Just in time for the end of daylight savings and shorter trail days, we’ve put together a mountain bike light buyers guide. Mountain biking at night adds a new dimension to familiar trails and it’s a great way to extend your riding season; use this guide to find the best lights for you!
Trail speed and terrain considerations
Before you choose a light for mountain biking it’s important to consider the types of trails you’ll be riding at night and the speeds you expect to carry. For example, if the trails you’ll be riding are technical you’ll want a brighter light with better fill than if you’ll be riding wide dirt paths. And if you want to go fast you’ll need a light with more range (i.e. power) than if you expect to slow things down in the dark. Also keep in mind how often you’ll be night riding; if it’s only once or twice a month in the winter you may not want to sink a ton of money into a light system.
Where will you mount your light?
There are basically two choices here: bar mount and helmet mount.
A helmet mounted light tracks wherever you’re looking – around a switchback, at a rough patch of trail, etc. – which many riders prefer. The trade-off is that helmet lights generally aren’t as powerful as bar mounted lights due to weight considerations. Remember, with a helmet-mounted light you’ll need to strap the battery pack to the helmet itself or in a jersey pocket which can harsh your flow on the trail. Lights are typically mounted to a vented helmet using velcro or stretchy straps. Helmet mounted lights typically shine down on the trail more which is good at eliminating shadows but shortens the distance the light will carry forward.
Bar mounted lights are typically more powerful and tend to feature larger battery packs that are longer-lasting. Light mounting arrangements may vary and some are better than others at dealing with tapered bars and varied bar diameters (look for ones with rubber straps or a clamp with plenty of screw length). Batteries are usually mounted separately and most riders choose to place them under the stem or in the frame triangle below the top tube. Light at bar height will shine farther down the trail but will tend to produce more shadows in uneven terrain.
Many small- to medium-sized light kits include hardware for both helmet and bar mounting so you can see which one works best for you. Of course the best of both worlds is to ride with a combination of helmet and bar lights but for beginning night riders a medium-power helmet lamp is a good start.
Light emitters: LED or nuthin’
These days it’s hard to find major bike light manufacturers offering anything other than LED lamps and it’s no surprise: LED lights are reliable and super efficient. Stay away from lower priced halogen and HiD based systems – these lights suck battery life and produce a ton of excess heat.
To compare brightness between light systems, check the number of lumens (companies often claim competitors’ lumen counts are flawed but it’s still a good starting point). At a minimum you’ll want about 150 lumens to ride trails at night – and at that point you’ll be find yourself riding pretty slowly. 
Beyond lumen counts, the actual beam pattern is important to consider. The simplest pattern is a round one (since LED bulbs are round) but much of that light is wasted on the edges of the trail. Some lights offer a round beam pattern with a center “hot spot” and a diffused outer halo that’s good at illuminating your peripheral vision while highlighting what’s ahead. A well thought out beam pattern on a bar mounted light system all but makes up for the fact that your light doesn’t follow your eyes like with a helmet-mounted system.
Most lights ship with multiple light modes (high, medium, low, strobe, etc.) and some even offer customizable light modes but in our experience there’s no need for more than one or two modes. High mode works best for most rides unless you need more run-time (more on that in the next section) while a strobe mode is mostly good for commuting and dusk rides where you’re more concerned about being seen than actually seeing the trail.
Batteries matter
The heart of any light system is the battery so it’s important to pay attention to quality and reliability. Most mid- to upper-level light systems include a rechargeable Li-ion battery while less expensive systems may ship with NiMh batteries. Charge times can vary widely (from as little as 2.5 hours to 10+ hours) so be sure to check – there’s nothing worse than forgetting to charge your light the day before a big ride. Be sure to follow the manufacturer’s charging instructions to maximize the life of your battery.
Longer battery life comes with a trade-off: batteries are heavier and more expensive. Look for run-times on high that are at least long enough for your typical ride (we look for 2 hours minimum). To compare systems it can be helpful to calculate a simple ratio of max lumens to run-time on high. For example, if a 300 lumen light gets 4 hours of run time (240 minutes), that’s 0.8 lumens per minute (this number doesn’t mean anything – it’s just for comparison). If another light’s ratio is 1 lumen per minute that means the second light is more efficent (holding other things like battery size/weight constant).
Because batteries will degrade over time and technology is changing rapidly we don’t recommend purchasing used bike lights unless you’re able to test and verify actual run-time yourself.
Tail lights
It’s always a good idea to bring along a blinking red tail light on any night ride, even if you don’t expect to encounter any cars. Choose a bright, inexpensive light that can be easily strapped onto a hydration pack or attached to your seatpost.
Recommendations (Updated November 2, 2011)
At this point we’ll offer some specific mountain bike light recommendations but remember to consider your budget and how you’ll be using the light to make the best choice. Products listed below are ordered by lumen count.
NiteRider MiNewt.600: This 600 lumen light is USB rechargeable and is a one-piece unit meaning there are no cords to get tangled on the trail. The smart charger juices the MiNewt in about 5.5 hours for 1.5 hours of run-time on high. Handlebar and helmet mounts are included and at $149 MSRP this simple little light is a great value.
Magicshine GMG Special 900: This simple light system pumps up the volume with 900 lumens of light and a battery that offers about 3 hours of run-time on high. At just $89 MSRP this is one of the best dollars-per-lumen values but because this system is fairly new to the market, the jury is still out on reliability. So far so good!
Light & Motion Seca 1400: The mack daddy of our recommendations, this light produces an astonishing 1400 lumens of light and weighs just 500 grams. You’ll get about 2.5 hours of battery life on high and you can mount this portable torch on your helmet or handlebars. The side-beam pattern is second to none but all this performance comes at a price ($699 MSRP). In our tests the Seca 800 works very well too and can be used comfortably as a bar-mounted light.
You can read in-depth reviews of even more bike light systems or read and compare mountain bike light reviews for these and dozens of other light systems on the market. See you on the trail!
Related posts:
Subscribe in a reader
We just updated the post with links to deals on select recommended bike light systems. In particular, HuckNRoll.com is giving away a free Vega 120 light with purchase of both the Stella 300 and Seca 1400 for a limited time.
Also check out Amazon.com to get the NiteRider MiNewt 250 for just $115.
Pingback: SingleCrown » Guide: Trail Lights
I never considered riding at night but will have to give it a try. Thanks for the info.