I have used my Etrex GPS units on the bicycle for several years now and have always been dissatisfied with the handlebar mount supplied - it is too flimsy and, on some units, it allows significant vibration which can switch the unit off. It also only fits on the handlebar and I would have preferred a stem mount.
I therefore set about making a bomb proof tough mount for all eventualities.
Herewith an account of the mount build process - pictures are mobile phone pictures and so not brilliant but adequate to show the results...
Scouring the interweb, I came across the RAM series of GPS mounts - originally designed for motorcycles. GPS Warehouse
stocks them and I bought a couple of these to butcher into shape - I did not buy rail clamps - most of them being designed for motorcycles and add too much bulk and weight.
This is how they are supplied, together with a set of fixing nuts and bolts which I discarded into the spares tin...
And this is what it looks like without the wrapping before being butchered. Top side first...
and the bottom side. You will notice there is an oblique diamond shaped mount area which usually bolts onto a mount.
The other bits of kit required were:
1. A semi round rasp
2. A small piece of high density foam. I used a piece of central heating pipe insulator foam cut in half. This has the advantage of being pre-shaped...
3. 2 decent weight zip ties - use re-usable ones of you want to swap the mount from bike to bike.
4. 4 mm drill or narrow pointed soldering iron. (not shown)
Method:
First lay the mount on a surface bottrom side up and use the half round rasp to file away at the mount along its long axis to create a wide mounting groove - if you want a handlebar mount, do it short axis. This is what it looks like after a few minutes of gentle and meticulous filing:
and
Next drill or melt two new holes at the other corners of the mount - I find a fine tip soldering iron gives a lot more control and produces an acceptable result like so:
Next lay the HD foam in the right place and pierce with the zip ties - just pushing the sharp ends through at the right spot work very well - no need to cut or drill. Start from the outside push through to the hole, loop the tie over to the other hole and push through from inside out. You end up with it looking like this:
Now simply place on your stem (or handlebar if you have a short axis groove) and tighten the zip ties:
Voila!
(If you want decent quality pictures, let me know and I will brave the -5C outside and do a better job in daylight)