I have found this Mapset displays the OpenStreetMap mapset on Garmins pretty good. The level of detail at different zooms is good. The map background is white as opposed to green which is easier to see on the bike in my opinion. There are different versions of the mapset you can download, The basemap is less cluttered, the DEM(Digital Elevation Model) version show 3D type topography. There is a request for a small non compulsory donation to the contributor for the work to create and update the mapset. Registered Users also get additional benifits for a small yearly donation.

If you place mouse over map type name at downloads page you'll see a short description of each type. They are described in more detail below:

• OSM Base Map: Map for general use. It contains roads, streets, tracks, paths and POI among other elements. Most appropriate for nüvi series satnavs.

• Topographic map: It contains the same information than base map plus contour lines, which will give you information about terrain height and steepness. Suitable for outdoor activities, such as hicking, mountaineering, etc. Contour lines can be activated or deactivated as needed.

• Map for Trucks: Map specially designed to be used in trucks, as it considers weight, height, etc. restrictions affecting these vehicles when calculating routes. Elements without importance for these vehicles have been removed from the map, to make it clearer. +Info

• Base map with DEM: Map is rendered over a Digital Elevation Model, which enables showing hill shading, calculate route profiles and show 3D maps. +Info

Choose whether you require the IOS or Mapsource file. Once you have downloaded the file it's just a matter of opening the file with Garmin MapManager and then installing on your Garmin Device with Garmin Map Installer as normal.