If you're someone that tends to get lost, the idea of turn-by-turn directions on your bike can be very appealing. However, until now, I haven't found a good solution.
Google Maps briefly had a hack where you could export directions to your phone - but it got shut down. Garmin Edge devices have the ability to upload maps, but folks I've talked to tell me it can be finicky to get the maps set up and you often have to use a 3rd party service to set up the directions and turn points. Strava has an interesting route creator tool in Beta - it uses data from other peoples' rides to help you find the most popular routes - but on the phone, it is best used for verifying whether you're on route or not rather than actually directing you.
RideWithGPS has for a while now been my favorite tool for creating routes on my PC. It is fairly intuitive, it follows the roads well, it knows when a road is good for biking or not and will automatically re-route if you try to get on a freeway, and the cue sheets it creates don't tend to have a whole bunch of repeated steps.
On a recent extended ride, I decide to give their subscription phone app a go. For $6 a month (or $2 for a 3-day one-time trial), it promised turn-by-turn directions. And guess what? It works.
Seriously, this thing is really solid. You set up the route on your PC using their main site with all the benefits and features I described earlier. Then you save it and it pops up on your phone as available route. Open the route and click the arrow button and you have turn-by-turn directions.
Even better, you can also download the whole route to your phone - so the maps and the directions - so that when you're on your ride, you don't have to use phone data to keep updating as you go along. This has the triple benefit of meaning that you can save battery by switching off data, you can save money if you have limited data by doing the download on wifi at home, and you can survive even if you're in an area that doesn't have phone data.
Once you start the navigation process, you'll see a map that tracks where you are using your phone's GPS. As you approach turns, your phone makes an alert tone, a voice describes the upcoming turn and the description shows at the top of the screen. The alert tone and voice also still work even if your screen has switched off, making for even more battery saving.
I used the app for a three day, 200 mile ride from Vancouver to Seattle and it worked a treat. The only issue we had was with a trail that turned out to be a mountain bike trail - and that was more a limitation of my route mapping (I was using Strava heatmaps to guide me where to go and unfortunately, that tool does not differentiate between road routes and mountain routes). I was able to use the RideWithGPS map to find a detour and then it told me with a happy tone when I was back on route. The app also gives you an angry tone when you get off route and it tells you how far and in what direction you're off your route.
There are, as with all such things, some limitations. The directions are only as good as your mapping - as per my experience with mismapping a mountain trail. It also does not automatically re-route - if you're used to google maps in your car, when you make a wrong turn, it reroutes to figure out the best way to go from where you went wrong. RideWithGPS does not do that - instead it only tells you that you left your route and gives you hints as to how to get back. And finally, it is a battery hog. Since it is using your GPS at all times, it will definitely consume power. You can minimize it by downloading your route before you leave home and then you can turn off phone data which will save a lot of battery. You can also set up the app to have the screen mostly turned off. But even with those, you're going to go through your regular phone battery fairly quickly. I solved this by buying a larger battery for my Samsung Galaxy phone that gives me a lot more life ($30). If you have a phone that doesn't take replacement batteries, such as an iPhone, you could get a USB battery extender, although you'd need to find a way to attach it to the phone while you ride.
Speaking of attaching, to get the most of this app, you're going to want a mount to put the phone on your handlebars so that either the screen is visible or you can hear the alerts and turn instructions as you go. Amazon has lots of them for about $30.
So there you have it. I really like this app and feel like I got $6 worth of use from it in my first month of using it. I even used it again this morning to follow the convoluted turns of the SF2G ride down the San Francisco peninsula. I am not sure if I'll keep my subscription for ever more - it might be something that I switch on and off at times when I know I am going somewhere different that the roads I know, but heck, maybe I'll keep the subscription to reward the company for making an awesome app.