# EVO FORKS - Carbon steerer tube wear.



## cooldollar (Jun 4, 2012)

Hi All
I am wondering if any of you mechanics out there have experienced this.
I have an Evo Hi-Mod. The steel headset compression split ring has a razor sharp edge on the inside. As a result of this compression on the carbon steerer tube the steel ring has worn a lovely groove around the carbon steerer. Steel hard - Carbon soft = wear
Before everyone chimes in with a reason why let me explain the headset was not allowed to get loose, and was never overtightened. It is not until complete disassembly that the damage can be seen.
This is now an unusable fork for the time being due to safety concerns regarding potential breakage under severe handlebar load.
I have seen this on several Evo's but this is the most extreme damage.
Your thoughts?


----------



## goodboyr (Apr 19, 2006)

I will inspect an EVO himod in our group to see if the same thing has occurred and report back. I can tell you that the headset on this bike was very difficult to get right. I needed to add several micro shims so that the frame didnt interfere with the correct setting of the preload on the headset. Without the shims, it would tighten down, but not put sufficient preload on the bearings and the headset would remain loose. You may want to check that.


----------



## Dan Gerous (Mar 28, 2005)

I have seen the compression ring kind of polishing steerers but not wearing into it like that. My first guess was it's overtightened, but... Was the ring hard to slide onto the steerer? It should be snug but still easy to slide it down.

Good idea to check goodboyr's suggestion that it 'could' be that the frame stops the preload you can put... but if it was the case, the compression ring would not be too tight but too loose so I'm not sure it could do such damage... unless the wear is from some play so the steerer and ring can rock into each other constantly, but then I'd think you'd feel the looseness.


----------



## macca33 (Oct 24, 2012)

Wow - not cool at all.

I have 2 x CAAD10s with carbon steerers and have never seen this - usually pull the headset to re-grease twice a year.

I reckon it may have been overtightened myself - but it is difficult to say from pics alone.

cheers


----------



## robt57 (Jul 23, 2011)

If you had not said it was not overtightened, this is exactly what I would have suggested. Why it that piece rotating with the the bearing and not on the steerer?
Or do you think it may be from rocking from sprinting forces and steerer flex maybe?

Shows the importance of the inspections to be sure!


----------



## bt100 (Jul 18, 2011)

Hey I've got the same issue. My bike is in the shop now and the latest is they can't find a matching fork. Mine is a 2012 supersix evo


----------



## edechols (Jun 5, 2018)

This is from my 2012 Trek Madone 5.2. Same groove and about the same size. Could this be a bearing or bushing issue?


----------



## cooldollar (Jun 4, 2012)

That is exactly the same problem. The aluminium spacer wedge (silver ring in my photo above) has worn a groove around the steerer tube. Depending on the thickness of the carbon steerer tube this could be the end of those forks. Darn it !!!


----------



## scooterman (Apr 15, 2006)

Just assembled a caad12 disc frameset and it had a plastic compression ring.
I can check my 2018 evo and 2018 superx too.

I have seen this before, mostly on loose headsets i think. The worst i saw was on a Focus that the person basically always rode with a loose headset.


----------



## SC_CarbonRepairs (1 mo ago)

Essentially what is happening is the headset may not be loose, but the correct compression assembly is comprimised. It all boils down to the compression insert at the top of the steerer. As you hit heavy bumps/potholes, your stem is underload thus deforming the steerer. When this happens the stem acts as a lever on the top cap forcing the compression insert upwards creating "play" in the headset. This will then allow that little split ring to cause the wear that is shown in the picture. A subsequent issue can arrise as the bike owner is sick of their headset coming loose so then over torques the stem crushing and cracking the steerer. I know I know. I hear you say, "My headset is never loose". It has about as much credibility as bringing a cashed bike in six pieces into a store and trying to convince them you were just riding along and it fell apart. I have repaired a tonne of these forks and soon I figured out the issue. I have worked for a number of cervelo dealers where they neglected to use the "glue in" insert that has a starnut inside. I graciously asked for them all as they were taking up realestate. I now install these as part of the fork repair and I have never had one back. I can tell you now, either in your current bike or new one if internal cabling allows, find one of these inserts in install it. This will prevent all this from happening.


----------

