carbon steerer expander plug

[AngryScientist]

damnit; frustrated.

my new-to-me swisscross came with a kcnc expander plug for the steerer.

the way this one works is you use a 4mm hex to tighten the expander (counter clockwise) into the steerer tube, and then the 5mm hex bolt preloads the top cap (clockwise tighten).

i've tried everything i can think of to keep the expander tight when i tighten the top cap. even used blue locktite overnight on it.

no dice.

after some harsh gravel this weekend, and my top cap rattling loose every couple hours, i'm ready to throw this thing in the bin.

any advice or should i get a different, better expander?

[donevwil]

Best expander bar none is from Specialized, appears they are still available (https://www.amaincycling.com/specialized-carbon-steerer-tube-plug-rd-mtn-06214-2010/p691196?gclid=CK3j16_E3-ICFc4grQYdOFkIUw). Replaced the POS Enve expander than came in a 2.0.

https://images.amain.com/images/large/bikes/specialized/06214-2010.jpg?width=475

[AngryScientist]

that's good enough for me!

@ 10 bucks, i'm just ordering one.

thankss!

[billspreston]

That Specialized expander is great - unless you have to remove it! If you're like me and cut your steerer a few times before settling on a spot, it's a pain to remove and something to consider.

Have you tried opening up the KCNC expander a bit outside of steerer so it has some friction fit and you kind of have to pop it down in with your hand? That should give the expander the purchase it needs to grip the steerer tube when you turn the bolt. I've had to do this with Enve expanders on occasion.

[donevwil]

That Specialized expander is great - unless you have to remove it! ...

Made me laugh, had a similar experience but finally did get it out. Fortunately steerer had already been cut to length so it was a one-time challange.

[GregL]

I've used KCNC expanders on several bikes with good results. I like the fact that the KCNC expander has a greater useable expansion range than some of the simple "plug-type" expanders. This makes it work better in steerers with larger inner diameters (thinner walls) than standard.

I'll echo billspreston's recommendation to make sure the KCNC expander is opened as much as possible before inserting it into the steerer tube. With the inner, 4mm bolt tightened sufficiently, I've never had one of mine come loose.

Greg

[R3awak3n]

Made me laugh, had a similar experience but finally did get it out. Fortunately steerer had already been cut to length so it was a one-time challange.

I had one break in my new OPEN (lets say I installed it wrongish) and for a second I thought the fork was going to be toast cuz I could not get it out.

Its a good expander but won't be using it anymore because that was a pretty frustrating experience. Deda has a similar one and I really liked that one but seems impossible to find now (even the spesh was hard to find). I ended up just using the one that came with the bike and also has been fine. I think I have 2 enve forks that have the enve expander and also has been fine. I do like these longer expanders for obvious reasons but man that spesh situation had me sweating.

[saab2000]

I never had any issue with the Specialized. Have several and wish I had more. If they’re still available I may order more. They’re the best.

[MagicHour]

Does it look like these? Maybe try and find one that is all knurls and less smooth areas? I have BBB Powerhead that has worked really well when a factory supplied unit constantly slipped on me.
Wipe down inside steerer and bung with alcohol and then use a little carbon paste. Make sure and use proper mfr torque specs if you can find them, usually ~5nm or I've seen as high as 8nm - but don't think I have the nards to twist one of these up that snug. And torque it with the stem in place to prevent bulging steerer.


https://cdn10.bigcommerce.com/s-tqfdy/products/503/images/3307/kcnc_expanderplugs__27127.1448488417.1280.1280_org __50377.1468796326.500.750.jpg?c=2

[johnniecakes]

I have used these origin 8 expanders with great success. I have used them in carbon and steel steerer tubes. You buy them direct or from Amazon.

http://product.origin8.bike/?page_id=224&prod_model_uid=16532

[Veloo]

Here's a long one if you're using a lot of spacers.

https://www.chainreactioncycles.com/ca/en/colnago-fork-expander/rp-prod70234

[vqdriver]

Expanders seem to be one of those things that are easy to over engineer. Most of mine have worked fine with the exception of enve. easiest is a cheapo fsa

[JeffWarner]

What makes the Specialized plug so hard to get out? It looks similar design (split sleeve with two conical end plugs) to the ENVE plug that I’m using...just longer. I’ve always like the idea if the longer plunge but could never find the Specialized part when I needed one.


I had one break in my new OPEN (lets say I installed it wrongish) and for a second I thought the fork was going to be toast cuz I could not get it out.

Its a good expander but won't be using it anymore because that was a pretty frustrating experience. Deda has a similar one and I really liked that one but seems impossible to find now (even the spesh was hard to find). I ended up just using the one that came with the bike and also has been fine. I think I have 2 enve forks that have the enve expander and also has been fine. I do like these longer expanders for obvious reasons but man that spesh situation had me sweating.

That Specialized expander is great - unless you have to remove it! If you're like me and cut your steerer a few times before settling on a spot, it's a pain to remove and something to consider.

