Here's an exploded view of my homemade Nuvi mount (clockwise from bottom left):
1) Original ashtray insert that came with my E90. Lined with the fuzz ("loop") side of self-sticking velcro.
2) A few pieces of velcro stuck back-to-back, so one side of this is the "hook", the other side is the "loop".
3) A base plate made from a scrap piece of plastic (e.g., expired credit card) with velcro sticking to both sides, similar to 2).
4) Original suction mount that came with my Nuvi. Since the suction cup in my mount is too worn to stick to anything, I removed the cup (gently punch out the metal pin that hinges the lock down lever) and lined the exposed bottom with velcro. If your suction cup is in good shape, replace 3) with a smooth piece of scrap plastic (e.g., CD jewel case cut to size) and apply velcro to one side only. Leave the other side for the suction cup to hold on to.
Here are the steps to make the mount:
1. Line the inside of 1) with self-sticking velcro. I recommend using the loop side, so in case you want to use the ashtray to hold coins it will have a velvet-like lining.
2. Layer up 2) to "fill" the curvature of the ashtray insert. The idea is to make the curve flatter so 3) will stick better.
3. Mount 4) onto 3). The base plate provides a flat surface for the suction mount, and spread the load to a larger area of layered velcro. You may need to trial-and-error for the best fit.
4. Install the assembly to the car. Adjust to fit Nuvi between the console, the shift lever, and your knee.
Here's some observation, pros and cons, after a few months with this mount:
Pros:
1. It cost very little ($0 for me).
2. It makes no permanent modification to the car. Easily and completely reversible (a hair dryer will help remove the velcro lining from the ashtray insert, if you must).
3. The base plate and layered velcro provide good support and stability for Nuvi.
4. The mounting location is right next to the lighter socket. No dangling wires. Nuvi is very easy to power since it uses standard USB charger. I use a generic one (shown in a previous picture) because it has a short and coiled cord.
5. The location is close at hand if you need to use the touchscreen.
6. The location is low enough so the summer sun in a parked car is less likely to harm Nuvi. Lithium batteries in GPS don't bake well under the sun. I've killed a few windshield-mounted GPS this way. It is one primary reason I wanted a lower mounting location.
7. The screen is less of a distraction at night.
8. The location doesn't block anything of the car (it may slightly block the driver's seat heater button if you have ZCW).
9. The location allows a short and tidy cable to the AUX input if you want Nuvi to play MP3.
10. The silver color of Nuvi's face kind of matches the shifter. My unsuspecting friends thought the Nuvi came with the car (the BMW logo in the splash screen helped, too
).
11. And best of all, you can pull the whole shebang out with the ashtray insert still attached, throw it in the glove compartment, close the ashtray lid, and no trace of a GPS ever been there.
Cons:
1. The location is a little low if you need to look at it a lot.
2. The space between the console, the shifter, and the knee is limited. Nuvi (both the receiver and the mount) is compact and fits just fine, but other GPS may not fit as well.
3. I like to fold Nuvi's antenna out of sight, so the low location does affect reception slightly. It may take a little longer to lock onto satellites. It worked well in downtown San Francisco but I have not tried it in other urban canyons. You may need to tilt the antenna horizontally or upward to get better reception, if your terrain is difficult.