Bike Lights: (Almost) Everything You Need to Know

We ask bike light designer Tom Place how bike lights work, and how we can get the most out of our setup for night riding.

Tom Place is the co-owner and head of Product Development for Outbound Lighting ( He’s a former Cree LED manager and holds multiple LED chip design patents.

In this episode, we ask Tom to fill us in on how bike lights work, and how we can get the most out of our setup for night riding.

  • What is the ideal beam shape for trail riding? Are certain beam patterns better than others depending on where you ride (eg. wide open desert vs. thick forest)?
  • How does light placement affect the beam shape?
  • What’s the theory behind helmet vs. bar mounted lights? If you only have one light, is it better to be on the bars or the helmet?
  • Can brightness make up for an inefficient or poor beam shape?
  • Why shouldn’t buyers focus on lumen numbers? Which features can buyers look at to compare bike lights?
  • How do you determine the optimal battery size for a bike light? 
  • Why do LED lights produce so much waste heat? Is there better tech on the horizon?
  • What could cause a poorly designed or manufactured light to pose a safety risk?
  • Do you have any tips for night riding?

A full, automatically-generated transcript of this podcast conversation is available to Singletracks supporters.

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Jeff 0:00
Hey everybody, welcome to the Singletracks podcast. My name is Jeff. And today my guest is Tom Place. Tom is the co-owner and head of product development for outbound lighting. He’s a former Cree LED manager and holds multiple LED chip design patents. Thanks for joining us, Tom.

Tom 0:18
Happy to be here.

Jeff 0:20
So tell us a little bit about your professional background sounds like you’ve been working with lights and LEDs for a while now.

Tom 0:28
Yeah, I grew up with a lot of lighting in my life, because my my dad did a lot of daylighting research as a professor, but professionally started in 2011, at Cree major led manufacturer in Durham, North Carolina, worked in the LED chip design, fabrication side of the business, and then moved into running our global applications engineering team where we had a lab where he basically took in new products from big customers, GE, Panasonic. So on that were kind of pushing the envelope with either new optical technology or new construction methods, and they’d run into issues. So they would send it to us to basically put it through testing and figure out what is what we could do to improve it. And so we would take it, measure it, make some modifications, re measure it, and then send the results back and basically give them guidance on Alright, if you use this different led package design, or if you use this thermal interface material, or this optic construction, we can improve XYZ by whatever percent. And it was cool because it it really gave me a lot of insight into the whole systems engineering approach where it’s not just an LED and an optic, there’s, you know, the thermal interface material, the PCB stack up electrical noise from parts of the circuit, the ceiling of the the total package and got to see a lot of really unique problems, which sets me up pretty well to, you know, not run into those same problems in my design process. Try college. And then from there, I had an opportunity to get into bike lights and kind of jumped on it because the rest of my personal time and livelihood is tied to riding a bike.

Jeff 2:20
Yeah. Interesting. Yeah. I mean, it sounds like you have a real technical background and understanding of lights and Cree. I mean, that’s, that’s kind of the biggest name and LEDs for a lot of applications. And especially bike lights, right, like a lot of bike light companies are using those Cree bulbs and LEDs in their designs, right?

Tom 2:41
Yeah, and Cree really made a name for itself in the portable lighting market. Because some of the sales guys way back in the day, we’d get on like candlepower forums and stuff. And Haley ds. And for the start of the company, they had a big leg up and everybody else because they use silicon carbide to grow their their epi further LEDs, and it was significantly more efficient than sapphire as a growth substrate. So people don’t need to do all this at any rate, they’re more efficient than anybody else in the market for many, many years. And other other companies like matcha and Osram couldn’t compete because they just weren’t efficient, because they didn’t have a silicon carbide substrate to start with. Now, everything’s kind of at parity. So it’s more an application based thing where cost and size come into it more than just raw efficiency. But yeah, they pretty much every portable lighting device you pick up is up until the past two or three years has been almost entirely Korean or fake Cree parts from

Jeff 3:50
Interesting yeah, I mean, they certainly built like a brand name to people who who dig in even just a little bit right you know, sort of like computers back in the day you know, like the Intel part and so yeah, when people were buying a bike like I mean a lot of the bike like companies they advertise that as like we use Cree bulbs. Yeah, which is interesting.

Tom 4:11
They have to actually vet that to prove that they are using Cree LEDs genuine product in order to be able to put that label on the box because they’ve had some some products before I mentioned the fake LEDs were company called lattice was making clone parts that looked identical and selling this flashlight company so they could pay less but sort of say three LEDs and yeah, well yeah, it’s there’s always something

Jeff 4:38
Interesting. So I mean, obviously LEDs are used in a number of applications and different products. So for you personally, like you mentioned, you know, you’re interested in mountain biking but like seriously why mountain bike lights like isn’t night riding sort of like a niche within a niche like it’s not it’s not a huge market compared to like other things.

Tom 5:00
No, but it’s also one that has not had a lot of focus on it. There’s there’s opportunity to make something better here. So, me personally, it was a natural fit, because I’ve just, it’s my two biggest passions in life. And so if I can make those work professionally, then absolutely, I want to do that. But my partner Matt, who’s the founder of outbound, he’s the one who actually started this. And the reason he did is because he’s a, he’s an automotive guy, he races rally cars, and used to work for diode dynamics and knows automotive lighting really well, when free trail ride with a buddy of his and his buddy gave him a couple, I think a remote writer lights at the time and went out for a ride. And he was like, Really, this is the industry has the offer this cost, how much what? And he thought, you know, I could do something better at a more reasonable price. And he did. So I reached out to him because he was actually doing something novel with the optical design and not just, you know, making another flashlight that was rebranded who’s doing something different.

