a headset, to 4nm. I've never tightened a top cap so that the spacers don't move. I adjust a headset so that it's properly adjusted, nothing more, nothing less. And again, the ONLY headset that has a torque value that should be used is the Domane w/ front IsoSpeed. I think having a torque value on the top cap is somewhat misleading but I guess it's there in an effort to keep ham fisted mechanics from really overdoing it.


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## ToiletSiphon (Jul 23, 2014)

Methodical said:


> CX, I spoke with Trek again and initially the rep stated that the torque spec was 4nm right off the top of the top cap bolt. So, obviously this is very misleading because even the Trek rep thought that was the torque spec because that is what's on the top cap bolt. But, when I pointed out that that's the torque spec for the top cap bolt and not the expander bolt, he had to do some checking. He sent me an email with the Domane SLR install instructions for the expander, which requires 10nm. He stated it's the same install method for the Emonda. I asked if that was the suggested max torque rate and he responded, no the actual spec to use. The instructions seems to allude to using 10nm also. I will post up Trek's response when I get home, but I just wanted to report back my findings.
> 
> For some reason, there is no build manual for the Emonda (I can find manuals for Domane and Madone online)...do you have any idea why? Just curious.
> 
> Btw, I cut my stem the other day and torqued it to 8nm now.


When swapping stems on my Emonda, I noticed my expander had crept up the tube a little bit. I went to put it back in place and realized if was severly undertorqued. Whoever installed it, either at the shop or the factory, probably made the same mistake and torked it to 4nM. 

I contacted Trek to get the proper torque spec (as I could only find it here and on in the Domane manual, I wanted the "official" figure). They said 4nM for the expander, which I pointed out seems awfully low for such a part. They are supposed to get back to me.

Seems like the confusion on this matter is pretty common at Trek.


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## aclinjury (Sep 12, 2011)

Wow, interesting thread. Never knew torqueing a headseat cap can be so confusing!

However, the "torque specs" on the part is the "exact" torque to be used, that's why ther's a number and that's why there's a torque wrench. If it is just a "max torque" number, then it defeats the purpose of having specs in the first place. If you say that 4 Nm is max, then hell anything from 0 Nm to 4 Nm would still be understood as "within spec", doesn't it, and thus having a spec in this fashion is useless.


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## Methodical (Jul 21, 2012)

aclinjury said:


> Wow, interesting thread. Never knew torqueing a headseat cap can be so confusing!


Deleted


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## cxwrench (Nov 9, 2004)

aclinjury said:


> Wow, interesting thread. Never knew torqueing a headseat cap can be so confusing!
> 
> *However, the "torque specs" on the part is the "exact" torque to be used, that's why ther's a number and that's why there's a torque wrench*. If it is just a "max torque" number, then it defeats the purpose of having specs in the first place. If you say that 4 Nm is max, then hell anything from 0 Nm to 4 Nm would still be understood as "within spec", doesn't it, and thus having a spec in this fashion is useless.


No, wrong. Especially with bearing adjustments. There is no torque value that you can measure and tighten to. The bearing(s) are adjusted properly when they're adjusted properly. If you adjust most headsets to 4Nm they'd be too tight. That's why most of them don't have anything on the top cap. There is no correct torque. Stem bolts are generally 'Max 5.2Nm'...don't go over that. If 4.5Nm holds the bar, use 4.5Nm. Bikes are easy...til they're not. 

Unless you have a Trek Domane w/ front IsoSpeed. That h/s should be tightened to 4.0Nm as described previously in this thread.


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## tlg (May 11, 2011)

aclinjury said:


> Wow, interesting thread. Never knew torqueing a headseat cap can be so confusing!
> 
> However, the "torque specs" on the part is the "exact" torque to be used, that's why ther's a number and that's why there's a torque wrench.


Really? So do you torque it wet or dry? Cause that makes a huge difference.
Torque specs are guidelines... not an exact science. If it were an 'exact' torque, it would be a range, and it'd specify wet or dry.



> If it is just a "max torque" number, then it defeats the purpose of having specs in the first place.


When there is a 'max' torque, it's simply to prevent damage.


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## aclinjury (Sep 12, 2011)

On Shimano crankarms, it says torque 12-14 Nm. This is a clear specification.

Maybe Trek is not good at spec'ing stuff.


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## cxwrench (Nov 9, 2004)

aclinjury said:


> On Shimano crankarms, it says torque 12-14 Nm. This is a clear specification.
> 
> Maybe Trek is not good at spec'ing stuff.


That's for the pinch bolts that hold the arm on...you haven't got confused about that have you?

ETA: Nevermind, I think I know what you mean. Yes, that is quite clear and easily understood. But to me so is: Max 4Nm.


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## Methodical (Jul 21, 2012)

cxwrench said:


> No, wrong. Especially with bearing adjustments. There is no torque value that you can measure and tighten to. The bearing(s) are adjusted properly when they're adjusted properly. *If you adjust most headsets to 4Nm they'd be too tight. That's why most of them don't have anything on the top cap.* There is no correct torque. Stem bolts are generally 'Max 5.2Nm'...don't go over that. If 4.5Nm holds the bar, use 4.5Nm. Bikes are easy...til they're not.
> 
> Unless you have a Trek Domane w/ front IsoSpeed. That h/s should be tightened to 4.0Nm as described previously in this thread.


Hence, why it was initially confusing/misleading to me because my Madone doesn't have a NM spec on the top cap (I'd never seen specs on top cap before) and why I thought maybe it was for the steerer plug. That's why I called Trek to get the answer and even the 1st rep thought it was for the steerer plug, until I pressed them on it and then I got the correct answer.


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## ljvb (Dec 10, 2014)

Hmm... standards when it comes to torque specs, generally the number listed, unless it include qualifiers, is what you need to torque it to. Every bolt on machines, vehicles, etc, that has a torque value, you torque it to that value (especially when it comes to TTY bolts... Torque to Yield, or stretch bolts as some call them)

When there is a range, they usually specify a range, or as the poster above noted, adding MAX, which typically is there so you don't split or break the part.

That said, when it comes to parts with bearings, and wear and tear rotational parts where the torque may change over time, obviously the values will differ


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## ToiletSiphon (Jul 23, 2014)

ToiletSiphon said:


> When swapping stems on my Emonda, I noticed my expander had crept up the tube a little bit. I went to put it back in place and realized if was severly undertorqued. Whoever installed it, either at the shop or the factory, probably made the same mistake and torked it to 4nM.
> 
> I contacted Trek to get the proper torque spec (as I could only find it here and on in the Domane manual, I wanted the "official" figure). They said 4nM for the expander, which I pointed out seems awfully low for such a part. They are supposed to get back to me.
> 
> Seems like the confusion on this matter is pretty common at Trek.


Well, they got back to me after a few days. Apparently the number is now 8nM for the expander in the carbon fork of the Emonda ALR. Seems more reasonable, but Trek is definitely all over the place on that.


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