I took some new lights out for a test ride last night. I mounted Cygolite's Trion to the left of the stem, and a P-Rocket Cree XP-G R5 450 from ShiningBeam to the right of my wireless Cateye. Here's a grainy, fuzzy picture of the layout...



When the Trion was on, the Cateye stopped working. Like it wasn't getting a signal, and basically behaved like the bike wasn't moving. I guess the Trion creates some sort of interference. When the P-Rocket was on, the Cateye ticked along happily, despite being even closer together. I'm guessing this is a power supply issue? The P-Rocket is just running on an 18650, but the Trion has some sort of proprietary built-in battery.

I could probably address this by getting a wired Cateye, but the light from the Trion -- though basically working pretty much as advertised -- didn't impress me enough to justify the extra expense, so back to Amazon it goes. I'm looking for something to get me down dark mountain descents (road, not MTB), and the Trion's soft flood didn't do much for me. The P-Rocket was pretty good, and the spot was more conducive to highlighting road hazards, but I think I'll go back to Shiningbeam and look for a brighter light to use as my primary.

Anybody else ever have problems with a light jamming signals for a wireless computer?

Or get a digital wireless computer or GPS. This is a common problem with analog wireless computers and LED/HID lights. On a different note, I agree about soft flood beams not being very good for road use. Too much light too close to the bike makes it hard to see what's several seconds out. The Trion would be more in its element on a mountain bike.

Yeah, I should get a GPS, but I've been lagging on that, partially because I'm not totally confident that it'll get a signal up in the mountains where I ride. If the Trion had really impressed me, I might have been compelled to take the plunge, but like I mentioned, I didn't end up liking the light enough to justify any extra expense.

On the other hand, I know nothing about digital wireless computers vs analog. Maybe that is something I should look into, assuming the price point is comparable. BUT... good to know that this is a common problem with analog wireless and LED lights.

For now, I expect to be happy just swapping the $210 Trion for a $40 flashlight.

Yes. LED lights have a highly efficient regulator circuit that creates low level radio interference. Analog wireless cyclometers are often susceptible to this interference. Wired, or wireless ANT+ cyclometers are not.

The Cygolite engineer is there. Just give them a call. Also ask them about the Trion and maybe they will have an answer for you. Just tell them what you experienced.

In the words of my Electromagnetic Fields professor, "Say what now?" GPS satellites orbit at a height of approximately 12,600 miles. If you're in the mountains, you will have shaved 1-6 miles off that distance, peanuts in the grand scheme of things. If you were riding in mountainous caves, you might see a loss of signal; otherwise, you'll be fine.

Yes. Niterider cordless lights do this too.

Here's the incredibly unscientific, uninformed basis for my concern...

A) My cell phone is dead as Dillinger up in those mountains.

B) I once overheard somebody who works up in said mountains tell a visitor that no cell phones or GPS devices work in the area.

And that, my friends, has been enough for me to hesitate to drop hundreds of dollars on a Garmin, especially since the mountains is where I do most of my riding. I will happily listen to reason, if others haven't had any problems.

I think that person meant cell phones won't work in the mountains including any GPS capability those cell phones have. I don't know why, but the GPS on my iPhone won't work if there isn't a working cell signal. My Garmin 500 has worked everywhere, though.

I don't think phone are using "native" GPS - in other words they take GPS signals that are rebroadcast from cell towers - not directly from satellites.

But how would I know?

Richard is dead on here. Cell phones have two different types of GPS technology. One is called Agps .... which relies on cell phone triangulation for location. The other type of gps is the space satellite kind which hypothetically should give you coverage from most places .... if your in the USA. Now having said that .... there may be places that satellites simply do not cross that often. If that mountain is one of them AND there are no cell phone towers ... then you may be out of luck.

Not all phones have both Agps and satellite gps. Though, most newer smart phones do. If you have an android device you can see what it says in settings. For instance the Droid Incredible has both.

total BS. Satellites are completely agnostic of any geographic location.

I stand corrected.

GPS satellite "orbits are arranged so that at any time, anywhere on Earth, there are at least four satellites "visible" in the sky."
- https://electronics.howstuffworks.com...travel/gps.htm

Which I did not know.

Thanks so graciously for correcting me.