Garmin

This Edge 840 is a very good upgrade to the Edge 520 it replaces. I've ridden with it for over a month and have these observations.

- Battery life is greatly improved, with many more rides between charges.

- Display is larger on a similar sized device, permitting more stats while maintaining readability.

- Touch screen controls easier to navigate than buttons, especially during a ride.

- Improved map details, which includes road and traffic alerts.

- Fewer false incident detection for urban riders. Much of my ride is in urban landscape, with rapid stops that triggered incident detection on the Edge 520.

This is one of those, 'didn't know how much I needed this,' purchases. The radar picks up cars further back than your ears can hear. I feel much more aware of what's behind me at all times. Can't imagine riding without it.

It works well with my Wahoo Bolt 2, though it doesn't remember my preferred flash settings (takes 15 seconds to configure pre-ride).

Battery life is fine. I can get several rides out of one charge if I'm only doing flash alerts. If I'm also using it as a persistent rear light it needs to be charged by the end of the ride.

Included seat post mount uses silicon bands to secure. Better clamp-based options out there.

I did a lot of research before buying a "fancy" bike computer. For years I had a simple bike computer that gave me cadence, speed, etc. But, with my new bike, I wanted something with GPS and routing capability. Garmin 840 does all that and a ton more. When it comes to devices, I've been trained to believe that either devices are ultra customizable or they work well. This device somehow manages to do both! It has a massive amount of capabilities and customizations and yet it works flawlessly. For example, it automatically found my SRAM AXS components, bike radar and uploads routes from my phone or computer quite seamlessly.

Highly recommend this

Between my wife and I, we have owned every version of the Garmin 800 series GPS. When my 810 died I bought an 830 for the front of our tandem bike. When we bought a second tandem for another location, we bought 2 more 830s for the front and rear because my wife, the stroker, also likes to have one. When her 820 died recently after many years we bought her an 840. This one is probably more capable than its predecessors but more complex to program due to the confusing menu system. Not to mention the 3 extra buttons. We don't use most of the available features; just navigate courses given to us on group rides. This unit has way more capabilities than we need, but it does what we need with a nice bright color touch screen and beeps that are louder than previous models, which makes them easier for old ears to hear.