Best expander plug with or without weight being a factor?

[alcatraz]

Some things to consider regarding slippage:

1. Not all bikes have the same fork inner tube surface smoothness. Your results could vary.

2. Torquing to the maximum specified ~8Nm for the light ones would possibly overtorque it as the tube wall becomes compressed by the stem on flexy fork tubes. Maybe avoid max torque unless you experience slippage.

3. Grabbing more surface could result in slippage. I found the extralite thin lip design to have less slippage than semilight 10gr with larger contact surfaces.

What solved many issues for us was to use a torque wrench and torque the light expanders to their max (without the stem) to get minimal slippage. If your loosened stem binds easily you might find preloading the headset with a light expander troublesome. Check the stem for burrs and go easy on the antislip paste if you use it. Ideally I'd want a stem that when loose, doesn't require too much effort to position. Not all are like that.

[Lewn777]

Some things to consider regarding slippage:

1. Not all bikes have the same fork inner tube surface smoothness. Your results could vary.

2. Torquing to the maximum specified ~8Nm for the light ones would possibly overtorque it as the tube wall becomes compressed by the stem on flexy fork tubes. Maybe avoid max torque unless you experience slippage.

3. Grabbing more surface could result in slippage. I found the extralite thin lip design to have less slippage than semilight 10gr with larger contact surfaces.

What solved many issues for us was to use a torque wrench and torque the light expanders to their max (without the stem) to get minimal slippage. If your loosened stem binds easily you might find preloading the headset with a light expander troublesome. Check the stem for burrs and go easy on the antislip paste if you use it. Ideally I'd want a stem that when loose, doesn't require too much effort to position. Not all are like that.

Interesting post. So you're saying that a smaller plug surface area reduces the chances as slipping as the pressure is in a smaller area?

Some people say rubber o-rings or even old inner tube has helped them prevent slipping, can anyoen confirm this?

[PinaRene]

Carbon - ti with Riesel topcap on 2 out of 3 bikes - they don't slip with topcap on 3Nm and it's enough for bearing preload. Did cobble rides - bad roads and they still are perfect. Ordered @ R2 bikeshop in Germany.

Cobble rides are a great test, and 3nm is a good torque, this seems like a good option. Thanks.
What torque are you using on the plug? 6nm?

Torque for the plug/ extender max 4Nm and stem bolts also 4Nm , works well for me.

[Lewn777]

The carbon-ti exapnder can be only 4nm without slipping? Impressive.
I'm running 8nm plug, and 2-3nm extender, still slips sooner or later. I just want set and forget.

[alcatraz]

I noticed your chinese grammar there Lewn777.

I'm struggling to remember mine after being there 5+ years.

[Lewn777]

17 years, y u no think my grammar good?

[Discodan]

I’ve been using a Hope head doctor for many years without fault; 30 bucks and 30 grams so reasonable.

It shouldn’t be hard to make a expander that has a reasonable ‘grab’ area and supports a decent length of the steerer from crushing, it’s not hard engineering and we probably could have made these as school metalwork projects if we had the need back then.

I think I’ll get one of these for a loss cost trial; 4 bucks for 30 grams with a decent support depth. Does anyone think the knurled finish would in anyway point load the carbon

https://www.aliexpress.com/item/1PC-lot ... 42665.html

An AliExpress WW option; 7 bucks for 7 grams. I’m not going to go there are it seems it relies on 3 ridges of 1mm to grip and support the steerer, it much work but I’m not too comfortable. How does that compare in terms of support to the established suppliers?

https://www.aliexpress.com/item/ZTTO-Bi ... 21314.html




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[dgasmd]

I have used the 2 below with out an issue at all. Got them with the same brand cap. Pretty damn light!

[Meyercord]

I’ve been using a Hope head doctor for many years without fault; 30 bucks and 30 grams so reasonable.

It shouldn’t be hard to make a expander that has a reasonable ‘grab’ area and supports a decent length of the steerer from crushing, it’s not hard engineering and we probably could have made these as school metalwork projects if we had the need back then.

I think I’ll get one of these for a loss cost trial; 4 bucks for 30 grams with a decent support depth. Does anyone think the knurled finish would in anyway point load the carbon

https://www.aliexpress.com/item/1PC-lot ... 42665.html

An AliExpress WW option; 7 bucks for 7 grams. I’m not going to go there are it seems it relies on 3 ridges of 1mm to grip and support the steerer, it much work but I’m not too comfortable. How does that compare in terms of support to the established suppliers?

https://www.aliexpress.com/item/ZTTO-Bi ... 21314.html




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Those are just clones of carbon ti and extralite expanders. I’ve used both(the real ones) and both work fine.

[FIJIGabe]

FIJI: Is this the Bontrager you're using?
https://www.tritoncycles.co.uk/componen ... cap-p20914

It looks like it, but it's just the OEM one that came with my Emonda.

[eric01]

The specialized plug is pretty good. It’s longish and relatively light weight. Less than 30g if I recall correctly

[dastott]

Had slippage with the light Cannondale one recently. Have put the heavy (50g) Cannondale one back on so this thread is well timed for me. Thanks.

I initially had slippage when I went to the lighter one. Use a bit of carbon paste and haven’t had issues since.

Getting slippage with the heavy Cannondale one now too. Time to try carbon paste. Sorry for the newbie question, but where to apply the paste exactly? On the expander plug where it meets the inside of steerer, or where the stem meets the outside of steerer, or somewhere else? Thanks.

[alcatraz]

Had slippage with the light Cannondale one recently. Have put the heavy (50g) Cannondale one back on so this thread is well timed for me. Thanks.

I initially had slippage when I went to the lighter one. Use a bit of carbon paste and haven’t had issues since.

Getting slippage with the heavy Cannondale one now too. Time to try carbon paste. Sorry for the newbie question, but where to apply the paste exactly? On the expander plug where it meets the inside of steerer, or where the stem meets the outside of steerer, or somewhere else? Thanks.

At the contact points where you want to increase friction. For a compression plug this means on the steerer tube inner wall.

Just pay attention not to get it into bearings, threads, or where you don't want friction.

I find it difficult to mount a stem as the stem will scrape the paste onto the headset cap where I don't want the stuff. I guess the best way is just to apply it sparingly.

[dastott]

Many thanks. I have a feeling that the top bearing just under the stem keeps coming loose (because it is not seated properly?). Never had this issue before so it's very puzzling.

[alcatraz]

Is the bearing seat ovalized or is your headset simply losing compression?

Are you torquing the stem bolts to their max and in small increments left/right?

Carbon paste helps too.

If my bearing seat were ovalized I'd try some retaining compound a la loctite 641. I'd leave it to set with preload overnight before riding to avoid it coming loose before the compount has dried.