Got an XT-E drop-in today; first impressions of it and the LED.

[orbital]

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RedForest, you should not have said where you got it,, and instead said you spent $120 for it.


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[Mike S]

Another myth. It is not color separation. It is the fact that at that angle the light is going through a larger cross-section of phosphor.

Right, I understand why it happens, but "color separation" is the term that I see used quite a bit on the various lighting forums when referring to that tint shift.

What's the more correct term for it?

 

[qwertyydude]

I don't think anyone who says the XM-L isn't suited for bicycle lighting actually ride a bicycle at night. It's ideally suited for bicycling.

Read all over the mtbr forums and people complain day in and day out that regular led lights are too throwy with traditional flashlight reflectors. Most of the budget bike lights are simply converted flashlight heads with a separate power brick. But having a narrow bright beam makes riding at night on bike trails dangerous, you can't see what's off to the side and you end up with basically tunnel vision.

What you should ideally emulate is motorcycle headlights. These have a beam that goes out but also speads out a decent amount, not a pencil beam, they also have a generous spill, it's much like a car headlight. And the XM-L in a small reflector like a P60 does pretty much this, albeit with more glare toward on-coming traffic. But riding a mountain bike that's not that important. And there's absolutely no need for 1000 lumens like that on a road bike riding in the city so the glare problem is moot.

 

[Blitzwing]

Gotta agree qwerty. An XML on the bar and one of the helmet is good.

 

[A10K]

People really misread my post, that's all I'll say. I use an XM-L for some of my night riding.

My XT-E drop-in has also arrived, its a 3-mode like the OP's, driven at about 1A based on tailcap measurements (using CREE's product comparison tool this comes out to about 370 emitter lumens, guessing around 300 OTF). Part of the hotspot and outer spill is cool white, but the corona and center of the hotspot have significant yellow artifacts in them. I can actually get the center of the hotspot to form an "X" depending on the focus, meaning that the LED projects an image of the "X" from the die. Its noticeable on white walls, smooth concrete, and clean asphalt. Against grass, vegetation, or urban visual noise, its not a significant issue and the beam appears cool white. I threw it on my bike for a little bit of street riding and I think the throw/spread is decent for that application, though I don't have any XP-G drop-ins to directly compare to (Hi-CRI isn't in the same ballpark output-wise).

 

[sportyaccordy]

I don't think anyone who says the XM-L isn't suited for bicycle lighting actually ride a bicycle at night. It's ideally suited for bicycling.

Read all over the mtbr forums and people complain day in and day out that regular led lights are too throwy with traditional flashlight reflectors. Most of the budget bike lights are simply converted flashlight heads with a separate power brick. But having a narrow bright beam makes riding at night on bike trails dangerous, you can't see what's off to the side and you end up with basically tunnel vision.

What you should ideally emulate is motorcycle headlights. These have a beam that goes out but also speads out a decent amount, not a pencil beam, they also have a generous spill, it's much like a car headlight. And the XM-L in a small reflector like a P60 does pretty much this, albeit with more glare toward on-coming traffic. But riding a mountain bike that's not that important. And there's absolutely no need for 1000 lumens like that on a road bike riding in the city so the glare problem is moot.

Motorcycle headlights are designed to the same standards as car headlights... they often share components (Hella projectors for example)

Problem I am finding with LEDs, at least in traditional configurations, is that they are terrible with spill because of their angular falloff. A motorcycle/car headlight takes light from a point source and redistributes it through a shield and parabolic reflector, giving it spread + throw... a typical LED or even an LED array is just a spotlight

For bike riding where speeds are low I think a regular LED is probably good enough. Even the glare is OK, as you want to be seen. But if you really want that wide beam like a new DOT headlight you will definitely need some sophisticated optics. Even an LED in the place of an old filament would not work well.