Saddle Ai Alert 250 Rear

The Lezyne Saddle Ai Alert 250 Rear is a rear bike light that lives under your saddle and tells the traffic behind you when you are slowing down. It detects deceleration and, when you brake, changes to Active Alert: a rapid 250-lumen flash that works like a car's brake light. The body is fully CNC-machined aluminium, it weighs 73 g, and the Ai Alert software comes pre-programmed and collects no rider data.

Who it's for

Road riders and commuters who share the bitumen with cars, and who want the driver behind to see the difference between a cyclist cruising and a cyclist stopping. Picture the run into a set of lights on the Gold Coast Highway at dusk, or the bunch braking hard on a descent in the Scenic Rim: the light changes its output to signal that you are slowing. Mounting to the saddle rails also frees up the seatpost for a saddle bag or a second light.

Brightness and runtime together

Seven modes plus the Active Alert brake flash:

• Day Flash 1: 250 lumens for 15 hours
• Day Flash 2: 125 lumens for 25 hours
• Blast: 80 lumens for 4 hours
• Pulse: 50 lumens for 8 hours
• Flash 1: 50 lumens for 34 hours
• Economy: 10 lumens for 20 hours
• Femto: 10 lumens for 60 hours
• Active Alert: 250 lumens, triggered by braking

For daylight rides, Day Flash 1 runs the full 250 lumens for 15 hours on one charge. After dark, Flash 1 at 50 lumens keeps going for 34 hours, and Femto stretches to 60 for a multi-day tour.

Beam shape

Ten LEDs sit behind Wide Angle Optics that spread the light across 270 degrees, so the light shows to the side as well as directly behind.

Charging and battery

The light unscrews from its saddle-mounted body to charge, so the mount stays bolted to the rails. It holds an 1100 mAh battery and charges over USB-C; bring your own cable. A small indicator shows charge level, green from full down to 75%, amber to 25% and red below that.

Mounting

The mount clamps standard dual-rail saddles, including 7 mm round rails and 7 x 9 mm carbon rails. The rail hooks can face up or down to suit your saddle, the light should sit parallel to the ground, and a T25 key tightens both hooks evenly to 3-4 N m.

Weather resistance

Rigorously tested to IPX7 waterproofing standards and built by Lezyne to perform in demanding weather.