I've had the Garmin Edge 840 for a few weeks now. So far so good - relatively straightforward, loads fast, maps are useful for when you off track. Also has nice feature where you can load real world course from your phone and then virtually ride the course. The edge 840 controls the resistance of your smart turbo trainer to simulate the course gradient.This is my first bike computer head unit.For an in-depth review of this from someone with a lot more experience of these devices, see DC Rainmaker's review (Google 'dc rainmaker garmin 840' as Trustpilot doesn't allow links)

Great--but LOUD--replacement for Edge 1000

I bought this to replace an Edge 1000. The Edge 1000 still works fine, but it's so old it occasionally gets sensor errors with my Varia RTL510.I was a bit worried about the 840's smaller form factor, but this hasn't been an issue. I usually ride with ten data fields showing, and the crisp display on the 840 works great. I don't miss the larger form factor of the 1000.The 840 hasn't had any issues with the RTL510. The battery life is great. It seems to sync with my bike sensors faster. I like the new user interface--it only took a few minutes to get used to.The only thing I could complain about is the overly loud beep alerts--e.g., when the radar detects an approaching vehicle. It lets everybody within a 100 foot radius that something is happening! I've ... MoreI bought this to replace an Edge 1000. The Edge 1000 still works fine, but it's so old it occasionally gets sensor errors with my Varia RTL510.I was a bit worried about the 840's smaller form factor, but this hasn't been an issue. I usually ride with ten data fields showing, and the crisp display on the 840 works great. I don't miss the larger form factor of the 1000.The 840 hasn't had any issues with the RTL510. The battery life is great. It seems to sync with my bike sensors faster. I like the new user interface--it only took a few minutes to get used to.The only thing I could complain about is the overly loud beep alerts--e.g., when the radar detects an approaching vehicle. It lets everybody within a 100 foot radius that something is happening! I've improved this for the time being by putting a couple of small squares of gaffer tape over the speaker holes on the back. Now, the blast radius of the beeping is down to about 25 feet or so. I really hope Garmin lets us control the volume better with a firmware update--I'd like a loud bike alarm, but soft alerts for everything else.

High performance transparent gear

I jumped into Garmin gear with a 530. Have had every version in between. The 840 does exactly what you expect. For me, gear needs to just be transparent and do its job and not worry about it. All the others have seemed to have little quirks that would bug. I had three different 830 and the elevation never worked right. If sweat or over foggy got on the 830 screen it was just a hassle to navigate. The 840 seems to have refined several things. I still hang on to the 530 because it is still a sid great unit that worked without any snags.Garmin makes great gear and there really put out a great unit with the 840.The real time climb is nice and can be adjusted for small, medium, large type climbs.

Love the Touch Screen AND Buttons option

This replaces my 830. I find myself using the buttons on this device more than I thought I would. I love the option of both buttons and touch screen, as I use both in different applications. Setup on this device was very easy, and I like how it paired the sensors that were paired to my 830. The new UI is intuitive with a lot of information. The solar feature doesn't really change the device (maybe like 1/2% per hour when off), but it does help extend the battery. This is a great size for both mountain bikes and road/gravel bikes.

OK, but lots of room for improvements

Negatives: horrible GUI; useless default screens; Power screen gets interrupted by hill screen; Solar screen is not worth the diminished visibility; huge bezel with nothing printed (how about labeling the button functions - I'm all the time hitting the lap button by mistake).Positives; lots of great metrics and feedback, good run time.

Solar Option Makes Device Unreadable

I got the 840 Solar in hopes that it can stay charged for those long gran fondo races. Unfortunately the screen is barely readable in direct sun and with sunglasses on. I could not make out details of the navigation. Brightness doesn't help - it's the contrast that needs to be better. I unfortunately returned this back to REI after this disappointing experience.

