Reelight bike lights

The Danish Reelight has gotten quite a bit of attention over the past year ever since they introduced their unique, battery-less bike lights. The iFlasher light was nominated for an award in the Danish INDEX Design Competition.

Hiawatha Cyclery in Minneapolis has had the Reelight bike lights available in the U.S. for a while now, but the SL100 and SL120 lights from Reelight are now becoming more widely available in the USA. Dealers this year were signing up left and right for the lights this year at Interbike, and I know that my local bike shops began receiving their shipments of these lights this week.

I evaluated the SL100, which is the basic model with front white light, rear red light, brackets and two magnets for each light. The lamps are mounted on the wheel axles; the magnets are mounted to the spokes. As the wheel spins, the magnets pass near the lights generating a small electric current which momentarily illuminates the two LEDs in each light. The result is an LED “blinky” bike light with no batteries. Here are the lights as seen on my commuter bike.

Reelight bike light on front wheel Reelight red tail light on rear wheel

Installation is fairly straightforward, though some dexterity is required to mount the spoke magnets. Wheels with disc brakes may require a version of the light with longer brackets. One bike mechanic I spoke with expressed some concern about installing these lights on a wheel equipped with quick release skewers — he thought there was a chance the magnets can catch the quick release and open it on the fly. The Reelight sales rep I spoke with, however, told me that QR mounting is common and he’s not aware of any problems or mishaps arising from installing the Reelight lights on QR wheels. The only problem has been with mounting the lights on some front suspension forks with recessed hub bolts, according to Reelight.

The lights are reasonably bright and flash twice on each wheel revolution. One common concern is the low mounting location of these lights. According to Reelight, though, “Lights mounted at the hub are not a new thing.” Particularly when riding next to heavy traffic on a dark morning I can see an advantage of a low-mounted light: they are always in a dark place and appear more visible. Handle bar mounted lights have a tendency to get lost in the “noise” of car headlights and street lighting, while lights that are low to the ground don’t compete with those other light sources.

If you ride with rear panniers, your rear light may be partially covered as they are on my bike as pictured here. If you don’t ride with panniers or if they don’t extend all the way to the hub, you should be fine. For those with panniers, Reelight plans other mounting options in the future that may help you out.

Reelight bike light -- obscured by pannier
I really like the Reelight bike lights and I don’t hesitate at all in recommending them. The SL100 is the basic light as pictured here. The SL120 is almost identical except it has a standlight feature — a little bit of charge is saved during operation so that the lights continue flashing even when you’re stopped. I need to emphasize that these are strictly “be seen” lights — if you ride away from street lighting, you’ll need a more powerful headlight to illuminate your path. For city riding, though, these flashing LEDs are a low maintenance way to make you a little more visible.

While U.S. dealers are now receiving the lights from their distributor, I’ve heard there might be problems with product displays. If you want this light, you might need to ask for them at the shop. The basic SL100 with two lights is about $50 at U.S. bike shops; the SL120 two light kit with the standlight is about $60. The lights are distributed in the USA by J&B Imports.

Note: CBB previously reported that the SL100 retails for $40 and the SL120 retails for $50. We regret the error.

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0 thoughts on “Reelight bike lights”

  1. Joel says:

    I have a set on my commuter and like them. Only problem is the chainstay on my bike is such that I can’t raise the rear above level to the ground. I would prefer a little angle up on it. I will probably get a set for the touring bike I’m building also.

  2. Franky says:

    I ordered the basic version from the UK last year for my road and hybrid bike (both with quick release) and haven’t had any problems installing them and they worked without problems ever since. The lights are not meant to illuminate but to make you more visible without having to worry about dead batteries. I highly recommend them.

  3. Jen (SLC) says:

    I have a set on my commuter. I got my set on Amazon for $35 or so. They’re great. I initially installed them with qr skewers, but I was a little worried about them being stolen and swapped the qr for locking skewers. It’s worked fine with both.

  4. jason (sd) says:

    I have had one set of SL100 on my commuter for a few months. Works great, can’t forget to turn off, can’t forget to turn on. On a completely dark road there is enough illumination to see large objects, but not necessarily with enough time to avoid the object. As I hate recharging batteries, this is currently the only light I use. I would probably not want to go down an unfamiliar road with out something else. The point I am trying to make is these are quite bright for a blinke with no batteries.
    Installed a set of SL100 and a set of SL120 on my trailer last night. The SL120’s are interesting; I could not get them to flash after the install. So I went for a 7 block test ride. It took less than 1 block for them to start blinking. Then after I stopped they kept flashing, the front on for a few minutes, and the back one less then 30 sec. Maybe this has to do with the distance from the light to the magnet.
    I would agree that the mounting is not ideal for every bike. However with a little imagination, I think these will work for the vast majority. As far as the QR thing; isn’t the magnet going to pull the lever toward the wheel. Anyway, haven’t had a problem

  5. SuperCommuter says:

    I have a set – love them! My LBS installed them for me so I didn’t do ti myslef, but I did read through through teh instructions and they seemed pretty straight forward.

    +1 Jason (sd) always on when you need them.

