By Rick Schultz
- Very Large surface area offers carbon steerer tube full support against over-compression from overtightening the stems’ pinch bolts.
- Easy / simple installation
- Low cost for the protection it offers
- None Identified
Price MSRP: $24.99
Source: Bike shops, Websites
Features: 6000series aluminum expansion wedges w/knurled sleeve
How Obtained: Manufacturers sample
Summary: One of the best full sized expansion plugs available
I’ve always been a huge supporter of Cane Creek products and use their headsets exclusively. When my 2014 Giant TCR Advanced carbon fork developed a hairline crack, it was time to quickly replace it. Luckily I had a spare Enve carbon fork laying around. The problem was that the Enve fork was a 2020 model and did not fit the 2014 Giant headset. A quick call to Cane Creek tech support supplied me with which headset I needed. In the meantime, waiting for the headset to arrive (unfortunately the Ancora didn’t exist back then), but fortunately, I had a spare Cervelo steel sleeve for carbon steerers (the one that gets epoxied into the steerer tube) that I started prepping the new fork with. With this solution, I could safely insert a star-nut.
Several days later the headset arrived and that’s where the second problem surfaced. As I tightened the center stem bolt, the headset bottomed out on the top of the head tube and the fork wouldn’t turn. A second call into Cane Creek quickly resolved that problem as well. Their solution was for me to install shim spacers that fit between the top of the upper bearing and the stem hat/cap. I bought a set and after they arrived, I finished the installation and I’m still riding the bike today!
Fast forward to several months ago where I described my build process for prepping a stem, selecting and installing the correct compression plug see – https://www.roadbikerider.com/bicycle-carbon-steerer-tubes-and-safety/.
There are severe and sometimes fatal consequences for skipping stem prep steps. Here is a graphic illustration. Carbon is strong but fails instantaneously. Ill-prepped stems, choosing an inadequate compression plug or the wrong compression plug, overtightening the stem’s pinch bolts – anyone of these can easily lead to a crack in your carbon steerer tube. And, to make a potentially catastrophic steerer issue even worse is the fact that not all steerers are created equally – see below.
The steerer tube on the left is from a Giant TCR advanced, the one on the right Orbea Orca. Notice 2 differences?
Wall thickness – Giant = 6mm, Orbea = 3mm
Center material – Giant = aluminum reinforced carbon, Orbea = carbon.
Which fork would you trust more?
The figure above shows several different ‘expansion or compression plugs’
- DO NOT USE ON CARBON
- NOT GREAT since the stem needs to clamp over the expansion part towards the bottom of the plug
- Carbon steerer tube with crack
- BEST OPTION allowing the stem the most adjustability and to clamp where there is SUPPORT
Extremely simple, easy and foolproof installation. Just slide the ANCORA into the steerer tube and tighten with a 6mm hex wrench. Add top cap and you are done!
If you would like one for yourself, check out: https://canecreek.com/product/ancora/
6000 series machined aluminum expansion wedges paired with a knurled sleeve to ensure a secure preload.
Note: Top cap sold separately.
Coach Rick Schultz is an avid cyclist who trains, races and coaches in Southern California. Rick is an engineer by trade, and in addition to being a coach, he’s a bike fitter and prolific product reviewer. He’s the author of Stretching & Core Strengthening for the Cyclist in the RBR eBookstore. Check his product reviews website, www.biketestreviews.com, and his coaching site, www.bikefitnesscoaching.com. Click to read Rick’s full bio.
Kenneth Pierce says
How does the expansion plug or star nut fit in-between the center reinforced section of the steerer tube? And, if it is the lower section of steerer tube with reinforcements its moot as the most stress is on the last 4 inches or so of steerer tube.
The number 2 plug in the photo is quite strong, in fact I bet it is just as strong as your cane creek expander plug. The top part of #2 is meant to take all the stress of the stem clamp, the 1in gap between upper and lower sections is negligible. Most steerer tubes crack from over tightening the top pinch bolt of the stem, thats why #2 plug is solid up to the cap, a kind of idiot proofing. I’ve used many variations of the #2 plug for well over ten years on multiple bikes with never an issue. But, I torque my all my cockpit bolts to 4-5Nm. I too have an ENVE fork that came with a expander plug and it will not get tight enough for safe use, it spins well before it gets tight enough, I do not and will not trust it. I’m not trying to be disrespectful, just trying to say that if you do not have the skills or aptitude to install a modern headset then don’t, get a professional to do it.. The majority of damage comes from incorrect installation. I’m a big fan of BB30 and in 15 years of using them on multiple bike I’ve never had an issue. Working with Cdales for years I find it is poor installation and poor maintenance that causes the majority of problems.
Happy Holidays to you and the family.
The Ancora looks like a great plug for carbon steerers. Specialized used to sell a similar style plug years ago which I found very useful , but I have not seen one recently. Used one of those #2 style plugs in the past but found them of minimal help for the steerer ‘spin despite adequate preload” issue. The Ancora’s much larger surface area of support & gripping the inside of the steerer tube seems like a meaningful advantage, and at a reasonable cost.
Brian Nystrom says
It’s important to keep in mind the bike manufacturers don’t necessarily make their carbon forks to common internal diameter standards. My 2018 Cannondale SuperSix EVO Hi-Mod is one such bike. The recommended top cap assembly offers very little support to the steerer, but the tube walls are thicker than standard and don’t need extra support, according to Cannondale. Typical top cap/wedge assemblies won’t even fit, as they’re too large in diameter.