Quick Take: Serfas Thunderbolt Tail Light

Lights Lights Shootout

Why You Want: You’re looking for a bright tail light that’s durable, easy to maintain, and can be mounted almost anywhere.

Pros: A 30-LED strip in this light produces a 35 lumen taillight, plenty bright to be seen from a far. An internal lithium-ion USB rechargeable battery means the days of disposable batteries are gone. Light silicone casing means this light is both water resistant and be quite durable, be it on the bike or in your bag.

Cons: The power button is sometimes hard to depress, we would have liked to see a more responsive button.

RoadBikeReview Take: The most important feature of a taillight is to be seen and this taillight does that quite well. The 30-LED strip produces a bright light rated at 35 lumens, bright enough to be seen for up to a mile according to Serfas. The housing is made of light silicone, which makes it both water resistent and durable, standing up to the elements without a probelm. An internal lithium-ion battery makes maintenance a breeze – only needing a usb cable to recharge this light. We’re happy to see more and more lights offered this way, as the days of buying small AAA batteries is over.

Mounting is done with two straps that make it easy to mount the thunderbolt to a variety of tubes on your bike. This light works well on your seatpost, but we’ve seen them mounted to seat stays as well… the most creative mount was on some wheel spokes for a Tron like effect.

The Thunderbolt comes in 7 different color options, including black, which should make it easy to find one that doesn’t clash with your bike.

Price: $45
Run Time: 1.75 hours (high beam); 7 hours (low beam); 3 hours (high blink); 9.5 hours (low blink)
More Info: www.serfas.com

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About the author: Thien Dinh

Thien Dinh gained most his cycling knowledge the old fashioned way, by immersing himself in the sport. From 2007 to early 2013, Thien served as RoadBikeReview Site Manager, riding daily while putting various cycling products through its paces. A native of California, Thien also enjoys tinkering with photography and discovering new music.

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  • GirchyGirchy says:

    I’ll pass – high-ish price, some ELFs on Amazon reviews, low run time, and no mention of a warranty. I prefer AAA-powered lights anyway, it’s easy to carry an extra battery – not so much a spare light.

    If I were going this route I’d probably go for a Blackburn Super Flea. Much longer run time and great CS/warranty.

  • aclinury says:

    $45 for a piece of made-in-China electronic that should be < $10? Pass.

    • francois says:

      >>$45 for a piece of made-in-China electronic that should be < $10? Pass. Suggest a viable $10 option and you might gain some credibility.

  • Tony says:

    Have owned this light for several months. Definitely one of the better performing taillights that I’ve used. Not only is it bright enough, but also very easy to install and has a sturdy feel to it. Love the fact that you can recharge with a usb cable. Of course, the price is a bit high, but you can definitely find for less than msrp….just do your homework. I got mine for 25% off during a LBS promotion.

  • froze says:

    I actually ended up getting two of these (white version) for the putting on the front stays as flashers, their slightly angled outward about 5 to 10 degrees to increase side visibility. I use them in the high flash mode which gives about 3 hours of light which I expected the battery life to be short due to the size of the light, thankfully their rechargeable. But their really bright and I seem to be getting the attention that I wanted. The only con is the price, I paid $38 a piece but that seems high for how inexpensively made they seem to be, however I haven’t found anything near that level of brightness that will attach to the stays without being cumbersome. I checked out the Blackburn Flea and the anemic Click as well as the very anemic Knog Boomer, and neither came close to the brightness of the 90 lumen Serfas. I would not use this light as a main light, but as a flasher combined with a really nice main light it would help with overall safety. Side note: the taillight version puts out far less lumens and there are other more powerful taillights with about twice the lumens for that price. Like one poster said do your homework when it comes to finding the brightest light you can afford, the information is available on the internet with some searching.

  • rick says:

    Think how much brighter it would appear to the drunks behind you if it weren’t pointing down at the ground. It needs a ~18 degree adaptor so it can be mounted perpendicular to the planet. Many other models of blinkies allow for proper installation, why not this one?

    • froze says:

      Have you tried either parking your bike close to the street and then walk away from for about 300 feet to see if it’s bright enough as it is?

      If it seems too dim try adding a 1/4inch thick rubber or plastic spacer of some sort to the underside of the light at the bottom mount, this will allow to tilt a tad more and the band should stretch enough around the spacer but it may be tight. I mounted mine on the fork and used a 1/8th rubber spacer to give it a bit more tilt on the top but it really didn’t need it since I was angling it outward 5 to 10 degrees to increase side visibility.

  • John says:

    Mine has just stopped charging after a year. Looking for the receipt, does any one know, is the warranty just for one year? Thanks. John

  • George says:

    I have this tail light and really like it, have had it a few years now. I use it when commuting as daylight gets shorter and also as a backup to my bigger tail light (DiNotte 400R) when doing night rides. Of course it’s not as bright or long lasting as the DiNotte but for the size of it does a great job comparatively. I certainly feel safe with this light on the back and some reflective clothing.

    It goes on any of my bikes in seconds with the rubber straps. It’s very light and durable. It throws light at a pretty wide angle compared to other blinky lights. The light lasts long enough on high-blink setting for my 19 mile commute and it’s also pretty bright on the lower-blink setting which extends the runtime to more than double.

    It does take a while to charge up, several hours usually. I just put it on charge overnight.

    About the warranty, I recently had a problem with a Serfas headlight that was two years old. Evidently some water had gotten into the light somehow and had corroded the switch. They replaced it for no charge, I just paid for one-way shipping. A friend had this tail light that quit working after a crash and it was similarly replaced. So I would say the warranty service is excellent. I believe there is a lifetime warranty against defects on all Serfas products. I’ve also noticed that accessories and replacement parts are priced very reasonably from Serfas which is unusual.

    I’ve been recommending this tail light to others recently and I see quite a few of them out on the road. Yes, they are a little pricey but personally I think the light is worth the money.

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