  6. Jim G says:

    I would love to see Reelight re-work the standlight functionality of the SL120 to create a non-blinking/steady-on light. If the capacitor circuit can power the light *after* the wheel stops turning, then it should be feasible to also power the light *in between* magnet pulses.

  7. Dan says:

    I also have an SL-100 set on my commuter. They are always there, and I forget about them until I need them.

  8. John says:

    I originally ordered a set of 120s directly from Reelight in Denmark – it couldn’t have been easier over the web and the service was great. You can also order extra sets of magnets if you want to get up to power faster, but they generally aren’t needed.

    Installation instructions must be followed – the spoke magnets need to pass by the light housing at a distance of roughly 2mm (1/10 in.) to be most effective. I needed to bend the bracket a bit to do this on my QR wheel, but they have worked very well.

    The capacitors store enough power to keep the lights flashing for several minutes while stopped after a ride of only a few blocks. The flash rate is steady and not tied to wheel speed.

    Easy, efficient and effortless to use – just ride.

  9. David says:

    very cool, maybe better than the old dynohub type setup I was contemplating. Low or no extra friction sounds good. Add a few extra magnets on the other spokes (balanced of course) and the capability alluded to by Jim G (nice idea for next generation version!) and I think we have a winner. Whats to stop us locating the light above the axle with just a little “sensor” to generate the power down by the spoke/magnet, and a wire to connect to the light at a suitable location up where they will do the most good seeing and being seen?
    The next thing to do is mandate them be provided on all bikes as standard spec. That would bring the price down where it should be, and suddenly all bikes would have night riding capability. I wonder what reduction in bike accident rate would be had if this were the case.

  10. Fritz says:

    Reelight plans to introduce other mounting options in 2008, including seatstay and fork mounts. I think they’ll move the magnet with it, though, instead of Dave’s idea where the magnet stays in place.

    Thanks for all of the comments, everybody!

  11. jason (sd) says:

    David check out
    for locating the lights where you want them

    Also have a set of these; not quite as bright, more time consuming to mount; wires are restrictive to mounting options (a little short for some situations) and can break.

    I have them set up on the wife’s commuter to flash alternating with the reelights. Very efective.

  12. ben says:

    i owned these light for about 2 weeks. they worked great. then all of the sudden the front light stopped working. its a great concept but i wish i had spent my money elsewhere.

  13. […] out on you right at the darkest point in your ride home. Consider spending the extra money on some Reelights or Pedalites. Both are great options for adding visibility to your bike without ever worrying about […]

  14. If you want to get your hands on the marvellous Reelight then you can Buy the Reelight SL-120 at our site. They’re the capacitor model which means that they stay flashing for up to 2 minutes when you’re stationary. They’re really good, everyone in our office has some!

  15. Ted says:

    Looks like you’re riding the raleigh one-way which is the bike I would install these on as well. thx for the review

  16. Barry says:

    Thx for the review. Can you tell us which panniers you’re using? They look like a good, safe and simple design in the photo.

  17. Fritz says:

    Barry, the panniers are Avenir panniers. I threw them away because they fell apart after about one year of use, unfortunately.

  18. Michael says:

    There is a similar battery-free bike light on the market, it is called magtenlight, a 15 Lux front lamp plus rear light, powered by a friction-free, contact-free generator, the generator is not a hub dynamo, but a detachable type of generator, driven by a pair of magnetic gear , Check it out at

  19. Johnny says:


    I like the review of the Reelight this is the first time I have heard about this new light, generator lights are very nice for their sustainability I especially like the Reelight’s frictionless no moving parts design, they will last longer then traditional generator lights and they will not rob power from the rider. Does anybody know if they have a warranty.

  20. […] build steps are the new Velo Orange fenders, a shiny chrome chain guard and some ReeLights so there’s no fiddling with lights on our date […]

  21. Todd Scott says:

    I *used* to love and recommend these lights (actually the SL120 model), but both Reelights have stopped working after a handful of months. I just returned my to REI this evening.

  22. John Hogan says:

    I’m having trouble installing my Sl120.
    Front light went on fine.
    But I’m stumped when looking at the bracket (I assume it is the straight/flat bracket not the arched bracket) and how it gets around the gears.

    Set comes with two brackets. An arched bracket and a straight bracket. Direction photos don’t tell me which for front and which for rear.

    Can somebody help me?

    Thank you

  23. Steven Whitfield says:

    I have the 120 on my Surly Long Haul Trucker. Rode home tonight with them and they worked great. I will use them in addition to all my reflectors and powerful battery powered head and tail light. They are great for additional visibility. If someone hits me with these it is because they meant to, not because they didn’t see me.

  24. Paul in Minneapolis says:

    I installed Reelights sl-120 on two bikes.
    The extended were needed for my Dutch city bike.
    The front lights started to not work after one to two thousand miles before the totally quit.
    Reelights replaced the two front lights. When I changed them, I noticed the old lights clunked when shaked – the core came lose.

    Very sad, the lights could be killer….

    All my bikes have dynamo hubs (German) with B&M lights – after years and many thousands of miles they keep working like day one..

    Maybe Reelights will improve the design..
    I’m willing to pay $150 if they were built to last… I hate batteries that much.

  25. Christian says:

    The SL150 and the SL250 don’t blink. You can find out on the website. Look for a SPECS box on the right side.

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