Originally Posted by DRTBYK
I have found that not all GPS's support turning off Auto Recalculation. The zumo 660/665 can import routes in two ways. One way will convert the Track to a Route but there are no limits to the track point count and again Recalculation has to be set to OFF. The other way to import is via the Off Road Tracks feature. Here tracks have to be filtered to a max of 650 points and you can only have 16 tracks in the library at a time - although unlimited can be held on the µSD Card. I still only provide Tracks since I can filter them to the lowest "common" level usually 500pts. But, it really comes down to what works for your needs.
Yes, I like the Off Road Tracks feature of the 660/665. That method pretty much makes them like the rest of the line in terms of being able to accept a track. While there is technically no limit the other way, what happens is if the track exceeds a maximum number of points ( I think the early Zumos were 225 points or so), the unit creates its own via points in substitution for blocks of track points. When that happens, the unit will use auto routing for that segment regardless of whether it's turned on or off. So that can yield some really strange results. The Off Road Tracks is the way to go, and 650 points isn't too bad, though not as good as the 376's 1,000 points. Of course you get to have an unlimited number on the card that you can import, so that's a huge bonus.
In our GPS tours, we provide waypoints and routes as the main form of navigation, and back it up with tracks. We can do some things that way that can't be done navigating a track alone. However, some folks prefer to follow a track no matter what the caveat, and they can still do that with our tours if they wish. Like you said, it comes down to individual needs and preferences.
Thanks for helping me troubleshoot this strange phenomenon guys! I'm not giving up yet on figuring out what the particular limitation or event is that causes the problem to arise, and will report here on whatever I find (or don't).