Advice on Steerer Tube damage

I have a Neil Pryde Alyze, a small boutique-y, aero race bike that I’ve loved for five years now. Light, handles great, a blast to ride. I took it into my bike shop and asked them to take 20mm off the top of the steerer tube for a cleaner look, and they called me back and told me the steerer tube was cracked and the bike was F-ed. Upon inspection, I could see that there was a crack in the top of the steerer tube (see pictures below) but I think that this crack has been there since I got it used from a used bike swap as there is caked on, hardened grease in the damage, and a purposefully placed, well-fitted, steerer tube clamp spanning most of the length of the crack. I think I have ridden it several thousand miles since then, at high speeds, during crits, with no issues. I was pretty shocked to see that it had this damage that may have been there for a long time.

So my question is, do you think this bike is totally screwed? Replacement forks are nearly non-existent and the model is discontinued. Do tube plugs really reinforce the steering system to a point to where it is reliable and less likely to fail? I know nothing about these types of plugs.

(I obviously take all opinions as such and will then make my own decision).

Thanks for your thoughts… even though I bet in the end the answer is, “She’s screwed, Mate.”

Are you sure it’s a crack and not part of the mold? Tap test? What about having a real expert take a look?

If it’s really a crack that big and long then you shouldn’t ride it. I wouldn’t. Crazy to risk your face for that.

If the bike uses a standard headtube/headset then you could probably get an Enve or Ritchey or any other carbon fork. Paint won’t match but who cares for a race bike?

1 Like

No. The plug expands into the steerer tube, so puts pressure outwards. That can open, and cause cracks. It usually is ok because on the outside of the steerer tube, the stem puts compressive force on the steerer (overdoing the stem bolts can also crack the steerer tube). Both counter each other. (Most steerer failures come from the stem being clamped at a point where there is no inner plug, and then compressed too much).

The plug isn’t extra long, that’s a normal length for a carbon steerer plug. The purpose of the plug is to hold the top cap bolt, which pulls the headset together. In a metal steerer, a “star nut” is wedged in, but that would damage and put too much point load on the carbon steerer, so the longer carbon plug is used. The plug expands outwards, and has some sort of file-like rough surface, which grips the carbon steerer tube over a lager area.

With you fork, I think if you could take all of the cracked section off, you would be able to use it. But I don’t know if that’d make it too short for the frame and stem.

You could also talk to a carbon repeair expert. It might be possible to fit an insert to strengthen the whole section. You’d then need an extra slim steerer plug, but I don’t know if those exist.

Your fear should be the whole fork snapping off under the stem and you going down. Don’t ride it if it’s cracked.

IMO its cracked and dangerous.

Not my recommendation (not saying I wouldnt do it either) but take your 20mm off the steer tube and get the zin glue in. Use the proper strength epoxy and bond it to the steer tube.

Go on with your day, if it brakes with an aluminum epoxied insert and then happens to shear that, it was meant to be.


If I liked the frame, i’d probably just get a generic replacement fork.

There is no way I would ride a bike with that fork. Steerer tube failures are similar to e. g. handlebar failures lead to severe accidents. (Just imagine what could happen.)

Bikes have a finite lifespan. I suspect that if the bike is relatively old, it doesn’t make financial sense to have it fixed — if that is even possible. The crank is very long and wide.

I like the glue-in plug posted above. I’d talk to a carbon repair place and ask them what they think and if they can glue that in.

1 Like

I’m tempted to try out that zinn insert. I have a fork with a damaged fork where stem bolts clamp. Not a large clamp. I already have a replacement fork that somebody gave me. But I’d be curious to try this insert.

I watched the instruction video and of course it’s as simple as just roughing up the inside of the steerer tube and gluing it in place. The video made me laugh as the guy is not wearing gloves slathering epoxy over everything and constantly dropping the insert on the floor. lol not the most confidence inspiring video. Lol