Road Cycling - CArbon fork question... was my club rider friend messing with me ?

So I was out on a 22 miler after work last night with my club, and I noticd that whenever I hit the front brake I could hear a click-click-click noise... I rode for about 10 miles like this and it was driving me up the wall.. I ask my buddy I'm riding with, and he says it is probably the magnet for my computer hitting the sensor... I looked, and as a matter of fact it was. I tried to adjust it on the road, but didn't make it any better.

And here is where I am perplexed.

It only happens when I hit the brake. My riding buddy says this is, "It happens because the carbon fork flexes a bit when you hit the brakes causing the two parts to collide." (I believe this) Then he goes on to say, "Usually the fork will flex more before it is about to completely implode." I thought he was just messing with me.. but When I asked him, "Really ?" He relied with, "Yep!" And since this has never happened before, it left be a bit bothered.

Now he has a very dry sense of humor... like Sahara desert dry... so I'm not sure if he's pulling my leg, or serious... What do ya'll think ?

Lemme know-- the fork is only a few years old... it was used when I bought it, appears to be in good shape, and I've put about 1500 miles on it in the year since I've owned it...

Lemme know

Jeff

It only happens when I hit the brake. My riding buddy says this is, "It happens because the carbon fork flexes a bit when you hit the brakes causing the two parts to collide." (I believe this) Then he goes on to say, "Usually the fork will flex more before it is about to completely implode." I thought he was just messing with me.. but When I asked him, "Really ?" He relied with, "Yep!" And since this has never happened before, it left be a bit bothered.

I think he could be right but you need to do some followup checking. All forks flex a little and if the arc of the magnet is normally close enough to the sensor, that may be enough to cause some impact. While it's true that in most cases, CF will just catastrophically fail without warning due to a crack, it's not always the case. Carbon fibre components can exhibit a little more flex before failure when they delaminate or some of the internal fibres break and you lose strength in a particular direction. Remember the chainstay on Lance Armstrong's bike after the crash with the bag in last year's TdF? I regularly do an electrical resistance test on my bike using strategic test points to act as a sentinel survey of health. You might want to have your fork inspected if you're really worried.

Does one side of the brake shoe contact the rim before the other? If so, the pressure from one side may be pushing/flexing the wheel. Make sure the brake shoes contact the rim simultaneously.

1500 miles is nothing. If there is nothing wrong with the fork and it's just the seed of doubt planted by your friend, I would not worry about it.

Is the headset tight?

Make sure the headset is tight.

Dismount the bike and apply the front brake and move the bike forward. See what is happening.

Thanks all for the tips.. I feel much better about it all now. I will check all that stuff out tonite and see what is happening... I just couldn;t believe that my fork was ready to explode on me just yet... it still appear to be in good shape otherwise

thanks all

Jeff