Have you tried opening up the KCNC expander a bit outside of steerer so it has some friction fit and you kind of have to pop it down in with your hand? That should give the expander the purchase it needs to grip the steerer tube when you turn the bolt. I've had to do this with Enve expanders on occasion.










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[el cheapo]

This happened to me. Kept trying to tighten the cap and it would always come loose. Thinking it was a major problem decided to mention it to my favorite bike mechanic. Told me to put a simple carbon spacer under the cap. A one dollar fix, it's stayed tight for the last six years. Hope this helps.

[Dino Suegiù]

That Specialized expander is great - unless you have to remove it! If you're like me and cut your steerer a few times before settling on a spot, it's a pain to remove and something to consider.
Made me laugh, had a similar experience but finally did get it out. Fortunately steerer had already been cut to length so it was a one-time challange.
I had one break in my new OPEN (lets say I installed it wrongish) and for a second I thought the fork was going to be toast cuz I could not get it out. Its a good expander but won't be using it anymore because that was a pretty frustrating experience. Deda has a similar one and I really liked that one but seems impossible to find now (even the spesh was hard to find).

What makes the Specialized plug so hard to get out? It looks similar design (split sleeve with two conical end plugs) to the ENVE plug that I’m using...just longer.
It really isn't so difficult at all.
Here is a good quick video:
https://www.youtube.com/watch?v=YNizysonc74

The best I have used are Deda, Colnago, Specialized; the worst ENVE and tune.

[fignon's barber]

damnit; frustrated.

my new-to-me swisscross came with a kcnc expander plug for the steerer.

the way this one works is you use a 4mm hex to tighten the expander (counter clockwise) into the steerer tube, and then the 5mm hex bolt preloads the top cap (clockwise tighten).

i've tried everything i can think of to keep the expander tight when i tighten the top cap. even used blue locktite overnight on it.

no dice.

after some harsh gravel this weekend, and my top cap rattling loose every couple hours, i'm ready to throw this thing in the bin.

any advice or should i get a different, better expander?


It has been my experience that if the expander won't hold, it's not the expander that is the root cause. It's either an issue with the headset (possibly doesn't fit ht cup size) or maybe you need a small 5mm spacer between cap and stem.

[AngryScientist]

to expand a bit: my problem is not that the expander is slipping; the problem is that when i tighten the top cap bolt (clockwise) it loosens the expander loading bolt (which is reverse threaded).

i ordered one of the spec ones, but in the mean time, i put even more locktite on that bolt and will let it sit overnight before installing the top cap.

i already have the headset preloaded fine, and the stem is keeping everything tight, it's just that the top cap bolt keeps coming loose on really rough road surfaces.

[cribbit]

Why is the expander bolt reverse threaded?

I have cheapo chinese ones that work great.

Also @ the long expander - I thought these are supposed to seat at the edge of the steer tube no matter what, with the same diameter as the tube? It would go inside of any spacers.

[skiezo]

I have been using these on my road bikes and really like them. I can take it in and out without any damage to the carbon steer tube. Not sure how it would work on a gravel ride.
https://fairwheelbikes.com/tune-gum-gum-expander-plug/

[pdmtong]

Best expander bar none is from Specialized, appears they are still available (https://www.amaincycling.com/specialized-carbon-steerer-tube-plug-rd-mtn-06214-2010/p691196?gclid=CK3j16_E3-ICFc4grQYdOFkIUw). Replaced the POS Enve expander than came in a 2.0.

https://images.amain.com/images/large/bikes/specialized/06214-2010.jpg?width=475

that's good enough for me!
@ 10 bucks, i'm just ordering one.
thankss!

you guys know AMain is the reincarnation of Performance and Nashbar...
https://www.bicycling.com/news/a26304827/performance-bicycle-closing/

[JeffWarner]

It really isn't so difficult at all.

Here is a good quick video:

https://www.youtube.com/watch?v=YNizysonc74



The best I have used are Deda, Colnago, Specialized; the worst ENVE and tune.



Nice trick! Thanks for the video link.

I do the first part (loosen the bolt and tap) to get the ENVE expander lose, but leveraging out the top with a tool is something new.



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[pdmtong]

Nice trick! Thanks for the video link.
I do the first part (loosen the bolt and tap) to get the ENVE expander lose, but leveraging out the top with a tool is something new.
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agreed thanks for the video!

[Dave]

Fsa expanding plugs work OK, but after I get the steering tube length right, I epoxy glue in a 1 inch star nut and never have to bother with one again.

[El Chaba]

You need to know the proper stem height, but I generally use JB weld to secure the plug. You need to install a "dummy" bolt with a bit of grease on it to keep the adjustment plug threads clear, but a layer on top of the plug keeps things in place forever. I have fixed at least a dozen cases of headsets repeatedly coming loose for friends. The recidivism rate is zero.

[jc031699]

Adding this to the archive

https://uploads.tapatalk-cdn.com/20190721/0cd15de6e316b1e08107e08bf30bde3a.jpg


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[Gummee]

Talked to the local SBC dealer. They told me $20 for that expander.

