Not So Fast!

My bike computer turned me into a superman with a maximum speed of 94.6 kph.

A month or so ago I bought a Cateye Micro Wireless Cyclocomputer (CC – MC100W). The reason for getting a wireless bike computer was that I was disgusted with the wire on the wired kind failing after a few months of use. The wire that connects the mount on the handlebars to the receiver on my fork tends to short out leaving me with a good bike computer head that is deaf to signals that should be coming from the sensor. I tried a wireless computer a few years ago and was very disappointed. It didn’t last even a single day. It didn’t mount securely to the handlebars and loosened from road vibration and fell off. I returned the thing to the store where I bought it and got a wired bike computer. After that I stuck with the wired kind. I suppose I am partly to blame for being a cheapskate and not paying top yen for a high end bike computer but I have always felt that either due to bad luck or just general clumsiness that buying expensive gadgets is a waste of money because I will inevitably break it. Well after a few years of using the wired type and replacing them every 6 months or so when the wires inevitably shorted out or the device failed for some other reason I broke down and spent the extra money to get a wireless cyclocomputer. I was ready to try wireless again after buying a used bike that came with a Cateye Micro Wireless Cyclocomputer. If the computer on that bike is to be believed it performed well for over 5,000 kilometers.

When I installed my new wireless bike computer I was ecstatic with the fact that there was no wire wrapped around my fork and stem nor tangled in my cable lines. Well my joy didn’t last long. Within a week I noticed that the cyclocomputer was returning an unbelievable number for my maximum speed. The first time I encountered this it showed that I had gone a maximum speed of 94 plus kilometers per hour! Even in my wildest dreams I don’t go that fast. Frankly, I would be scared to go that fast on a bike. The first time I experienced this I hoped it was just a fluke and ignored the problem. I really didn’t want to think there was something wrong with my brand new wireless bike computer. When it happened again a few days later I could no longer fool myself into thinking it was a fluke. The problem is that if one of the values displayed by the cyclocomputer is wrong it makes the other data points unreliable. I don’t really pay that much attention to my maximum speed compared to my average speed but I do pay a lot of attention to distance traveled and it bothered me that I couldn’t be sure if the number was correct. As the ersatz numbers began to reappear from time to time I started to consider what might be the cause. I got it in my mind that the receiver may be experiencing interference from some other source or that the battery in the transmitter on the fork or in the head was weak and needed to be replaced. The latter didn’t seem likely as the bike computer was still brand new and these kind of devices have very low power consumption. The former seemed the most likely so I began staking out my max speed rating to zero in on the culprit. The problem was that I never saw it register the false number. It never misbehaved while I was watching. The old adage “A watched pot never boils” applies here. I thought about all of the sources of radio transmissions that could throw the computer off and the only one that came to mind was railroad crossings. No matter which way I go on my commute there is always a railroad crossing. Nothing else came to mind. Unable to catch the culprit in the act and tired of the false readings I contacted  Cateye with my problem. Below is my correspondence with Jeff Wilbur from Cateye.

On Jul 9, 2010, at 3:58 AM, tokyotwowheeling wrote:

Dear Cateye,

I recently bought a Cateye Micro Wireless Cyclocomputer (CC – MC100W). I noticed that occasionally the data seems to be incorrect. It is especially noticeable with the Maximum Speed. Sometimes it is as high as 92 kph. I know I only go that fast in my dreams. Is there something that I can do to fix the problem?

Regards,
Paul Oertel

On 7/10/10 5:00 AM, service@cateye.com wrote:

Hi Paul
The unusual maximum speed readout that you are incurring is likely due to the cordless computer unit registering interference from an outside electrical field.  Sources of such fields include RR crossings, power lines, security systems, radio towers, home computers and wireless internet networks, televisions, radios, cell phones, garage door openers and invisible dog fences, high intensity discharge lighting systems, etc.    When all speed related functions are accurate EXCEPT max. speed, this is almost certainly the case, as wireless models manifest the reception of outside interference as an abnormal max. speed readout.   Unfortunately, there is no solution for this, as the FCC requires electronic devices such as bike computers to accept all such outside interference.

Best regards,

Jeff

1-800-5-CATEYE
service@cateye.com
www.cateye.com

Jeff from Cat Eye confirmed my suspicion about interference and tipped me off to other sources for signal noise. By coincidence I happen to have positively identified a source for my unwanted wireless noise. At the end of my ride I always take the cyclocomputer head off the mount to bring it in the house where I can record the data. As I passed the head over my iMac wireless mouse I noticed the transmission icon blinking and the maximum speed climbing up at a furious rate.

Based on this information I wanted to know if the erroneous data impacted the other data values. I put the question to Jeff at Cat Eye’s service . And here is his response:

On Jul 12, 2010, at 5:09 PM, tokyotwowheeling wrote:

Jeff,

Thank you for your quick reply. Do these outside fields also affect the DST, ODO and AVS values?

Regards,
Paul

On 7/10/10 5:00 AM, service@cateye.com wrote:

Hi Paul
The unusual maximum speed readout that you are incurring is likely due to the cordless computer unit registering interference from an outside electrical field.  Sources of such fields include RR crossings, power lines, security systems, radio towers, home computers and wireless internet networks, televisions, radios, cell phones, garage door openers and invisible dog fences, high intensity discharge lighting systems, etc.

When all speed related functions are accurate EXCEPT max. speed, this is almost certainly the case, as wireless models manifest the reception of outside interference as an abnormal max. speed readout.

Unfortunately, there is no solution for this, as the FCC requires electronic devices such as bike computers to accept all such outside interference.

Best regards,
Jeff

Once again I followed up with Jeff regarding my findings and this is what Cat Eye customer support had to say.

On 7/10/10 5:00 AM, service@cateye.com wrote:

Hi Paul

Thanks for the follow up and feedback about the interference issue.  I’ll be sure to keep your comments in mind when troubleshooting other future inquires of that nature.

Best regards,
Jeff

I’m glad to be of service and I hope Jeff passes the word on to his fellow support staff and to the engineers who designed the Cateye Micro Wireless Cyclocomputer (CC – MC100W). If you have one of these bike computers keep it way from your wireless mouse and