Jeff 6:13
Yeah, interesting. Well, yeah, I mean, thinking about the different applications. You mentioned your partner came from the automotive world where Imagine you want your lights to, you know, your beam pattern to be a specific shape. And, you know, you’re, you have certain things you’re looking for at night, like what’s the ideal beam shape, then for trail riding. And then like, how is it different from maybe other things people might be trying to light up?

Tom 6:40
Sure. And it’s, it’s all application dependent, right. So like, the light bulb in your house is good for lighting up your room, because it’s omnidirectional, just casting light in all, all directions, and it’s not focused, you try to use that on the trail, you’ll blind yourself and you won’t be able to see very far because it’s not focused anywhere. On the other hand, if you take a really narrow beam, like a search light that people use out and out in the woods that projects three miles, now you can see that one tiny spot really well, and you can’t see anything else. So that’s not good either. And this is where you know, bike lights, to date, haven’t really there with a few exceptions haven’t really put focus on on optimizing that beam shape for the intended task. So for, for trail riding, it kind of comes down to where the light is gonna be mounted, as well, it’s not just one beam shape for everything. I’d say that in general, you know, for handlebar light, you aren’t always turning the bars where you need to be looking, you know, your counter staring into a corner, or just on a technical climb, your bars move around a lot. And if you have a narrow beam line on your bars, the moment you term, just a hair, that beam is now off the trail. So your bright spot is off the trail, so the trail looks darker. And then if you’ve got, you know, leaves or branches off the side of the trail that are closer to you, and you’ve got this bright reflection off of that. So you’re getting this kind of flashing effect, and it makes it harder to find the trail. So for bar light, we think it’s just, it’s just a lot better to have a really wide beam side to side. And then because we know that handlebars on bikes are going to be roughly the same distance from from the ground, you know, suspension dependent, but it’s going to be about three feet or so we can, we can tie that into our, our simulation or design so that when your light is mounted that height pointing straight out, you get a nice even covering on the ground in front of you, because you don’t want a hotspot right in front of your wheel, you also don’t want it to be dark, you’re gonna be able to see that out of your periphery. So having something that’s really wide and even, I think is important on the bars, whether it’s ours or somebody else’s. With a helmet light, you can get away with a bit narrower beam because you’re pointing your helmet where you’re looking. So you need to have the entire field of view covered because you’re controlling it much more directly. Still, though, having something that has a gentle fall off, or a smooth gradient from the spot in the center to the edges is important, mainly so that you don’t have as many distractions on the trail because if you’re writing, you’re want to be focusing on the feature in front of you not positioning this perfectly shaped circle of light, right where you need it to be. You want to just focus on the writing and if you have this circle or a hard edge or any weird beam artifacts that tends to be distracting, and it gets in your head and that’s not great.

Jeff 9:37
Yeah, does like the trail itself kind of dictate that too? Where I ride, there’s thick forests and you’ve got a lot of trees and things that are like, right in your periphery versus writing somewhere like the desert, let’s say where it’s like a really open, like do those both kind of need the same beam pattern or would there maybe be a diffrent need there?

Tom 10:02
It’s entirely so I found those when I was talking to somebody about this the other day. I say it depends a lot.

Jeff 10:10
Because it does. This the world we live in.

Tom 10:13
The marketing side of me wants to say, No, this is the perfect answer. But all of this depends. So, to your point, though, like I used to live in the Phoenix Valley in the desert, and oftentimes I would ride with just a handlebar light for two reasons. One, because the trails were all just sharp rocks is really rough. So the handlebar light gives you gives you depth that you don’t get from a helmet light because it’s mounted lower, so it cast shadows out that you can look down into so that rock sticking out of the ground looks like it’s actually sticking out of the ground and doesn’t flood lights by themselves make trails look very flat because the lights above your eyeline. But the desert also is very wide and open. It doesn’t have trees, you know, there’s cacti, but there’s not trees and branches and leaves covering every corner. So with a wide beam on handlebars, even if it’s a tight switchback, I can still see it extremely well, because you can get away without a helmet light. On the other hand, you know, like I’m in Pacific Northwest, it’s gonna be very similar to the type of riding you have. If you’re in thick forest, a lot of us switchbacks are covered. And handlebar light by itself doesn’t always cut it, there’s still a lot of value or may end of our light. But supplementing with a helmet light helps. And then the other extreme of that actually would be people like talking to clay Harper at the US Open Fox US Open, he goes out with his son and they hit like 30 foot booters at night. And you know, for that handlebar light doesn’t really do much of any good because you’re going up in the air and your bike is not pointed at the landing, right? Also, those jumps tend to be really smooth and buff, you don’t need to read three dimensional terrain because you know, the takeoff is going to be smooth, right? So for doing jumps, like helmet light by itself is is the way to go. Because you’re you really need to speed up your landings and you’re not having to read rough terrain as much. So it’s really horses for courses.

Jeff 12:18
You kind of kind of hit a number of the questions that I had in terms of like, the light placement and how that affects the beam shape. And, you know, it sounds like to I was, I was gonna ask you, you know, if you only had one light, would you rather mounted on the bars or the helmet? But clearly, you’re gonna say it depends, because it really does. And I understand now though, like, why it depends. And yeah, those are great examples. Like, you know, I was thinking about, like, really steep trails. And that’s kind of that same example with the, you know, riding jumps at night where, hey, helmet mounted lights gonna be best for that. Whereas maybe if you’re in a more open area you can get away with, with bar lights. So yeah, I guess it just depends.

