Here is a great mount for the Garmin Nuvi. Excellent value on a heavy duty handlebar mount that fits handlebars up to 1 inches. We even include rubber strips so that this mount can be used for much smaller handlebars.  This can be easily removed. This uses the cradle that came with your GPS.

We also include a hardwire power cable that will fit your GPS (mini USB).  

This is all you need to hook up and ride!