Bald Paul

Rode the "Bee Buzzin' Tour" in SC yesterday. I had created the route from the PDF map and cuesheet provided on the event website in Garmin Connect and uploaded it to my 830 (software version 8.10)
Everything was fine until I made the left turn at the red arrow on the map. As you can see, the route took us up a road to Lake Greenwood, where we looped around and came back on the same road to continue on.
As soon as I made that turn, I got an "Off Course" notification, with a "Make a U-Turn" instruction. The unit appeared to be confused by the fact the route returned on the same road, and was trying to send me back. I continued up to the loop (the road was marked with arrows) and suddenly, the unit basically told me (not in these words, of course) "Well, if you're not going to follow directions, I'm not going to navigate at all!" and stopped all navigation. When I got back to the turn at the end of the road, I continued onto the first rest stop following the road markings, had to save that part of the ride, re-load the route, and tell it not to navigate back to the start of the route. It picked up the remaining route instructions, but of course, my total mileage, average speed, and elapsed time displays were all messed up.
Evidently, this has happened to several others on out and back routes. I think the software is trying to calculate the shortest route (which would cut off that section of the ride) but I can't find any setting in the navigation menu to change that. The only options you have in Routing Preferences are "Minimize Distance", "Minimize Time" and "Minimize Ascent". It seems you have to pick one, you can't turn them off. :-(
Any suggestions? (p.s.: Garmin support is no help)

Edit: more reading. I did turn Route Recalculation to "Off". Maybe that's the trick!

Iride01 

Maybe it thought you turned too early or some other thing that confused it.

Sometimes zooming in as far as you can might let you see some discrepancies in your actual track and what the route is.

But that's an after the fact thing. For prevention, I've no idea other than always know the route better than your GPS does.

Bald Paul

It's raining here today, but I'm going to create a local route that has an out and back section, then upload it to the computer. I'll see what happens with the Route Recalculation turned off.

dorkypants

When I was using Garmins I found that on any route where there's a significant section where you're going one way earlier, then the opposite way later on, the device is likely to get confused and direct you to turn around. My workaround was to break the route into separate segments to avoid these overlaps. The downside, of course, is that you have to remember to switch to the next segment as you reach the end of the one you're currently following.

I found route recalculation to be more of a hindrance than a help because as soon as you went off course it would revise your route to get you back on course. But if you wanted to backtrack to where you went off course it was difficult-to-impossible as it no longer had your original course.

rm -rf

I've never tried Garmin Connect routes. I always use ridewithgps routes. My planned routes with out-and-back U-turns in the route always work on Garmins. (I can't think of any out-and-back failures.) I have a 1030, other riders have 830s, and both work. My biggest complaint is that there's no distinction between "Make a u-turn 1.3 miles" from the actual route itself, or an off-course "make a u-turn 1.3 miles" message. I sometimes try to put a short turn onto a side road at the u-turn spot, just to get a turn message and avoid confusion when riding.

Figure-8 routes don't always update the real-time map in time to show the correct turn, when the route comes back via the same road then turns in a different direction on this second pass.

It's good to keep in mind the approximate mile marks for these route overlaps, so it's a bit more obvious that complications are nearby.
~~~
One time, as I was heading out of the parking lot and following a route, I briefly turned back, and it announced "Route Complete" as I rode past the finish line. Grrr.

NOTE: you don't have to stop and restart the recording, just go to Main Menu-->Navigation and select the route again; navigate to start-->no. It'll keep recording but update your route. This also works when you want to shortcut a ride or switch to the 60 mile instead of the 100 in the middle of the ride.

Steve B.

Yes, Garmins can get confused on out and back routes. My 1030 has done this. The device knows its on a course that is in the other direction and cannot seen to figure out the course goes 2 different directions on the same road, One issue I learned to pay attention to was where I placed control points when I drew the map, so as to put them on opposite sides of the roads. This helps prevent the confusion.

As well and in your case I might have just turned off navigation, especially as you knew this leg was an out and back, then maybe restarted when you got past the turn intersection.

Part of me though is puzzled why you had a navigable route for THIS course. There's one turn and one turn around. I don't think I would have bothered.

Bald Paul

The map shown is only part of the route I rode. As I said, I had to restart the route at the first rest stop, and finish the rest, so the entire route isn't shown.
I programmed in the out and back part because I wasn't familiar with the area and didn't want to miss the turn. The route was marked on the roads at turns, but several people missed them because they were small.

Steve B.

Now I understand.

unterhausen

I live in a valley, so it's very common to go out and back. My garmin 800 used to get really confused about that. Interestingly, it always worked in situations like the OP's, even small out and back excursion worked okay. I think it is the recalculation, don't let it think and it will do better.

Machoman121

Pro Tip - Disable auto Recalculation. When the unit recalculates it will delete your installed route and perform a complete recalculation to the destination - generating a new route. So a re-route ( recalculation) is asking the unit to produce a new route to the destination - even if it's a small detour. 9 out of 10 times the recalculated route is laughable. Have the original route permanently loaded on your unit and do a self manual detour around to arrive at your loaded route....or stop and load your original route again and get the unit to take you there to the route (not to the start of the route). Basically the unit doesn't do dynamic re-routing. It recalculates for the entire route, not parts of it.

njkayaker

There aren't any real differences in the files produced by the different route planners.
It doesn't matter which one you use.

pdlamb

I did a new route last month where I had similar issues. On the road, I checked the map (the displayed route was correct) and kept going. Eventually the GPS caught up with me, though sometimes I had to put up with a few minutes of beeping (GPS) and bleeping (me).

When I got home I zoomed way in near those anomalies. They were associated with waypoints that weren't quite right: 5 feet into a parking lot, 10 feet in a field near a gravel track, that sort of thing.

Best advice I have is (1) put waypoints 25 feet after a turn instead of at an intersection, and (2) leave recalculate off unless YOU want it to give you a new route.