# Compression plug vs. star nut



## tourdreamer (Sep 7, 2004)

I recently purchased a Zipp 145 stem and noticed that it also came with a very cool Zipp top cap. The top cap looks like it will only fit a star nut assembly. The problem is my current setup uses a compression plug. Is there a way to make this top cap work on a compression plug type assembly? My fork has a carbon steerer tube and don't want to switch to the star nut type. I read that compression plugs are the best type for carbon. Thanks.


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## C-40 (Feb 4, 2004)

*star nut not an option...*

A star nut is only used with metal steering tubes. A star nut would damage a CF steering tube and not properly support the stem clamp area.

There is more than one type of compression plug. I assume that your top cap has a standard M6 bolt in the center? That would be compatible with a star nut.

Some brands of compression plugs also accomodate an M6 bolt. Colnago's does, as does the older design used by LOOK. Others now use a top cap with a large diameter internal thread, like the new LOOK model and those made by FSA. Those won't do you any good.


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## tourdreamer (Sep 7, 2004)

Thanks C-40 for the reply. My current compression plug is the new version that has the large diameter internal thread as part of the top cap...just like the FSA plugs. The Zipp top cap looks just like this. I'll do a search on the Colnago plugs that will accomodate an M6 bolt. It's just that the Zipp top cap just looks too cool to not use it. It would definitely finish off the stem nice.


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## Richard (Feb 17, 2006)

And that huge Colnago plug just about negates any weight advantage of a carbon steerer vs. alloy. Colnago made it that way to offset stem clamping forces.

I've got the FSA's in both my carbon forks (even the alloy steerer one) and they function great. My Masi came with that little "sawtooth" double-ring thingymaggigy on the Easton EC90/FSA integrated headset. No star nut or compression plug needed (and no reinforcement against stem clamping either.) Headset wouldn't stay adjusted to save its or my life. Replaced it with the FSA compression plug with the sexy carbon top cap and no problems since.


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## C-40 (Feb 4, 2004)

*LOOK is lightweight...*

Weight weenies again. 

The idea is to support the entire stem clamp area. Colnago's plug is long, but no where near that heavy. The LOOK model can be reduced to nothing but the two small aluminum pieces. Toss the spring and washers, after the plug is expanded the first time. Then it's a fraction of the weight of an FSA.


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## tourdreamer (Sep 7, 2004)

*Profile Design has something that'll work*

Stopped by an LBS during lunch and was shown a product by Profile Design...it's compression plug for a carbon fork steerer that uses a normal top cap. Check it out. I haven't been able to find the Colnago or Look plugs that were referred to in earlier posts but they may be similar to the Profile Design. I'm gonna give this one a shot.


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## percy (May 17, 2004)

If you're in the market for a new fork, take a look at Alpha Q. They have a full carbon steerer but use an aluminum sleeve inside the top of the steerer that has a pre-installed star nut, so you can use whatever top cap you'd like. Seems like a good setup. I like mine.


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## tourdreamer (Sep 7, 2004)

I saw the Alpha Q sleeve when I was doing my research but it looks like the sleeve and adhesive used would cancel out any weight advantage of a carbon steerer. I know, I know...we're all weight weenies.


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## C-40 (Feb 4, 2004)

*may not fit...*



tourdreamer said:


> I saw the Alpha Q sleeve when I was doing my research but it looks like the sleeve and adhesive used would cancel out any weight advantage of a carbon steerer. I know, I know...we're all weight weenies.


The steering tube on Alpha Q forks has thinner walls than most other brands, which makes the ID larger. The aluminum tube may not fit into some other brands. It's not all that light either, but would solve the star nut problem.

I've actually epoxied a slightly ground down 1" star nut into a 1-1/8 inch carbon steering tube. Obviously it's a permanent approach that I don't recommend to others, but it is possible.


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## Rugby11 (Sep 25, 2003)

How does the compression plug vs the insert factor in the weight of the fork.


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## Clevor (Sep 8, 2005)

I've been researching this subject lately for my dream C50 build. The Colnago expander plug feels heavier than it is: 55 gms. Token makes some substitutes but they come out to around 38 gms. For me, it's not worth it (not the cost, the weight loss).

Somebody on WeightWeenies gave a link to some stuff that weighs around 10 gms, but every one of these expander plug substitutes are not as long as the stock Colnago plug. I don't know what fork you guys are running, but you really would NOT want to crack the steerer on a $900 Star fork, especially one with a special paint job, so I wonder whether it's worth it.

Somebody mentioned on another post about just using a thin wall Alu rod epoxied to the inside of the steerer. Maybe something around 3.5" long. Is it easy to find one that just fits the inside diameter, and any confirmed weights if you go this route?


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