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Portland Design Works Gravity Plus 100 Rear Light Portland Design Works Gravity Plus Rear Light
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Portland Design Works Gravity Plus 100 Rear Light

Mfg PartNum:446
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Portland Design Works' Gravity Plus Tail Light has a built-in accelerometer that detects deceleration or swerving and automatically changes to a super bright, solid beam to warn following traffic. To allow the accelerometer to calibrate, always install the Gravity Plus on your bike before powering it on. Hold the power button down for 1 second to turn the light on or off. Then, keep your bike still for 1 second after pressing the power button to complete the calibration.

The Gravity Plus Tail Light has redesigned mount that works with the included seatpost and seatstay brackets.


  • Automatic accelerometer brake light function shines 100 lumens bright.
  • USB rechargeable li-polymer battery.
  • Weatherproof exterior for all season riding.
  • Mounts vertically or horizontally.
  • 2 Modes (runtime): Solid - 20 lumens (12 hours), Flash - 80 lumens (30 hours).
  • Weight: 1.9 oz.
  • Includes brackets for seatpost and seatstay mounting and Micro USB Recharging Cable.

B-Stock - This product has one or more B-Stock units available. These units can be purchased at a discount (see option select). B-Stock units were returned from other customers and may have missing or damaged packaging materials. These units are otherwise as new. The full manufacturer warranty applies. Click Here for more information.

Light Type: Rechargeable 

Ordered by Most Relevant First
5 stars
4 stars
3 stars
2 stars
1 stars
Reviewed 12/2/2019
Cycling Enthusiast
Portland, OR
Value Rating
Overall Rating
Please bring back the USB Danger Zone!

I previously owned a PDXDW USB and non-USB Danger Zones. The non-USB was great, and the USB was the best rear light I've ever owned. This seemed like a similar set up when I bought it. Having owned it for over a year, I can say it's very disappointing. The output isn't nearly as good as the DZ. It just feels cheap all the way around. It always seems to switch to the wrong mode. Every time I ride I have to verify whether it's on the right mode or not. Looking for a replacement ASAP.

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Reviewed 5/13/2019
by Keith B
South Florida
Overall Rating
1 of 1 customers found this review helpful.
Awesome product

I have several 50 plus mile rides using this light so far and have not recharged it. Very happy with the battery life and durability so far.

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Reviewed 4/23/2019
by Anonymous
Cycling Enthusiast
Kirkland, WA
Value Rating
Overall Rating
2 of 2 customers found this review helpful.
Very disappointing

I was initially very excited about this light to use when my wife and I are riding together to help us signal to whichever one of us is behind that the one of us in front is slowing down. However, we discovered that on anything but super smooth, flat roads the light went into the super bright warning mode extremely frequently. After a few rides, one of the two lights pretty much stays in this mode constantly and eats up its battery in the process. I have given up on these lights and bought different lights instead.

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