attaching seatpost acessories to rear of racks?

Question

most night lights are designed to attach to the seatpost. but while carrying a bag on the rear rack that area get's blocked.

some manufacturers sell cheap, awful, lights that attach to the rack (topeak) but i figure some kind of adapter would be much more useful (mostly since everyone may have night lights before getting a rack... i do :)

but my searches for such a adapter failed. do you know any?

This is one example of night light i have http://www.dealextreme.com/p/rechargeable-7-mode-red-5-led-safety-bike-tail-light-with-7-mode-2-red-laser-beam-35mw-90117 (i regret. do not buy, laser is useless snake oil. but the leds are OK)

and this a rack http://www.blackburndesign.com/racks/mtn-2-rack.html (it has a hole on the back, where you can fit a L shaped adapter that holds a reflexive cat's eye)

Answer 1

One possibility is to use extra rubber shims to use the seatpost attaching mechanism to attach to the stay of your rack, like so:

You might be able to use something like the Low down light mount bolted through that hole to give you a little bit of post hanging from the hole and use that with the seatpost mount...

You might be able to mount the hardware without the seatpost mechanism to the hole of an L-bracket mounted in that hole...

With racks with a more serious light mounting bracket instead of just a horizontal hole, I've found many light can clip directly to the bracket with no extra hardware at all, like so:

Answer 2

Cateye seem to have quite a few mounting options including an adapter bracket for a rear rack.
Or you could get a light designed to mount to a rack which many of the German ones do like Busch and Muller.
Then you have the no bracket style lights like the ones from Knog that you should be able to mount to a rack.

Answer 3

If you want something purpose made I know that there are lots of rear lights that come with reflector mounts as included options. For example, here's one from Blackburn.. Look around and read the specs, or ask your LBS for suggestions (there are lot's of crappy lights out there and every shop has their favorite that's proven itself to be durable). There are also plenty ways to rig a light onto the reflector mount of your rack, just use your imagination.

Answer 4

For a lightweight light that clamps to a seatpost all you need is a piece of pipe of the appropriate diameter and some way to clamp it to your rack. I'd recommend about a 5" length of plastic or steel electrical conduit (though buying such a short length may be difficult). Or a length of wooden dowel will work. Clamping it to the rack will require some ingenuity, but if the rack has a reflector bracket attached you could drill holes in the pipe to bolt to the bracket. If there are only mounting holes for a reflector bracket, you can bolt an "corner bracket" to the rack and bolt the pipe to the bracket.

But another option, for the light you have, is to discard the pipe-clamp portion of the bracket and bolt just the actual mount to something. A short length of aluminum "angle iron" would probably work.