Tom 13:07
And that steep examples, like, all of my trails around here are steep, you know, you roll up to an edge, and you drop into something into a shoot into whatever. And you’re right, leading up to that the bar light tells you, hey, there’s something steep coming up. To help feed down into it, but then once you’re into it, having the handlebar light helps. So it’s, it’s not just a, you know, there’s some, you know, jump lines may be the one example where the Hanalei by itself is always best. But on most trails, having both is usually the right answer. Yeah. You’re gonna only have one to start with? Yeah, it definitely depends on your use case. If you’re living on the desert. Absolutely. I’d say handlebar light first, just get a really wide beam pattern. And start with that, if you’re, you know, your local trails or straight line, like, basically World Cup downhill courses where you’re hitting for 40 miles an hour, then. Yeah, maybe helmet light first is a good place to start. But

Jeff 14:06
yeah. Yeah, I mean, because a lot of people when they start out night riding, obviously, you know, it’s something that you don’t know until you’ve tried it, like if you’re going to do it a bunch. And so yeah, I mean, rightfully, people are like, not going to make a huge investment. Most people that I know start with just a single light. And it is interesting that I feel like a lot of the lights previously on the market. They weren’t designed like specifically for helmet or specifically for a bar. So a lot of people would buy a light that they say, Well, I could put it on my helmet or my bar, just depending on what I figured out, you know, in these first night rides, but yeah, it sounds like it’s pretty crucial to have kind of a different setup for that beam pattern depending where you’re going to mount it.

Tom 14:54
Exactly. And that’s that’s really why we saw this opportunity in the market to begin with is we’re not Making a generic bike laid that can be mounted anywhere, you could you can take our bar light and mount it on your helmet, it’s not going to be great. Beams gonna be really wide, it’s going to be a lot heavier because we’re using more power for covering a larger area. So we have to have a larger battery and so forth and so on. It’s not optimized for helmet. But yeah, helmet light is and, and we basically designed the bar and helmet light beam patterns to work together. So that you’re not seeing two distinctly different things, but you’re just kind of seeing everything lit up evenly. I’d say for, for people just looking to try it out. You’re absolutely right. You know, people don’t want to spend a lot of money, if they don’t know they’re gonna like it and not gonna get into it. But I would do that. I would say remember, when you first started mountain biking as most people didn’t start with a $6,000 pivot or something like that, right? Started with a cheap bike. And then when they graduate and get nicer equipment, as they ride more like, oh, turns out, it is worth paying more for performance in my suspension in my wheels, dropper, post, whatever. That’s kind of the same way of lights, if you just get a very narrow beam, dim, handlebar light, and you stick it on your bars and you go night writing, you’re probably not gonna be able to see very well. And it might be kind of a crappy experience the first time, so maybe you wouldn’t want to do it again. But if you doesn’t mean that you need to go buy the most expensive light off the start. Just keep that in mind when you try it out. So that you don’t just say, Oh, well, obviously I don’t like night writing. Because I can’t see anything. It’s like, well, you can. But you may not start that way. And that’s fine.

Jeff 16:39
Yeah, yeah. I’m always trying to get people to join me night writing anyway. And so I’ll keep around, you know, some extra sets of lights and let people try it out. Because yeah, for sure is it’s different. It’s not for everybody, but I think it’s a lot of fun.

Tom 16:55
It is and doing it with groups is a lot of fun. It’s, it’s always a mess. When you’ve got you know, 10 different lights all shaking and pointing around shadows and flashes from all over. That’s totally different from night riding by yourself or with the gap between riders because your your elimination changes quite a bit. But group rides are always the best way to do night rides, I think.

Jeff 17:20
Yeah, for sure. So I want to talk about lumen numbers. You know, this is a number that a lot of buyers have been sort of trained to look for, you know, it’s almost like, I don’t know, back in the day, when you buy a computer, you’re like, how fast is the processor? And like, how much RAM does this thing have? And, you know, people look at lumens, that’s one of those numbers that’s like kind of front and center and a lot of marketing. So is that a good number to focus on?

