I'm by no means an expert, but my experience with BaseCamp, my Zumo 660, and sharing routes with a friend's 660, is that several things can contribute to the unit's recalculation of the route so that it doesn't match what you planned.
Bear in mind that some of these things can interplay with one another.
If the mapset on the computer and the mapset on the unit are not the same, this can cause routing issues. Don't ask me why; I don't understand mapsets. Roads that have been where they are for 100 years should route the same in the latest and greatest mapset as they do in a five-year-old mapset. But sometimes they don't.
Avoidances set in BaseCamp not being the same as avoidances in the unit. This seems to be a sure and certain way to mess things up! If you set BaseCamp profile up to avoid major roads but don't do it in the unit, the unit may re-calculate to take the major roads.
"Shortest route" vs "Fastest time" setting. This one can be a bit confusing, as ofttimes the route we want to take is neither shortest nor fastest.
The easiest way to combat all of this is to set up the route in BaseCamp with enough via points (using the rubber band tool) that the unit has no choice but to follow your intended route. I call this the "Big Hammer" technique and we all know that you can fix anything if you have a big enough hammer. Or at least beat it into submission. Lacking in finesse, I choose to carry a big hammer.
Now, you say that the unit recalculates the route and ignores some of the way points you've put in. I've never heard of that (it would seem to violate the basic routing algorithms in the unit) and so can't offer any help. Things that would seem to violate the way the damn thing is supposed to work have happened to me in the past and, when I've been able to figure out what happened, it boiled down to operator error or I really hadn't done what I'd thought I'd done.
Play with the rubber band tool and via points, then load the route to your unit and see what happens. You'll get a feel for when you've put enough via points/way points in. The thing you have to remember is that, no matter what else you've done, the unit wants to find either the fastest route or the shortest route. There's really no setting for "Do what the heck I told you to do". Overkill on via points won't hurt anything.
Also, there are a few ways to get your route loaded onto the unit from BaseCamp and, apparently, the unit's behavior is somewhat dependant on how you do that.
First is the Export function, second is the "Drag and Drop" method. I've had more success with "Drag and Drop" than export - With your unit connected to the computer you should be able to see it in BaseCamp. Take your route that you've built and drag it down and dump it on the "Nav V" and let it copy to the unit.
Third would be to export a .gpx file to a card, insert the card in the unit and import it, while fourth would be to export a .gpx file to some location on your hard drive and use File Manager to move it to the unit. These methods are usually reserved for (by me) for sharing routes either in the field or by e-mail.
I don't really understand the inner workings of the route transfer, but I think it's JimE who does. Hopefully he'll be along to provide a clear description of how to transfer the files with less likelihood of recalculation. I'm more of a guy who kinda sorta knows how to use the fool things, but doesn't really know how they work. I know that magic is involved.
Eric, Tom's advice is spot-on.
A couple of things:
Unlike the 660 vintage units, the Nav V wants to "import" all new routes into its Trip Planner. I haven't done any tests to see if it truly recalculates when doing this or not. I believe it does, though.
In any event, I strongly advise that the correct approach is to do your routes in such a way as to ensure that they will withstand recalculation
, rather than trying to avoid recalculations
There are at least three reasons for this:
1. I rarely ride a route without something changing during the route. Missing a turn, deciding to deviate from a planned route to go to a barbecue place for lunch, deciding to drive through the scenic overlook, stopping at a Walmart to grab some chapstick...you know what I mean. When I do those things, I want to be able to let the unit go ahead and recalculate me back to my planned path, or perhaps I need to search for one of those places and let the Nav add that to my route. I don't want to have to set the Nav to "no recalc" and essentially do without its help while getting to/from those diversions.
2. That's a good QC step to make sure that you haven't missed with any of your vias or shaping points. It's very easy in BC to get a point just off the road, and that can introduce some bizarre routing. Once the route has been moved to the Nav, I like to step through all of the turns and look for anything strange. You can (and should) do that while still in BC as well. Katnapinn and I were looking at a route just the other day, where we had dropped a via on the service road on the wrong side of the interstate. The routing had us exit, make a U turn, go to the next exit, make another U turn, then re-enter the freeway...obviously not what we had intended.
3. If you want to share the route with anyone else, you need to make sure the route will work the same way on their unit. Getting the file to them and onto their unit will almost certainly involve a recalculation, and they will likely have a different map set than you do.
So as others have advised, the key is to set your preferences and avoidances consistently between BC and the Nav, and to use enough vias to ensure that the route does not change upon recalculation. Unlike the 660-vintage Zumos/Navs, the Nav V nicely honors shaping points (vias set to "don't announce in BC), and it also has larger capacities, allowing you to have more vias/shaping points per route; so use them liberally.
I have found that when testing this stuff and doing many iterations of moving routes to the unit, that it's very easy to get confused and not be able to distinguish your latest trial route from a previous one...it will do things like put a " 1" on the newer ones and that can be off the edge of the screen on longer names. So my advice is to make sure you delete everything off the Nav and just move the routes/waypoints of interest at that time. Keeping your data well organized in BC lists is also important to keep from getting confused.
If you have a specific route that's giving your trouble, export it to a gpx and post it here, or shoot me a PM and I can take a look at it and we can figure out what's going on.