Aaron's Bicycle Repair will not do any work on any bike (not even a flat!) with visibly damaged carbon fiber.
Also, we will not work on repaired carbon fiber frames. Calfee is the only place we know of and recommend for carbon fiber repair.

If you have any carbon fiber parts on your bike read this article.

Trek Bicycles official warning about carbon fiber components, frames and forks.

And a very interesting article by Thompson about why they won't use carbon fiber.

Our 2007 crop of broken carbon fiber:

We will only sell components from the allowable list.
Allowable: Derailleurs Shift Levers Brake Levers Chainrings with aluminum teeth Bottom Bracket Shell Hub Center Shell Fork Legs (only) Seat Stays Dust Caps & Spacers (Headset, BB, Hub, etc) Carbon Fiber Handle Bar Tape (Yes, they make it!) Shoe Soles Helmets	Not Recommended: EVERYTHING ELSE! (including but not limited to): Handlebars Stems and Face Plates Seatposts Seats and Seat Rails Chainstays (on an aluminum frame) Drop-Outs (Frame & Fork Legs) Steerer Tubes Full Carbon Frames Cranks Chainrings with carbon teeth Hub Flanges Rims Spokes Brake Calipers Fenders & Water Bottle Cages (broken carbon is razor sharp!) Carbon Bolts

Here is what Lon Kennedy, owner of Nova Cycle Supply (a wholesale supplier of Columbus carbon forks) has to say:
From an email:

From: Lon Kennedy
To: Tech Info at Nova
Sent: Monday, January 28, 2008 9:47 AM
Subject: Re: Carbon Steer Tube Damage?

Aaron,

Given the pictures, and not the part itself, my opinion is that the steerer appears to have cracks that would make the fork unsuitable for use.

Possible reasons for failure generally fall into 2 categories. My explanations are general and since I do not have the part in front of me to make a specific determination, are for your reference.

Rupture failures

1) Placement of the expander cap in an area not constrained or supported on the circumference by the stem or overtightening the expander cap.
As you are probably aware, general correct assembly practice is to make sure that the expander itself is surrounded by the stem to support it and prevent rupture failures.

Perhaps, too many spacers?

Snakebite failures

2) The stem has some areas of contact that are not carefully deburred as part a correct assembly routine. If the slot or the top or bottom or the stem is not properly deburred a crack can be initiated by the non-deburred area (sharp edge) scoring the steerer tube and initiating a crack.

My opinion is that the fork is unsafe to use given the appearance of cracks.
Hopefully this will help you in your assessment.

Lon/NOVA

Below are the pictures of the fork discussed in the above email.

More pictures of failures.

Below is damage to a fork from SKS Race Blade fenders.
The damage is caused vibration and the dirt that gets under the mount.
Current Race Blade fenders come with clear plastic protective stickers. You can also use several layers of electrical tape.