Tom 17:50
Yes, and no, it is. It is a number that has value and tells you something, but it only tells you one thing. And that’s the total amount of light that comes out of the product. It doesn’t tell you anything about where the lights going, how much power it uses, what the runtime is the weight, none of that. And it’s kind of like your partner’s rally guy. So use the car analogy, it’s kind of like buying a car solely based on how much horsepower it has. You know, semi truck has like to 2000 horsepower, good, good being good, or like 600 horsepower, or 2000 pound feet of torque. But it’s going to be slower than my Honda Civic with 150 horsepower. Right. Also, if you don’t have good tires, and good suspension, then you’re not going to put all that power to the ground, you’re just going to do burnouts and make a lot of smoke and it’s going to look cool. But it’s not actually going to go very fast. So there’s a lot more that goes into having a fast car than just horsepower in the same way here. You can have a really bright in air quotes light. And it doesn’t, it’s not actually better for your visibility for seeing betrayal. So a lot of that comes into beam pattern, which can’t be conveyed by a single number like that. But it’s also your right, it’s what people have been trained to use, because it’s the only metric we’ve had on the industry. For many years. You’ll see in Europe, they started using intensity rather than total output. So they use Lux instead of lumens. So Lux is referring to the basically the number of lumens that are hitting a certain spot in the beam pattern. peak intensity is the brightest spot anywhere in your beam. And they’ll rate that with looks. Okay, that gives you a better idea of like the throw of the light and and how focused it is. But it still doesn’t tell you about the beam shape at all. So it’s kind of tough to say, Oh, you just got to go look at the shape for the trail on see what’s best, because it’s hard to convey that also you can get beam shots. But if you pointed out a wall in front of you, or if the shot is on a wall, it’s a two dimensional object that That’s not where your trail looks like. So it doesn’t really tell you what it’s going to look like on the trail. Honestly, the best ways to, if you can go get into a shop or you know, friends who have the lights, and actually test them out in the woods and see what the difference is. That’s the best way to kind of really see the proof in the pudding. As far as lemons go, though, your eye doesn’t respond linearly to lemons, either. So somebody says, Oh, I’ve got a light that’s twice as bright as this one. Yeah, it’s got twice the lemons, but your eye doesn’t see that it really takes almost four times as much light for your eyes to, for it to feel twice as bright. Yeah, there’s a lot of factors in that. But it’s, it’s because it’s not a, you know, an electronic sensor. Your Your eyes are chemical receptors, and you have a a pupil that is, you know, opening and closing, you have an aperture of controlling the amount of light coming to your eye. So if you stand outside in the midday sun, your people will constrict and let less light in to protect your eyes. When you go into a dark room, after being out in the sun, you can’t see anything, right as your eyes very slowly adapting to the darkness. And it takes a while for your pupils to dilate and let more light in. So when you go from a, you know, a, let’s say 1000 lumen light to a 2000 lumen light, what happens is yeah, you know, you’ve got twice as much light, but your pupil also constricts a little bit to react to that, because now you’ve got a brighter, more intense spot, and your light your eyes protecting you letting less light in, so it doesn’t feel quite as bright. And that’s where, you know, it’s not that important, really, to have 8000 lumens on your button. What that means is that you have to have a much bigger heatsink on the light, which makes it a bulkier product means you have to have a much bigger battery to be able to maintain that output for any reasonable amount of time, very quickly go from something that’s really optimized for putting on a bike or putting on your helmet to something not optimized for that, but super bright. And some people like that I kind of equated to doing a burnout like yeah, that looks cool. drive past you now.

Jeff 22:11
Yeah, burnout for your eyes. Yeah. Well, so I mean, can you? It seems like what some of these, you know, super high lumen lights are doing perhaps is? I mean, can you make up for the beam pattern with a really bright light? Like, could you just have kind of junky optics, but it’s fine, as long as you have like a ton of light, and it’s just pumping out everywhere.

Tom 22:37
Not really. In fact, you can make it worse by doing that. If you you know, that example, if you have a really like wide beam, like just really diffuse light where it’s not focused into a spot, then yes, having more power makes up for that. But it also means that your foreground, what’s closer to you is going to be really bright. And cranking up the brightness just makes that brighter, but it doesn’t project down the trail at all. So what you’ll find is that you’ll focus on the light on everything lit up really well in front of you, but you won’t be able to see the run out on trails and so in, it compensates a little bit for for intensity on certain spots, but it does not give you the real better visibility on the entire field of view, it doesn’t help you read the trail better. interested, if you have a same token, if you have a really narrow beam, cranking up the brightness doesn’t do anything except make that spot more visible and everything else looks darker. So it makes it harder to see anything else around you. If you just pile more lumens into one, one spot.

Jeff 23:44
Yeah, yeah, that makes sense. Well, so if we can’t really rely on lumens, I mean, like you said, it’s, it’s sort of helpful, but it doesn’t tell the whole picture. It sounds like Lux is maybe possibly another thing to look at. But is is there something else that you could look at to compare lights? Or is it really just, you got to try them and see how they work for you.

Tom 24:06
Trying is always best, but I know that’s difficult, you know, really websites is it’s hard to convey all this information because it’s not just singular data points, and there’s not not a really standard method for doing that, you know, like commercial lighting, they can they have you know, they’ll take slices of a beam pattern, you know, for like a candlelight in your kitchen. They’ll they’ll measure it in a horizontal slice and then they’ll do another slice at 90 degrees and they’ll basically publish a little chart showing you what the intensity plot would look like. No bike lights do that. So no manufacturers rather even we don’t do that right now and it’s mainly because there’s nothing to compare it to you know you can look and and not really know what that means. But we do have some we we try to take action RIT trail images were with a slider. So you can see the difference in the general spread and hotspots and color separation. And there’s a lot of not a lot, but there’s a few third party sites as well that you know, will do beam comparisons and you know, late shootouts and stuff like that, they’re not always perfect. But if you can get, you know, something that’s actually showing a beam shot, you know, on the trail, then you can get a better idea of like, Oh, that is a pretty narrow beam, I can’t see anything around my front wheel there. Yeah. And, you know, maybe that’s not something you realize as important. But if you’re on a pretty technical trail, and you’re trying to place your front wheel in the right spot, and you have to look down with your helmet, like to see where you know where the wheels going, then that’s not good. So that affects your night vision. And your balance is not how you ride during the day, you can normally see that of your periphery, you know, and the entire trails lit up in daytime. So having that peripheral spill matters. And you can see that in in beam patterns where you know, a light has a reflector, and so it’s got a really harsh, circular cut off in the beam, and everything outside of that circle is dark, that lets you know that you’re not going to see any of that in the real world. But, you know, we’re trying to get into local more local shops to bid so that you can, you know, pick stuff up and play with them. That’s a good place to start, you know, with any brand that’s out there, just go into your shop and asked to turn stuff on, you know, pointing it at a wall isn’t the best test. But if you can get into a you know, a dark supply closet even and just turn it on and see what the scatter looks like what you know, more than just the main spot that’ll that’ll help.

