I have an Argon18 Platinum, which has a Argon18 branded carbon steerer fork. The stem used is a Ritchey Al stem. The stem/fork combo was installed on the new frame by the LBS (very competent mechanics) and has, until the last week, given no problem in about 12,000k of racing and training.

I noticed that when I stand up on the pedals, and so go from seated to standing, I could feel a bit of a clunk in the front end. If I flex the bars (say from the shifters) there was a bit of flex that either was not there before or I had not noticed it.

I took the stem off - for the first time - and noticed there was an imprint on the front of the steerer. The imprint matches the inside front side surface of steerer part of the stem - the . It is a roughly circular shape.

I took the bike to another LBS - also very good mechanics, and also an Argon dealer - to ask them to have a quick look and see whether it is worth taking the bike to the LBS that sold me the bike, stem and built the bike up. The selling LBS is not as close to work. The other LBS is concerned about the marks on the stem. We looked at my stem and the inside surface of the steerer clamp part of the stem has quite sharp edges. We looked at a whole range of other stems and there is a wide variety of surface areas and "sharpness".

The steerer has no cracks, and is otherwise in excellent condition. The headset was not "loose" at any stage.

My questions are:

1. Are marks like the one I have described normal or something to worry about?

2. Can they be repaired?

Thanks

The LBS I purchased the frame from will look at the bike, but commented that such marks (as I described it)

If it's not cracked, I wouldn't worry about it. The impression, according to Calfee (custom stem/bar part of the webs is bad, at least long term.) I don't know how much credence to put in that, in terms of using the part, as opposed to building up a custom combo with a used part that is imprinted. Notify (show them) the LBS that they may have overtightened the stem and inspect it for cracks on a semi regular basis. It should be fine, but if not you've already notified the LBS that there was a problem with their installation.

if you're feelin' a clunk odds are that your headset bearings are loose. try tightening them up first.

if you're feelin' a clunk odds are that your headset bearings are loose. try tightening them up first.
That was my 1st thought - an improperly adjusted headset.

Vendor LBS looked at it - the wear is to a cosmetic layer, and caused by sharp edges on the stem. LBS replaced, at no cost, the stem with a 3T stem that has more internal surface on the steerer interface. Will keep an eye on it. So far so good.

With regards to tightening a carbon steerer, is there a torque specification?

If so, is it specific to each model?


Any references to this info appreciated.