I dropped my fork today as part of routine maintenance and saw a mark right about where the compression ring sits that I hadn’t noticed before. It is only present around a fifth to a quarter of the circumference of the tube but can be felt with a fingernail.
I’m pretty resigned to needing to get it checked out by someone but is this a) something any LBS worth its salt can safely diagnose and b) cause to stop riding immediately?
Do you have a set of vernier calipers to get a rearding on the depth Vs the rest of the steerer?
It does look like a ring of death, but I’d call it atypical in that it’s very narrow. I don’t think you need to stop riding it based on what I can see and the fact that it’s not full circumference, but it would be good to know how deep it is first.
I’ll try to pick some up and measure. Is there a rule of thumb for go/no go as far as depth?
If it isn’t already, it’s at least the start of one, I’m afraid.
Stop riding and search for the cause before it’s too late.
On a Geek Warning Episode with a carbon specialist, 0.3mm less than the steerer tube diameter was mentioned as the safe limit before repair is needed. Ball park figure that can be quickly checked at home.
You can see in the left side of the red box there is a clearer line above but a lighter line below. It is easier to see it in the silver part of the steerer.
At a minimum this is the beginning of a ROD.
I’m running a 70mm expander plug, and the top of the RoD notch is just beyond 70mm from the top of the steerer (stem is 40mm tall and 30mm spacers). I’m concerned, having re-listened to that geek warning with Raoul Leuscher, that my issue is frame alignment based, since I haven’t noticed any headset play in the couple of years that I’ve owned the bike (it was purchased used).
Does it seem likely that running fewer spacers, so the steerer is supported beyond the compression ring and bearing, would prevent this from recurring with a new fork?
Ohh, interesting. I don’t remember hearing that. Was it Raoul Luescher?
Yes it was. If I remember correctly Raoul said that while curing CF frames, differences in % shrinkage around the a CF frame’s head tube and the related bearing seats can result in misalignment and headsets not remaining sufficiently preloaded. He indicated that the ring of death is almost entirely an issue with totally integrated front ends on bikes.
Someone please correct me if I misremembered something from that episode.
I have what appears to be the start of ROD on a carbon steerer tube. Had it inspected by someone locally and was told it is fine. It is certainly less that 0.3 mm (actually significantly less that 0.1 mm) change in diameter, so knowing that Raoul Luescher said that gives me extra peace of mind.
It can happen on any bike when the fork isn’t tightened enough. I had it on a very much non integrated bike 
Personally, if I wasn’t 100% sure about something (especially rated to something as crucial as a fork) I would never advise to take the risk.
I contacted 3T support, they advised from that photo that it’s superficial so fine to keep riding. I think i recall someone else on discord getting the same response to a similar inquiry a while back. Still going to take it to a dealer to have someone (hopefully) with experience give an opinion, or at least figure out what is to be done.
Your point would be perfectly valid if I’d said something like: “It’s fine, just ride it”.
That seems kind of reckless to declare a non issue without even inspecting.
I had a ROD repaired on my Tarmac, I think he said of its <0.5mm change in diameter they will do a resin repair to make it round and flush, otherwise it’s a carbon repair / trash. It’s been fine since but because the resin is clear, the ring is still visible which give me a heart attack each time I pull out the fork.
Agreed that the blanket dismissal from 3t was kind of wild. I got the bike back from the dealer today, they inspected and said no issue to keep riding, just inspect it periodically and be vigilant about play.
I would have someone look at it person and not trust anyone judging the extent of the damage on a photo.
More importantly, you need to figure out why your fork steerer was damaged and take care of the underlying cause.
A couple of things:
If you want to continue riding the bike, I would immediately cut the 30mm of spacers (which—why?!) and make sure you then have the entirety of the stem fully reinforced. Hard to see much going bad with the compression plug backing it up (at worse maybe a sound indicating carbon breakage rather than the stem outright breaking off?).
The response from 3T is about the same response you’ll get from anyone who isn’t on an EC podcast or in the carbon fiber repair industry. I’ve replaced probably 3 forks once I’ve seen that type of ring. Every time I’ve had very good, very highly regarded mechanics and/or shop workers tell me I’m totally fine and they’ve “seen much worse.” Do with that what you will, and make a decision based on your own personal comfort level.
I’d do the same.
Not exactly the same thing, but I have lost my Garmin Varia about a month ago. I know that once I order a new radar (I’m going to try Wahoo’s radar as it gets better battery life), I will find the Varia. But safety >> saving 200 €. I commute to and from work by bike.
