Exposure Sirius Mk9 Daybright bike light review

Considered the entry into 'proper' road lights the Exposure Sirius Mk9 Daybright bike light is powerful, high quality and a bit of an investment.

Exposure Sirius MK9 Daybright bike light
(Image credit: Exposure)
Cycling Weekly Verdict

The Exposure Sirius Mk9 Daybright bike light is a wonderfully tactile and superb piece of functional engineering at its finest. Power output and beam pattern and it's hard to beat. Add in the Sirius' versatility and it represents almost the complete package, but for some it will cost prohibited..

Reasons to buy
  • +

    Build quality

  • +

    Beam power and pattern

  • +

    Versatility

Reasons to avoid
  • -

    More expensive than many of its rivals

  • -

    Bracket won't fit aero bars as standard

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The Exposure Sirius Mk9 Daybright bike light is the gateway light in the brand's road range and is aimed at all road users. It’s by far the smallest light in a comparison with similar power lights in terms of physical size and weight but it manages to pack a punch far better than all of its rivals.

>>> Best bike lights: best front and rear road bike lights (opens in new tab)

Exposure manufactures all of its lights in-house in the UK and the build quality is exceptional, backed up with superb customer service that should ensure your light lasts a lifetime. I personally have Exposure lights (opens in new tab) that are still functioning flawlessly after twelve years of constant use and abuse.

Bike light mounts

The light mounts to the bar using a simple plastic clip and rubber strap. It's a system Exposure hasn’t changed for well over a decade, that’s how well it works.

Unfortunately the as standard the strap isn’t long enough to fit aero bars so you will need to factor in an additional band when purchasing the light if this applies to you and your bike. These are only £5 but it does add to the initial, relatively high, outlay.

>>> Exposure's 2021 lights are here with boosted brightness and featured updates  (opens in new tab)

Talking of additional brackets, the Exposure Sirius Mk9 Daybright bike light that can also be used as a helmet light, again you need to purchase the right mounting bracket. It then becomes an excellent light for venturing out on the gravel bike, enabling you to put the light wherever you’re looking, giving it great versatility. 

Flashing Vs Steady

Operation is via a rear mounted button and offers a traffic light system to indicate which mode is engaged, it then switches to indicate battery level.

The Exposure Sirius Mk9 Daybright bike light uses the brand's own OMS programmable mode setting to enable the end user to set the power and number of light modes dependent on preference.

A long press of the button engages the Daybright flash mode, recommended for daytime running (opens in new tab), a setting that harnesses the full 850 lumens and is hard to miss even from a significant distance.

The best bike light?

The lens of the Exposure Sirius Mk9 Daybright bike light focuses the beam into a super bright spot that over shines all other similar lights when compared. This is surrounded by a good spread of light on the peripheral to enhance road and hazard perception, while also delivering excellent side visibility.

The only downside is that charging is via a dedicated cable rather than the usual universal USB-B cable. This might put some people off as it means you need to carry a dedicated cable rather than rely on the usual one that everyone has everywhere. But the upside is that the charge port is well protected from the weather, as long as you insure that the fiddly rubber cap is shut properly. 

If your budget allows, then the Exposure Sirius Mk9 Daybright bike light is top picks, with it's versatility and well know durability future proofing your riding.  

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