Originally Posted by
Fat Boy
If you have any skill with a drill, then get some things called 'riv-nuts' and put 2 in the frame and mount a cage. It won't weaken the frame or anything, in fact it's the way most manufacturers do it.
http://www.mcmaster.com/#rivets/=9kd9ps You don't have to buy them here. A good hardware store with a bunch of the little yellow bins with odds and ends will carry these. Fastenal will as well. Any good shop can do the work for you if you decide it's too much for you. Honestly, no big deal and maybe 10 minutes of work.
sorry, that just screams "stress riser" and "impending catastrophic failure" to me. It might be valid for manufacturers to do that, but they're the ones that designed the frame to begin with and probably had that in mind when they selected/formed the tube. It might be safe on some tubes that are overbuilt, but I wouldnt make that call over the internet.