Specialized Flux 800 Bike Light Review

The Specialized Flux 800 is a go-to mountain bike light with a wide beam that covers more than enough trail.

The Specialized Flux 800 (now, Specialized Flux 850) is a go-to mountain bike light.

It sprays a wide, rectangular beam that covers more than enough trail. And while the max power setting runs for less than two hours, the middle settings provide all the light I need with double the runtime.

Specialized Flux bike light specs

  • 800Lm max brightness
  • Runtimes: 800Lm – 1.75hrs, 300Lm – 3hrs, Flash – 20hrs
  • Weight: 183g
  • Mounts: Helmet included, handlebar sold separately
  • Price: $90 MSRP
  • Buy from Specialized and Jenson USA

With just 300Lm in the two narrow or wide mid-settings, I have enjoyed multiple fall night rides with this bike light alone. The “narrow” beam is plenty broad to see the edges of the trail while looking far enough ahead, and as long as the descents aren’t too long. For the fastest trails you can click it into high mode.

The primary reason I have enjoyed the Specialized Flux 800 light so much is that it comes with a helmet mount right out of the box. There’s no need to remember to purchase one, and I don’t have to keep track of the handlebar mount that I’ll never use.

The foot of the mount is padded to keep it from scratching the helmet shell, and the accompanying velcro strap is long enough to fit on almost any half-shell helmet. The angle of the light is easily adjusted just like an action camera mount, so you can find the precise angle that works for your helmet.

Like several of the bike lights reviewed, the Flux 800 from Specialized is powerful and inexpensive enough that folks could purchase two of them, and keep one fully charged in a pack or on the bars in case the battery runs low.

Pros and cons of the Specialized Flux bike light


  • Comes with a helmet mount
  • Select from wide or narrow beam
  • Convenient all-in-one form factor


  • Battery life may be lacking for longer rides

Bottom line

With its simple attachment, fantastic luminance, and reasonable price, the Flux is among my favorite mountain bike lights tested.