Headset adjustment on a 1" carbon steerer

[farmallguy]

I recently picked up a Pegoretti Palosanto with a Mizuno fork, 1 inch carbon steerer. When I went to install the stem, it was disassembled to ship it to me, when I was surprised to see the top cap on the steerer was an expanding type. How was I going to adjust the play in the headset without a star nut in the steerer tube? This is new to me so I am looking for the proper way to make the adjustment.

Am I correct in assuming that you shouldn't put a star nut in a carbon steerer? I am all ears, thanks for the help folks.

Jack

[stien]

Expander plug in a carbon steerer, no star nut! Any lbs should have one.

[fogrider]

Yeah, drop the expanding unit into place and there should be a bolt to expand it so its tight. Then you should be able to tighten the cap over the stem. Once the stem bolts are tight, you're good.

[farmallguy]

Yeah, drop the expanding unit into place and there should be a bolt to expand it so its tight. Then you should be able to tighten the cap over the stem. Once the stem bolts are tight, you're good.

Yeah, I got that, but how do you adjust the play in the headset? What process takes the place of adjusting the screw in the top cap/ star nut combo to remove any play before you tighten the stem clamp on the steerer?

Thanks

Jack

[lhuerta]

Per Fogriders instructions....first you set the expander plug in the steer tube (essentially works/takes place of the star nut), then you use the top cap and screw to set compression on bearings.

How to adjust a threadless headset:

https://www.youtube.com/watch?v=Gag5ZINFRAw&list=PLe2rWZ6kNqvKKpTQoVEkw_JNf3whesHRL&index=12

http://www.parktool.com/blog/repair-help/threadless-headset-service

[bikinchris]

1. Use the no slip carbon prep.
2. Install the expander ( a star nut would split the carbon steerer open, ruining it.
3. Tighten the expander with a 6mm allen wrench. Sometimes, holding it with pliers may be necessary.
4. Stack your spacers and stem, leaving about 3mm of space above the steer tube.
5. The inside of the 6mm nut you used to tighten the expander is threaded for the bolt going through the top cap of your headset.

[buldogge]

Hey... I'm not 100% on what you are asking?...Have you not installed/adjusted a threadless set-up before??

Perhaps the Mizuno includes the expander type that Reynolds and Enve use...if so then you use both a 5mm and 6mm Allen key to install/adjust.

The 5mm tightens the expander in place and the 6mm turns the top cap. Leave the stem loose as usual, tighten the cap to set the bearing preload..set the stem and torque.

-Mark in, umm, somewhere between Nashville and Paducah

[farmallguy]

Duh, now I get it. I didn't realize that there were separate screws for the expander and the top cap. thanks guys! Knew I was missing something but didn't know what.

Jack

[farmallguy]

Also, is there a recommended torque for the expander bolt?

[thwart]

Also, is there a recommended torque for the expander bolt?

As a rough rule of thumb (and assuming carbon paste on assembly), if you tighten the top cap to snug up the headset and you can't fully tighten it down (indicating the expander is slipping upwards), disassemble and use your 6 mm allen to tighten the expander 'a bit' more.

Maybe one of the folks here who are pro mechanics has a more exact method...

[lhuerta]

....remember that that the expander plug or start nut is simply there to allow for the MINIMAL compression needed to set your bearing preload. There is no need to over torque, simply tighten enough to allow the top cap to engage the needed preload (e.g. 5 Nm should b sufficient, however, depending on the fit with your plug, more maybe needed.). Don't fret the carbon steerer...unless you are ham fisted you will not damage the steerer.

Here is a thread on this issue;

http://forums.thepaceline.net/showthread.php?t=122676

[pdmtong]

Duh, now I get it. I didn't realize that there were separate screws for the expander and the top cap. thanks guys! Knew I was missing something but didn't know what.

Jack

like this? personally I don't care for this style of plug and favor the current enve style barrel expander. the latter I find much easier to set and forget.

[cbresciani]

My Colnago C40 HP has a one inch carbon steerer tube that came with a star nut originally installed. 10 years later it still seems to be working fine without any issues. Although the carbon steerer tube on the C40 is pretty beefy. I guess the expander bolt would probably be a better bet but...