2 Bicycle Bike Tyre Wheel Flash LED Valve Stem Cap Light Blue

When these first arrived I thought the batteries were dead. It was when I opened them up to see what kind of batteries they needed that I discovered the little pieces of paper meant to keep the batteries from going dead during shipping or sitting on a store shelf. Once removed, the lights worked great! They attract a lot of attention when I'm out riding at night and I've been asked about them a lot. I will say the photo in the listing is a bit misleading - you have to be going VERY fast for them to look like a blue ring of light on your tire. This is true of all wheel lights though, so just a heads up about that. Also, if you screw them too far down on the valve stem threads you may inadvertently cause your tire to go flat over night as they can put just enough pressure on the stem to slowly leak air. No problem, I pumped the tire back up and didn't screw them on as tight. Since then, they've given me no problems and like I mentioned before, people really notice them. I like them!

For under $2, they are very bright. All you have to do is unscrew the case, take out the paper seal (very easy), and screw it back on. It is activated by motion. When stopped, they are off. The batteries last a while too, have had them for over 3 months, and haven't had to replace them.UPDATE 05/26/15After ordering 6 more pairs of these, I realized that there is a percentage of them that don't work. About 1/4 to 1/3 don't work as well as they're supposed to. I still don't see a problem with this though, as 6 pairs was only $9.40. Out of the 12 that I received, 9 work to their full potential.

The photo of the circle of light is completely misleading, but par for the course for any of this type of light. Still, it does certainly make you more visible with, than without (duh!). The most disappointing aspect is that when you are stationary (say at an intersection) the (motion activated) lights go dark. This leaves you pretty invisible from a broadside hit - unless you have a headlight and a tail light that also push light off to the sides. Possibly because the lights go dark after a few seconds of being immobile, the batteries last a long time.These lights made a nice ADDITION to your bike, but should NEVER be relied upon as the only source of light.

When I tried it for the first time I was spinning the wheel like a mad man at my house and it was working but when I went out after a few minutes the light turned really weak and just stopped entirely. After this it didn't light up even at 50+ Km/h. I disassembled it and figured out that the motion sensor part was working fine the problem was at the other leg of the LED. It turns out it failed to give contact always, as it should. So I tried a few things and surprisingly after taping together the batteries it started working like a charm. Since then I had no problems with it.

So far, they are working as they should! It was a bit hard figuring out how to assemble them at first...you have to remove the paper in between the batteries and then align the batteries a certain way. I had a bit of trouble fastening them to the spokes, but now they are on. They light up the tires as the picture shows! One issue is that they light up even in the daytime (no way to turn them off), so I'm not sure if that will drain the batteries in the long run?

They get the job done. I like to ride my bicycle to the gym and sometimes I get a little carried away at the gym or being with a friendly conversation with someone andit causes me to have to ride 5 miles back home near dusk, down a dark commute. I do have an internal hub as well as bicycle frame lights and a light on the handle bars.These are great because they come on whenever I ride and It slows on looking drivers when my hub light and these stems crank up.

Meh. Were cheap, so I did not expect much. But the suggestion in the description is that they are motion powered, but they are actually powered by a watch battery. In addition, they don't fit well onto valve stems -- the screw-on depth is inadequate, so if you screw them on tight, as you would certainly want to, they depress the valve pin slightly and let air out of the tires very slowly. The screw mount thread needs at least another eighth or even a quarter inch of depth.

Solo pude conectar uno ya que no llegó completo, faltó un conector

okay, however sometimes it lights up and sometime not!

They work great, my only problem is that the valves pert rude from my wheelchair wheels and the plastic tip breaks off if I get too close of anything if the tip was a flexible plastic it be better, I realize that these are disingenuous more for a bike spoked wheel than a mag wheel such of what I have The ones I tried were multi coloured red, blue, green & yellow. These were just blue which I was OK with.

nice little flash, just a little difficult , removing (figuring) the battery stopper, centre part un-screws, remove square piece of paper, motion detectionactivated

Thought they would be durable since they'd be attached to my wheels and exposed to the elements but they were made of shanty plastic and barely lit up when I pulled the tab for the batteries. I wouldn't recommend these to anyone.

ne fonctionne pas bien...Allume pas toujours lorsque je roule.Bout et vis en plastique fragile.