Jeff 26:50
Yeah, yeah, those the shots that you’re mentioning on the outbound website, where you can see sort of the beam compared to another one same spot in the trail. Yeah, I mean, it’s really helpful. And it is pretty dramatic, that difference that just that beam pattern beam shaped can make in terms of lighting up the trail.

Tom 27:11
Yeah, and there’s a lot of, there’s a lot of work that goes into that. And to date, a lot of in really, for most lighting manufacturers, the optics are pulled off the shelf, it’s, it’s fairly uncommon for them to make their own optics, because there’s already much larger industries. To your point, at the beginning of this, this is a pretty niche industry. Lights for bike riding, particularly for trail riding. So pulling stuff off the shelf is never going to be optimized for the trail because the market isn’t there. So we’re trying to basically create that with our with our own in house optical designs. And that’s not cheap or easy. But it’s, I think it makes a big enough difference that it’s, it’s worth doing.

Jeff 28:01
Yeah, so most bike lights that that we’re familiar with, tend to have like, three ish brightness modes that you can kind of cycle through. What’s the purpose of that? Is it just for speed? Like, if you’re going really fast, you want the brightest? And then if you’re going really slow, you can do the lowest or or is there something else going on? Is there another way we should be using those brightness modes?

Tom 28:27
You know, I, I’ve had a similar discussion with a couple of customers who were adamant that we need to change our user interface to be something specific either mode memory, or only two modes, or they need five modes for some reason. And it kind of speaks back to personal preference. I mean, a lot of it is going to be how you use the light. And I’ll tell you kind of how we’ve approached that and why. For the most part, it’s it’s so that you can control your output for the type of writing you’re going to be doing. If you’re going to be doing a longer ride or you’re not going to be moving as fast, then yeah, you want to you want to get more time, then you can put it on lower output and survive the ride. But for us, we wanted to cover the two main use cases for trail riding, being kind of the set it and forget it cross country crowd and more enduro style rides. So for the cross country crowd, that’s maybe not the best catch all term, but basically a ride where you’re going to be averaging a decent clip and pedaling and moving kind of up and down. You know, there’s not like a long, slow climb in the middle of it, you’re just you’re the whole time. You just don’t want to mess with the layout, but constantly, then you just we have an adaptive mode that basically starts at max output and slowly tapers as your eyes adjust to the darkness so that you don’t feel the change in light being get longer runtime. And that’s kind of we haven’t always turned on in that mode to start, because that’s what that crowd would do. they’d turn it on, and then never touch it. Again, they’re not thinking about runtime, they’re not thinking about modes, just want to go and ride. Yeah. And then we have a dedicated low and high. Because that’s what the Enduro crowd needs where you’ve got to climb where you’re going three miles an hour for the next 45 minutes. But then you’ve got a 10 minute descent, where you need max output, because you’re going to be going, you know, 30 miles an hour, or whatever, you want to see all the rocks in that regard. And so you can put it on low for the climb, use very little power, because you only need to see, you know, 20 feet in front of you. And then for the descent, you crank it up to high, and then high maintains 100% output so that it always is Max No matter what your battery is doing. So, yeah, I think for for most lights in general, it’s the way to think about it, I’d say for for your particular use case, as a writer is just what kind of rides you’re going to be doing. If you’re going to be doing rides that have long, slow climbs, and turn your light down for them, because you’ll get more time out of it. And the other benefit is that your eyes now adjusting to less light in front of you. Yeah, they turn the light back up, your eyes have adjusted the less light. So the brightness will feel even brighter the next time you crank up the the mode so that that’s sometimes helps with visibility at the start of a rowdy downhill.

Jeff 31:20
Yeah, that makes a lot of sense, too. I mean, that’s kind of that’s how we look at suspension a lot of times too, right? Like, you’ve got to climb mode, you’ve got to descend mode. And then, you know, I guess the the adaptive mode is more like a pedal mode where you’re like you said, you’re moving at kind of a constant speed, and you want to just keep going and not have to worry about it. And that’s a really good trick to like adapting the amount of light because like you said, your your eyes kind of adjust to it. And if you can do that without the rider noticing. Yeah, seems like you can get a ton of extra battery life out of that.

Tom 31:57
Yeah, that’s actually a great way to think about it. The Climb trail descend the old flux seat.

Jeff 32:01
Yeah, I was gonna say that. But yeah, I thought that might date me year, or something. But yeah. Yeah. Yeah. So let’s talk a little bit about the batteries. How do you determine the optimal battery size for a bike? Like, is there like, a ride time that you’re shooting for? I mean, it seems like most lights tend to offer kind of the same amount of battery life, but like what’s as an engineer as a product designer? Like? What’s kind of your take on that?

