I recently acquired a Surly Steamroller (fixed gear bike). I want to ride is as a single speed for everyday use. I changed out the rear wheel and got one with a flip-flop hub. I'd also like to add a rear brake but I'm not sure what will work. The Surly website states that standard reach post mount calipers are compatible but that's for the current model. My bike is a number of years old. The other problem is that there are no stops for housing. Any suggestions for my best option(s)? Thanks.
The steamroller will work (for the last 5 years at least) with a standard reach rear brake. Any model will do. As for housing stops, you must use a full length housing, and zipp tie it to the top tube of the frame, or have someone add riveted stops. Full length housing is easier, cheaper, and doesn't void your warranty.
You can pick up any low-cost standard-reach rear brake. In a pinch, some of the models from Nashbar work. You can zip-tie or run cable clips to route your brake cable. Be sure to acquire a long length of cable housing.
I recommend not adding a rear brake, you should add a front brake instead, and learn to use it properly. Any standard reach front brake should work fine.
If you want to have both brakes, then use the full length housing and zip ties as others have mentioned.
The complete bike as specd by Surly has a front brake only.