Despite working in another shop, that $10 wedge from amain is still a great deal

M

[AngryScientist]

yup.

to close the loop on my own thread, i got that specialized one. it is 1000x better than what i started with. perfect. zero problems now. satisfied customer.

[m_sasso]

I have been using these on my road bikes and really like them. I can take it in and out without any damage to the carbon steer tube. Not sure how it would work on a gravel ride.
https://fairwheelbikes.com/tune-gum-gum-expander-plug/

Fsa expanding plugs work OK, but after I get the steering tube length right, I epoxy glue in a 1 inch star nut and never have to bother with one again.

A proper carbon steerer compression plug needs to provide two functions

1.) Provide compression for the head set stack.
2.) Provide support to the diameter of the carbon steerer tube being clamp compression loaded through the steering stem.

Those small surface area, any thing less than 40+mm in height compression plugs and star nut plugs satisfy function 1.) Provide compression for the head set stack, perfectly however fail miserably at function 2.) Provide support to the diameter of the carbon steerer tube being clamp compression loaded through the steering stem.

If you use one better have a real good helmet, an outstanding dental plan and familiarity with a good facial plastic surgeon, they are dangerous, and consumer protection should outlaw them for ignorant peoples protection. Hit a bump hard and your stem crushes your unsupported carbon steerer tube and you will hit the pavement before you even know what was happening.

Don't take my comments seriously here watch this, https://www.youtube.com/watch?v=8bSnbjHiFXc

[tigoat]

This new version of Specialized plug is not as good the old one. The old one did not have those teeth on the top and you could pull it out without removing the bolt completely. To remove the old version, just loosen the bolt and give it a light tap to knock the plug down and then pull the whole unit out. I have a box full of them that will last me a lifetime.

[YesNdeed]

I had to look into expander plugs and their various designs a few years ago. After building up a F/F/HS I bought from a friend, the HS just wouldn't stay tight. I'm super happy I didn't die during that time. Unlike Angry's problem, the expander plug was in fact slipping. I think I replaced it with an FSA, but don't really remember. The rough surface area that came in contact with the inside of the steerer tube was way too smooth, and a new one fixed the problem for about $15. It was a nice relief to take the mystery out of what's going on in there.

[rowebr]

Adding this to the archive

https://uploads.tapatalk-cdn.com/20190721/0cd15de6e316b1e08107e08bf30bde3a.jpg


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Thank you for this! The only instructions from Specialized that I could find online just say to "Remove the expander plug." So totally unhelpful.

[Dino Suegiù]

I have been using these on my road bikes and really like them. I can take it in and out without any damage to the carbon steer tube. Not sure how it would work on a gravel ride.
https://fairwheelbikes.com/tune-gum-gum-expander-plug/

If you want a never-used tune Gum Gum one (I may even have two of them) as a a spare, etc., for much less than retail just PM me. Some people love them, but I have no need for mine.

[DRietz]

What problems do people have with Enve expanders? I've never had an issue.

[Ralph]

My ENVE plug works great. As I recall......when I installed it some years ago.....adjusted it so I had to tap it in with a rubber hammer, snugged it up some more.....and after several different stems....never touched it again.

[Dino Suegiù]

What problems do people have with Enve expanders? I've never had an issue.
My ENVE plug works great. As I recall......when I installed it some years ago.....adjusted it so I had to tap it in with a rubber hammer, snugged it up some more.....and after several different stems....never touched it again.

A lot of people do like them, and they seem well made, but I never had that much luck feeling secure with mine.

Basically though it comes to that I really prefer that the length equal or exceed the stem stack (the ENVE effective insertion length is only ~28mm long).

But, again, they are designed/spec'd by people who make great forks, so I'm sure they are good.

EDIT: this Raoul Luescher video is good: Quicktips - Fork steerer compression plugs (https://www.youtube.com/watch?v=8bSnbjHiFXc)

[Gummee]

I had to look into expander plugs and their various designs a few years ago. After building up a F/F/HS I bought from a friend, the HS just wouldn't stay tight. I'm super happy I didn't die during that time. Unlike Angry's problem, the expander plug was in fact slipping. I think I replaced it with an FSA, but don't really remember. The rough surface area that came in contact with the inside of the steerer tube was way too smooth, and a new one fixed the problem for about $15. It was a nice relief to take the mystery out of what's going on in there.

I've got a pair of CX bikes that the plug slips up in the steerer and makes the headset loose.

I'm hoping the SBC plugs will help that situation

M

[jc031699]

I've got a pair of CX bikes that the plug slips up in the steerer and makes the headset loose.



I'm hoping the SBC plugs will help that situation



M



I’m not sure I understand how the compression plug loosening affects a properly adjusted headset held in compression by a properly torqued stem clamp? There are some who remove the top cap entirely after adjusting the headset and torquing down the stem clamp bolts.

Angry’s problem was a different one, I gather; the compression plug slipping was preventing him from adjusting the headset properly or causing the top cap to rattle around on rough roads once the headset was properly adjusted and secured by the stem.


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