Solar is *not* for everyone

I've used most of the cyclecomputers on the market at one time or another. The Garmin Edge 830 was my favorite for a long time, so I've been eagerly anticipating the arrival of the 840. I went with the 840 Solar thinking I'd need to charge less frequently and as the battery aged the computer would remain very usable. What I didn't anticipate was that the screen on the 840 Solar is dramatically dimmer and harder to read than my old 830. I'm really shocked how bad it is, and while I've seen reviews that casually mentioned that the screen is dimmer, they didn't convey the seriousness of the problem. On my 830, I never took my computer out of "auto-brightness" mode and never felt a need to tinker with the screen brightness. It was perfectly fine in my opinion. On the ... MoreI've used most of the cyclecomputers on the market at one time or another. The Garmin Edge 830 was my favorite for a long time, so I've been eagerly anticipating the arrival of the 840. I went with the 840 Solar thinking I'd need to charge less frequently and as the battery aged the computer would remain very usable. What I didn't anticipate was that the screen on the 840 Solar is dramatically dimmer and harder to read than my old 830. I'm really shocked how bad it is, and while I've seen reviews that casually mentioned that the screen is dimmer, they didn't convey the seriousness of the problem. On my 830, I never took my computer out of "auto-brightness" mode and never felt a need to tinker with the screen brightness. It was perfectly fine in my opinion. On the 840 Solar, with auto-brightness on it's difficult to read indoors or outdoors in late afternoon conditions. Don't get me wrong: It's not like it's illegible, but it takes more focus and attention to read than the casual glance that works with every other popular computer in the marketplace. I have to set it in manual mode and crank the brightness just below the battery consumption warning level to have a reasonable result. This is all without wearing polarized glasses by the way: I can only imagine how bad the experience would be with them.If Garmin released a software patch that made the auto-brightness brighter on the solar models that would help a bit. It would also consume more battery power, and you have to wonder how much of the extra power you're getting from the solar cells is going right through to the backlight. The bottom line is that the "Solar" option should be treated as a niche product and never a no-brainer. If you need every drop of battery endurance, refuse to charge from an auxiliary battery, ride in extremely bright conditions, and you're pretty indifferent about screen brightness, then this is probably a good choice, but I definitely wouldn't recommend it for the average rider.Outside of the solar/display brightness issues, it seems to be a decent (if uninspiring) upgrade. I haven't done empirical testing, but the computer seems to run faster, so for example, the latency between shifting gears on an electronic system and seeing the gear display update feels improved. The UI is not fantastic, but seems a little nicer to navigate , with a similar feel to the inReach Mini 2. Having both touchscreen and side buttons together is a welcome change. USB-C is long overdue. It is disappointing to see that Garmin hasn't added any new data field layouts, and the lack of organic Tyrewiz support is lagging the competition. If you're looking to get a first serious cyclecomputer, the non-solar 840 is probably going to be a solid choice, but if you have a 530/830, this is largely going to be a matter of incremental improvements.

Solar is a bust

Pros:- Seems to be more responsive than 830- UI is easier to navigate than previous iterations- Buttons + touchscreen is a welcome change.Cons:- Solar option makes the screen way too dim, doesn't add much charge at all. This is essentially a niche option for people who value charge time above all else and don't want to use any kind of external power.- No organic support for Tyrewiz

Worthwhile Upgrade From The Garmin 810

I've had my Garmin 810 for almost 10 years and decided to upgrade to the 840. The difference is night and day. The 840 loads up fast and the setup was super easy. It has a wifi auto-sync so it will upload to Garmin Connect and Strava the second I'm back home and near my router. Some cool features I liked on my first ride were the climb warning that let me know a hill was coming up and the tight turn warning. It shows how long the hill will be, how much longer I had left to climb, and the current grade of the hill.My only gripe with the Garmin is out of the box the memory was full so I had to delete the EU maps to update it. Also, the auto-brightness seems a little too dark. Both of these are easy fixes in the menu. Overall it's a worthwhile upgrade.

climb

So far like the climb feature. Adding buttons makes the 840 complete, use in all conditions, gloves etc. Only problem so far is one restart during a ride. The computer just turned off and restsarted by itself. When it restarted it asked me if I wanted to finish the ride. The computer recovered my position and continued routing the ride but it did not reord any further ride data. Overall I really like the computer but Garmin needs to update the firmware to continue recording data once the gps has resynced.