Tom 32:36
Yeah, so a lot of a lot of factors go into it. First and foremost, it’s the packaging. So we’re, we’re making all self contained lights, because we don’t like having external battery packs, at least not being forced into using

Jeff 32:48
the wires. And yeah, where do you put stuff? And yep,

Tom 32:52
how do you manage your frame without scratching it or whatever. So with that means we can’t just pack giant batteries in there, because then you have a big bulky light that nobody wants. So a lot of that is comes down to the cell size and shape, and then the efficiency of those cells. So right now, there’s basically only two cell sizes on the market that make any sense to us. It’s an 18 650 and a 21 700, that are both lithium ion cylindrical cells. And pretty much what everybody uses with a few exceptions. And that means if you got a cylinder that’s 21 millimeters in diameter, and 70 millimeters long, you can only fit but so many of those in certain arrangements. You can’t just pack them flat, like lithium polymer cell. So fitting that in the housing is step one. And second, most important thing is how much light do you actually need to for that specific product for where it’s going to be mounted? And then what kind of runtime Do you want? So we’re, we try to shoot for at least two hours in our adaptive mode, because that covers most people, not everybody, because it’s impossible to make a product that does everything that everybody wants, but most people are night riding local trails, because they’re not traveling to, you know, some exotic location to ride at night. They’re going there. Today.

Jeff 34:22
Yeah. And I always tell myself, I am like, I have these trips. You know, I’m like, going somewhere and I’m like, I’m gonna bring my lights because I’m going to do a night ride while I’m there. And then I never do I get I get too tired writing during the day.

Tom 34:34
Exactly. Yeah, we run into that in the cinema Mountain Bike Festival, too, because we do a demo ride there on the Friday night of the festival every year, and we get a lot of people that come up to us at like 4pm and say, Yeah, I think I’m gonna skip it because I’m writing all day and I just started drinking beer. So tomorrow that’s fine. veterinary, the so the, we basically are back calculating how much battery capacity we need for how much light output we need for a given amount of time, right? So the handlebar light because we want a wider beam, which means we’re covering a larger area of the field of view. So we need more, more light to do that, which means we need a larger battery to get the appropriate runtime. So we’re, we’re basically do the same thing with the optics, where we’re figuring out the intensity distribution we want on the trail, and then back calculating how many lumens it takes to produce that beam at that intensity. Okay, so that all battle directly weighs into what type of batteries we use, and how big they are, essentially.

Jeff 35:44
Interesting. So, one of the things that LEDs, you know, there was this shift, spent a while now and again, I will date myself, but, you know, a while back, there was another technology that was used for the bulbs and for lights, I think it was called H ID. And one of the problems with that, or, you know, the big inefficiency with with that was these bulbs were like really hot like they produced a ton of waste heat. And but LEDs seem to have the same problem, right? Like I’m reading a lot of stuff about Yeah, like, and you’ve mentioned it heat management and all of that with LEDs. Why didn’t why do they produce so much waste heat? And like is, is there something better on the horizon than LEDs?

Tom 36:39
Great question. So no, there’s not something better than LEDs, but LEDs are still getting better. The inefficiency comes down to just the raw efficiency of converting electrical energy to photons. And it’s of a certain wavelength. So it’s not just blue. It’s a broad spectrum white, and it gives you color rendering that you can actually see differences in different colors. So essentially, what you’re doing is you’re pumping electrons into this LED chip that’s producing blue light, that is now hitting a yellow phosphor, which is then converting that blue photons into a broad spectrum of different wavelength, longer wavelengths. So you can get the mix between the blue and the broad yellow to make a white light. So every step of that has an efficiency loss, the LED itself, converting blue photons, and then the phosphor and all that, if it’s inefficient, it’s producing heat. So you know, the example you mentioned with H ID or you know, maybe a simpler one is with incandescent bulbs in your house. Yeah, and this bulbs are cheap, they’re just a filament that you’re running enough power through to heat up to the point that it’s glowing red hot. Yes, are incredibly inefficient. So yeah, terms of limits per watt, you might be at best 15 lumens per watt. Most are like 10. Yeah, LEDs, we’ve, we’ve gotten, you know, the record breaking led that we had actually helped with that Cree was 303 lumens per watt at the time. So 30 times more efficient than the that light bulb that doesn’t. But under 100 lumens per watt has been a pretty good like benchmark for an efficient light source these days. However, the like theoretical, like maximum conversion efficiency, you can have four photons produced at 555 nanometers is is going to be 500 Something plus obits per watt. Because that means if you’re at 100 lumens per watt, that 80% of that energy is still waste. Technically speaking, it’s not it doesn’t quite relate that way because of how your eye responds to red, green and blue peaks and all that. But point is, there’s still a lot of inefficiency. And it’s just less than older technology. So that means you have to manage the heat coming out of it. And if you don’t do that effectively, or if you’re trying to pump out, say 8000 lumens and a very small heatsink area, you either need a massive heatsink, or you need a lot of airflow to do that. And so what happens a lot is you’ll see like thermal controls where the light, this light gets 2500 lumens and then seven minutes into runtime under it because it’s too hot. And what we realize is that it’s not the LEDs, we can actually push really hot. It’s not the LEDs that are going to die or anything like that. It’s touch temperature. If you touch your light, and it burns your hand, that’s a problem. So we’re actually controlling the case temperature with our thermal controls and letting the LEDs run a little bit hotter and so What we can do there is basically push out our thermal control so that you don’t have that immediate drop off where the light is now screaming hot, and you have to pull back the power in order to get it to cool down. We’re basically trying to give you just enough thermal capacity so that if you’re moving at all, like two miles an hour, though, it’ll stay cool and be fine. Yeah, it’ll get warm. But it’s not gonna get hot enough to burn. Yeah.

