Hello. I recently bought a Specialized Allez Pro with a carbon fiber fork. When I installed my Sigma Sport computer on the fork, I found that every time the wheel magnet tripped the sensor, the little "click" noise the sensor switch makes was amplified (powerfully!) by the fork. It was really loud! I've had no success isolating the sensor with cut-up inner tubes in between sensor and fork.

This wasn't a problem with my last bike's steel fork. Obviously, the carbon fiber makes a nice resonating chamber, where the steel did not--I never noticed the almost-inaudible sound before.

Has anyone else experienced this problem? And do you have solutions? I don't have another non-SigmaSport computer to try out, so I wonder if other brands don't have the noticeable click.

Thanks for your help.

Yeah, CF tends to turn your bike into a nice loudspeaker housing. Decreaking and sound-short removal is a common ritual amongst owners of CF frames.

Are you sure the magnet isn't striking the sensor?

Strange, I've got a Topeak Comp-150 wireless computer in conjunction with a Weyless carbon fork and have never once heard any noise from this setup. Make sure your sensor to magnet gap is close (2-4mm) but not striking it. This is a new one on me....

Yeah, it's definitely not that. I pulled the whole thing off the bike and tested it. I can hear the smallest "click" from the sensor when I wave the magnet near it. Not sure what's in the sensor, but whatever variety of switch it is, it goes click when it's tripped. The fork just picks it up and amplifies

There might be no good solution here. Maybe other brands of computers don't have the same sound, like the Topeak you mention, because of a different kind of sensor mechanism? I'll have to ask some friends to let me stick my head next to the whirring spokes for a listen.

Thanks to all for quick replies.

I have a Sigma Sport BC800 wireless & I also hear the clicking sound. The transmitter is mounted on a CF fork. I have never been bothered by the clicking sound though. Since I started using my L&M HID headlight, it interfered with the wireless operation. I have since switched to a wired mount. The clicking is still there.

Yes my cats eye also clicks when the magnet passes the pick up, though this can hardly be heard on the road iv put a piece of cotton 't' shirt under the pickup, the fork is alloy .A bees d!ck woudnt fit between the two,though there not touching

From the description given, the sensor would contain a reed switch. These are extremely simple magnetically activated electrical switches. They can be very small. They are also used in some security setups where a movement that is unwanted causes a magnetic field to either close the switch or open the switch (depending on the type of logic being used). Generally they are silent. I have been able to here some of the larger ones activate and deactivate. It's most likely that you just happen to have one that is making a small noise as it is magnetically closed and opened. The next ten people with the same computer might not hear anything at all.

I have a Specialized Allez sport and the same thing happened to me. I find when I stand on hills to power up them I get the clicking. I found it was the radial spokes allow a LOT of side to side movement which makes it hit the sensor post. I HATE the wheels that came with it. junk.

Thanks, all, for your help. Turns out it's not a problem at all on the road, as someone suggested. It's loud at home, annoying on the workstand, and not a bit noticeable with some wind in my ears.