I took two 8x4 sheets of plywood and then cut them down the middle the long ways. That made a shelf that was 16x2. It's a good depth, and probably the best fit for not hitting the garage door rails.
Hi,
My Name is brad, and I was looking at an older thread you had replied to, http://forums.mtbr.com/singlespeed/finished-garage-bike-rack-finale-133802-2.html about the bike rack that you built for your garage. I am about to do the same this weekend, and was wondering what debth you made the shelve come out from the wall ? and now that it has been a couple years since having it did you make any changes to it or would you suggest any changes? Much appreciated. Brad.