Reviewed: 2025 Trek Ion 100 R & Flare R City Bike Light Set

Bike lights are an absolute necessity. No matter when or where you ride, if it’s on the road, you should have lights — day or night. I still keep in touch with the Trek team who brought their first DRL’s to market and I thank them every time for keeping me and millions of other riders safer on the road. The all-new Trek Ion 100 R and Flare R City Bike Light set adds

Trek Ion 100 R / Flare R City Bike Light Features:

• All-new models launched in August 2025
• Specifically designed patters with daytime visibility up to 900m away
• Package includes front and rear lights, mounts and USB-C cable
• Flare R has 40% more runtime and Ion R has 36% more
• Visible battery status LED’s
• Integrated side lights add visibility
• Blendr mounts available for various placements
• 2 hour charge times
• Ion 100 R: 100 lumens (day steady – 2 hrs), 5 lumens (low steady – 24 hrs), 100 lumens (day flash – 11 hrs)
• Flare R City: 20 lumens (day steady – 5 hrs), 2 lumens (low steady – 21 hrs), 35 lumens (day flash – 10 hrs) , 2 lumens (night flash – 24 hrs)
• MSRP: $84.99 (full set)

Easy lights for riding or commuting

There are a myriad of daytime running lights on the market, but none of them have been able to unseat the venerable Trek DRL’s in my testing. Cannondale and others have tried to integrate lights into their frames and other light manufacturers have tried to match what Trek brings to the table, but they just aren’t cutting it. For 2025, Trek re-launched their urban-focused Ion and Flare lights with a new design and added firepower.

For starters, the battery capacity has increased exponentially — thus making them last even longer between charges. And, charging them is even easier with USB-C (can’t wait until everything adopts this). If you’re commuting with the Ion/Flare DRL’s, that USB-C is easily topped off in the office. Knowing when it needs a charge is also a cinch with the onboard, full-time fuel gauge. This 4-bar LED light is much preferred over the old single LED where you could go from green to red faster than you’d think. And, I can go for multiple rides and it’s only depleted by one bar.

The Ion 100 R and Flare R City are made for commuting, but I say hogwash and have been using them on the road and gravel just fine. Perhaps the Ion 100 R yields a little bit of aerodynamics, but I’m beyond something as minimal as that. It’s a great light and can be easily mounted with the versatile rubber strap or using a Blendr mount underneath a compatible out front computer mount.

Speaking of mounts. The standard mount actually works well and has proven to be reliable for many years of use. Just make sure it’s locked in place before heading out (easily done). Popping them back out is just as easy.

Turning them on and changing the modes are easily done. Long-press is on/off and a single-press changes modes. You don’t have to learn any fancy steps or click your heels just right. The large power button is also great. Validating the proper mode up front is as easy as placing your hand in front to confirm. There rear can be done the same way, but is a little trickier. This comes in handy when switching from one mode to the other as it gets lighter or darker.

The rubber mounts keep the lights in place not the bars or seatpost quite well. Even after a rough gravel track, the Flare R stays put.

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