I bought mine a couple of weeks ago on their current sale for $415 (down from $639) which seemed like a great deal. I haven't made us of it but if I referred someone and they bought one, they get a HRM free as well (and I get $25), which is even better.
I was not sure if I would like it, but it should be a risk-free purchase because they offer a 45 day trial period with free return shipping if I don't like it.
It arrived on Friday 9th June and I charged it up and spent some time setting it up. The setup was pretty easy although a bit of checking on the Hammerhead website to find out some "how to's" because as is usual now they is no manual to speak of. They don't use an app - instead the unit connects directly to the internet via WiFi and everything is stored in the cloud.
My previous GPS was a Bryton 410 (been using it for 3 years, 2.3" monochrome screen and a smaller Bryton for 2 years before that), so the Karoo 2 is quite a significant change. A large 3.2" high definition (about 4 times the pixel count of similar sized Garmin or Bryton units) colour screen - I find it broadly similar in quality and responsiveness (and size) to my old iPhone 4s (which I dug out & fired up just for laughs). It is not as responsive as my current iPhone 14 Pro but that is no surprise, but it is a LOT better than most cheaper touchscreens. Even at 25% brightness it is PLENTY bright enough to read on a sunny Brisbane morning - I might try drop it down to 15% and try it out.
The number of screen layout options is vast - mixes of maps & data, maps only, data only (with a variety of data options from about 3 fields to I think 12 fields per page). I have tried the navigation on my regular route and it beeps and shows turn pop-ups as it should. It seems to be accurate to within a couple of metres.
I created a map of my regular route 3 ways - in the Hammerhead web-based dashboard, using RideWithGPS and by saving an actual ride as a route. All were easy and upload within a few seconds.
The Auto-Pause was initially taking too long to initiate (because it takes a few seconds for the speed to drop to zero), so I changed it to start the pause when speed dropped below 5km/h and it now works well. At the end of a ride, it pauses, I stop the ride, choose to save or delete it, and if saved a few seconds later it appears on my Hammerhead dashboard (uploads over the home WiFi).
Twice I have had it start and say "No cadence sensor found" but when I checked the sensor page, it found it and everything worked fine - still not sure what this is about ?
Battery life is probably the biggest criticism of the Karoo 2 online and that is something I am monitoring closely to see if it is going to be a deal breaker. I never do long rides but I also don't want to be charging every few days either. My Bryton 410 was giving me about 18 rides (about 45-50 minutes long each) on a charge.
I charged it after last Saturday's ride (my first ride with some mucking around) and have been on 6 rides in the last week. The rides were 45-50 minutes each and total about 280 minutes (4 hours 40 minutes). One of them was using full navigation, but it didn't actually seem to consume any more battery than just riding with a data screen. My main data screen has 11 fields plus ride time, actual time of day and battery percentage displayed at the top of the screen (so 13 ride parameters on one screen and all are easily readable). I also have phone notifications turned on. It drops by about 6-7% per ride and is currently sitting on 61% battery left after 6 rides.
So, assuming I only took it down to 10% of battery left, I should get about 11 hours of riding or about 14 of my rides which is certainly worse than my old Bryton 410, but probably not terrible considering it is a much larger and more detailed screen and the device has vastly more features. Perhaps, like many lithium battery powered devices, the battery life might improve slightly after a few cycles ? Once I have done a full cycle I might try reduce the screen brightness a bit more (to 15% maybe) to see how it performs - I did see reports online of people using 5% brightness with good visibility (but maybe not under Australian sun
).On the whole, I am liking it so far though I am not using anywhere near the full feature set so far. It is certainly a big change to my old Bryton so a lot to get used to still, but nothing too quirky. The battery life could be better but it doesn't seem terrible so far.
I think that for $400, it is a very well speced bike computer with undoubtedly the best screen in the business. It undercuts the similar Garmin 1030/1040 and Bryton s800 large touchscreen units by a significant margin. I wouldn't have paid $640 for it though.
Fancied something yesterday called a SILCA Ti bidon cage, in noice bourbon colour: $128.99 each (!) 
At least it's a tad cheaper than a Garmin 1040...
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