Now that I have the Varia radar, I would not want to be without it...it really does change my comfort level on the roads I ride on regularly. My challenge is that unless I was running a really small seat bag, I simply did not have enough seat tube to mount it anywhere but way down by the seat clamp. While it did seem to report traffic fine there, I was not satisfied with the warning lights for traffic itself so I felt like was getting only half the benefit of the radar/light combination. (And for those who say forget the seat bag, for some reason, I seem to have a pathological resistance to carrying a bunch of stuff in my jersey pockets...when I fondo, I prefer to keep most things in a larger seat bag like I show in the picture and just a few things in my pockets.)
I looked for rail based alternatives and even considered ordering the rail based Varia mount from www.racewaredirect.com but that would have interfered with my extra bottle holder in the rear of my larger seat bags so I came up with a way of mounting the post clamp on the rear of my Selle Italia Superflow seat...nice and high.
To do this, I had to make a couple of alterations to the stock mount:
1) Since I was mounting it horizontally, I drilled two extra holes in the mount so I could turn the quarter-mount 90 degrees.
2) I used the smaller of the post pads and shaved a bit of material off the back of the pad so it would fit snugly over the new screw positions and the zip ties would pass through.
3) I used a coupe of zip ties to secure it to the rear of the seat. It held fine with one zip tie but with two, I have a bit of redundancy and I could snag them under the band mounts.
Walla...high tail light with minimal interference with my various bags. (I can even use it with my Relevate Terrapin...although I kinda wish there was a decent quarter-turn mount for the tabs on the back of most bags.)
Take a look...maybe this will solve some of your mounting challenges if you like using a seat bag (and have a flow type saddle).