Jeff 40:25
Yeah, yeah, I mean, the light bulb example is actually what got me thinking about this where, you know, if you have like, a incandescent bulb in your house, like, and you need to, you know, take it out of the socket, while it’s on like, you can’t touch that it’ll burn your hand. But with the LED bulb, like, those are not even hot to the touch. And so why is it that bike lights are that much hotter? Are they that much brighter? Are they in like a smaller space? Like, what is it that that they are really like heat sensitive compared to like what we’re used to in our houses? Yeah,

Tom 41:00
I would say that some LED bulbs in the house do get screaming lava hot. But that also comes down to they’re designed for the to have enough thermal mass and heatsink to not have airflow, right because a bowl broadside a lamp doesn’t have airflow to cool it down. bikes do. However, if you stop and your your light is still on high, and you’re farting around with your derailleur adjustment or something below the trail. Yeah, your lights gonna heat up because there’s no airflow. And we’re trying to balance, you know, we could make more thermal mass to so that it’s perfectly stable in all conditions and an equalizes, but then you have a heavy, bulky, an optimized product. So it’s really comes down to, like lights are trying to push more power out of something small. They don’t want to make something big and ugly.

Jeff 41:54
Yeah, yeah. Makes sense. Lots of trade offs, lots of considerations that dictate that design for sure. And obviously, a lot of thought goes into that. While we’re talking about heat. So I’m curious to know, you know, in the past, there’s been reports, maybe rumors of like bike lights, causing problems, you know, catching on fire and things like that. What would cause a poorly designed or manufactured light to pose a safety risk? Is it? Is it the light? Like, is it the bulb overheating? Is it the battery? Like, what is it that that people need to watch out for? That can maybe give them a clue that like something, something’s unsafe about a light?

Tom 42:38
So people shouldn’t have to watch out for any of that? Right? Does not have the ability to burn your house down? Right? Yeah, that’s actually that’s actually something we think about in our optic design to the benefit of our our designs, where we’re spreading out having a much larger optic area is that we’re basically running less light through it. It’s less light density. So rather than pumping 2000 lumens through a one circle, we’ve now spread it out to a much larger area. So if you turn your light on high, and stick it in a bag of like black cloths or GIF, it will not start the back on fire. We actually tested this by taking 100 Evos in in a box and turning on 20 of them in the box. And just seeing what would happen. box gets very warm. Yeah, but it doesn’t

Jeff 43:32
start things on fire. Didn’t lose 100 Evos that’s good too. You must have been pretty confident.

Tom 43:38
Yeah, well, there’s a longer story behind that but I would say that the two two ways that things can go wrong at home are the the lens you know, melting something by being pressed against something in high output mode, and then the batteries catching fire. Neither of those are legitimate like that. Not that they’re not legitimate. Neither of those are real concerns with products today. You know, you got something from Knight Rider or Leighton motion. They have like lockout modes to prevent you from accidentally activated them in a bag. If you take a you know, very high power bike light and you turn it on max power and you stick it down on the black vinyl on your car seat. You might melt it, don’t do that. Yes me how I know. And then for the batteries every legitimate manufacturer that’s out there is using quality cells, you know from Samsung or LG or or you know, they’re not using garbage stuff from from China. The stuff you get on like Amazon for 40 bucks. That’s that’s where all these horror stories come from. It’s from batteries that are charged with chargers that don’t have any regular Asian, they’re just putting out voltage. And so they’re not. They don’t have any intelligence in them to say, Okay, I’m I’m overcharging or I’m pushing too much current or there’s something

Jeff 45:10
Yeah, they’re not talking to the battery, like getting feedback from the battery itself.

Tom 45:14
Yeah, it’s just pushing power towards it. And with cheaply made stuff, you get people cutting corners. And what happens you get solder joints that fail, you get insulation that gets worn through and bridges and shorts in various places. And you get cells that are just bad because they’re not using quality cells. And so the, the the reports of like a bike like catching fire and burning someone’s garage down, there are credible sources, that’s real, but they’re all cheap garbage lights, you know. And pretty much most lights today are USB rechargeable. And it’s basically impossible to miss charger USB device, because they have a chip and they’re regulating the power coming in. Interesting. You can plug in 100 Watt charger, to a light that can only take five watts of input power, and the lights gonna take five watts, not 100 That’s because there’s no proper circuitry in there. I have actually witnessed a battery pack catch fire on a ride before. Out in Pisco, we were doing his night ride and the guy put his cheap Amazon late battery pack into his backpack. And we’re riding and started seeing smoke coming out of his pack. And it was it was the craziest thing I’ve ever seen. Wow, as quickly took that off and dumped the light unplugged it and tossed it and it cooled down. It was okay. But it was yeah, it was melting through the through the pack was great.

Jeff 46:49
Whoa, whoa. So yeah, I’m hearing stick with the name brands. And also, I hadn’t heard that. USB chargers are potentially much safer. It sounds like and most bike lights, I think even the cheap ones. Now. Most of those are USB. But yeah, that’s good to know.

