Carbon steerers allow for lighter weight forks, but they do come with some special handling instructions. One of those is not to use a starnut like you’d typically find in a metal steerer. Instead, most carbon forks rely on compression plugs – like the one that Wolf Tooth Components has offered for a while. Only now, there’s a new way to purchase it which includes their 5mm stem cap.

Wolf Tooth Components Compression plug with integrated spacer stem cap

Technically, there are now two options for compression plugs from WTC. They still offer their existing Compression Plug for $14.95. That’s just the silver plug that fits inside a 1 1/8″ carbon steerer, and expands as you tighten down the integrated bolt to wedge itself in place. With this version, you need to supply your own stem cap and stem cap bolt.

Now, there is an option to purchase the Compression Plug with Integrated Spacer Stem Cap. Take the existing Compression Plug and add in their Ultralight Stem Cap with Integrated spacer, and you have the new plug option. That Integrated Spacer means that you won’t need to add an additional spacer on top of your stem. Most carbon steerer manufacturers recommend running them long enough so there is steerer protruding from the top of the stem so you don’t damage the carbon with your stem clamp. So if you want to run as few spacers as possible, while still running the proper steerer length, this is a good way to do it.

Wolf Tooth Components Compression plug with integrated spacer stem cap installed

Of course, it’s also available in eight different colors so you can color match everything. Or not. You have your choice of Black, Red, Blue, Green, Orange, Silver, Purple, and Gold which are offered throughout the WTC line in other products as well.

Made from 7075-T6 aluminum, the complete unit weighs in at a claimed 38g, with an insertion depth of 28mm. The Compression Plug with Integrated Spacer Stem Cap is available now, and priced at $24.95.



      • I think there’s a reason why they left this compression plug short. If it is the full 40mm, stress will be on an unsupported steerer tube. This will allow the steerer tube to distort and stress will be concentrated on one edge, right where both the clamp and the plug terminate. By offsetting, leaving the plug short the flex will happen in that 12 mm band, an unclamped area with the plug inside, thereby keeping it from folding in. And that folding is what concentrates the stress. Not desirable.

        While my experience is limited in dealing with steerer tubes and carbon, I do understand stress and fatigue from four decades in metal fab.

        Comment are therefore welcomed.

        There is however one thing that does perplex me. Why do they call it a compression plug when it should be called and expansion plug? Compression is something that happens with the clamp.

        • I don’t understand your stress reasoning at all. A plug that goes the full length of the stem is far preferable and helps with counteracting stress concentrations. Also, the more contact area the better to prevent slip.

          A tight-fitting metal sleeve epoxied to the inside of the steerer is a far better solution in very case, IMO, and allows use of a regular starnut without worry.

          The correct term for these is expander plugs. I have no idea why anyone would call them compression plugs; – anti-compression plugs maybe.

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