Tom 47:10
I say that now I’m going to find some cheap, USB rechargeable light that isn’t safe. But yeah, everything else has a has a specific chip in the light that’s telling the charger, what it can take. And it will not allow more power than that unless something has gone wrong. And it’d be pretty hard for something to go so wrong that the charger itself thinks it’s okay still to send more power. But doesn’t think something is wrong, if that makes sense. So

Jeff 47:39
yeah. Yep. Makes sense. Cool. So do you have any tips for us about night riding or maybe getting the most out of a bike light on the trail,

Tom 47:51
something I see pretty regularly is people trying to figure out how to angle their lights appropriately. And you know, people with like dual smaller lights on their bars, they’ll spread them out and kind of point them in or whatever. And we’re point their home late way too far down and had a guy that said his bar light was just too dim, he’s just gonna take it off, and it’s like pointing up in the air. How about you point that down, but forward, the trail made a huge difference. I would say that the helmet angling is where it’s really more difficult, the bikes pretty easy to figure out. And a lot of people will angle their lights either too far down or too far up. And what that forces you to do is ride with your head in a really weird position, which affects your riding during the day you’re not thinking about, you’re not trying to position your light pattern where it needs to be because you’re not riding a light. So your head is just in whatever position it is your natural riding. And at night, if your light has pointed too far down, now you have to stick your chin up to get your light on the trail. And so you’re writing and you can’t see as well down low and you’re just kind of in an awkward position. Same way if it’s too far up, where you have to look down and kind of look ahead like that. It’s just awkward. So yeah, I position your helmet light so that it’s pointing down the trail, not right at your front wheel. Because it ruins the depth you get from your handlebar light and you know, pretty much everybody you talk to if you want to go fast look ahead, look at the helmet lights job is to look ahead and then look through corners, you know tight switchbacks and things like that. So positioning the light so it’s down the trail and not right down in front of you. When you’re in a natural you know whatever your natural riding position is that’s that’s a good place to start.

Jeff 49:42
That will help Yeah, is there so thinking about the handlebar one because like you said that one. It is pretty static like much more so than your helmet lamp. Is there like an ideal angle like could we could we see like bubble level like on our lights so we know we got it in right area like, what are we talking like five degrees down 10 degrees up like what’s what’s ideal?

Tom 50:07
You know, back to earlier discussion, it depends.

Jeff 50:13
What is Tom? Like what works for you?

Tom 50:16
Across the board, take your bike, your light on your bike and just make it level. Yeah. small adjustments from there if you decide you need to there’s, you know, some people prefer to have their handlebar light and board down, you know, light up the foreground and have it light up. That’s fine. I wouldn’t point it straight down, I also wouldn’t put it too far up, up basically just wastes all the light, you’re not you’re not getting any real benefit from that down, there is some benefit, depending on your type of writing and your personal preference. But I’d start with it level.

Jeff 50:51
Sort of like saddles. I mean, it sounds like you know, like you, some people like it a little up some people like a little down. So if you start in the middle, you should be pretty safe.

Tom 51:00
Yep. Yeah, that’s good way to think of it. Cool.

Jeff 51:04
And then yeah, any other tips for getting the most out of Viking at night, or any, any inspiration you have, for people who are thinking about getting into night writing.

Tom 51:19
I’d say just first of all, just go do it. Find some buddies with some lights, like yourself and borrow their lights and get out and try it. And just recall that, you know, your first experience mountain biking maybe wasn’t great. And you learned a lot from it, and it’s better. Same way with my reading, there’s, there’s always things you could be doing to improve your setup and improve your mindset. You know, if you’re going out, chasing kom is on Strava, then maybe don’t do that in general. But start reading by doing. And don’t get upset if you’re going slow, because you can’t see as well figure out why you can’t see as well and address that. The you know, sometimes I would say that for the average person, night riding is a necessity. You know, they live in an area where it gets dark after work. And so for half the year to ride, kind of have to ride in the dark, or just on weekends or whatever. But a lot of people get very different experience out of it. And it’s not having the best lighting setup isn’t necessarily the thing that makes it the best. So I like just writing a night, I test a lot of stuff. But I also like being able to see really well because I like riding my same gnarly trails the same way I do during the day. But some people just enjoy the fact that they’re riding a trail where they can’t see as well. So they’ll use a smaller light, or specifically use a narrow beam light where they can only see the thing are looking at. Because it’s more exciting, because it’s different.

Jeff 52:57
Feels a lot faster. And a lot of ways. Yeah,

Tom 53:00
yeah, that’s not necessarily a bad thing. It’s, it’s just different. So you can you can get away with not having a supremely dialed setup, if you’ve got the right mindset for it. And to that end, you know, night writing is a good good way for people to see things differently. You know, your trails look different. During the day, if the sun is straight up ahead, or if it’s at, you know, just at dusk on the horizon, the trail gets lit up very differently. And then as you’re going through a winding twisting trail, depending on what where the sun is around you that trail is, is being lit up differently. At night, the lighting is extremely consistent, it’s always in the same spot on you where you’re going. But it is never the way it is during the day. So it looks the way you read that drop feature or the section of trail, you may see a line that you never saw before because of just the way it’s lit. And I think that’s a good good thing to keep in mind when you’re night writing is not just trying to you know, getting something different out of the experience, right freshening up local trails, and then maybe go back during the day and realize, Oh, I could do this in this section. And I never really thought of it before but like jumped out at me at night. That’s that happens a lot with people we ride where we take, let’s call them alternate lines. And sometimes they work sometimes they don’t. But it it keeps things fresh.

Jeff 54:29
Yeah, yeah. Well, that’s great advice and inspiration and yeah, ton of knowledge about bike lights. That’s super helpful for those of us who ride at night, so yeah, thank you. Of course. Well, we’ll have a link to the outbound lighting website in the show notes where you can check out some of those photos we’re talking about showing beam patterns and you can also find a little bit more information about bike lights and how they work. So we’ve got this week we’ll talk to you again next week

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