I can't really beat Mike at the internet. He's on this jag to win the internet next year and he goes and writes about beer, and pros, and what beers the pros drink. Real substantive stuff that edifies the reader. Actually, who am I to knock beer? No one, that's who.
Anyhow, I have a simple test for blog posts: I tell my wife the general gist of the post topic when we are going to sleep. If she falls asleep within the first 7 or 8 seconds, then I know that it will be a great bike nerd topic.
All of this is preamble because this post is short. My last soporific story to my wife was about tubular gluing (she who will never have to worry her mind about tubular glue went to sleep in record time), not this. But we get SO many questions about using specific brake pads and "do I REALLY have to switch out the pads I've been using with my aluminum rims for the last three years before I use my carbon rims" type entreaties (the specific answer to which is a categorical yes), that I feel like people must be going about swapping their brake pads the wrong way.
First, you're going to keep the pad holders on the bike. Do a quick check to make sure that the pads actually contact the rims when you squeeze them. Good? Good! Then loosen the quick release on your brakes so they are in their "wide" setting. Now, take your tiny ass little hex wrench (1.5mm in most cases) and loosen the set screw that's on the outside of the brake pad holder. Loosen it until it almost comes out, but doesn't. Next, if you are doing the front pads, turn your bars almost 90 degrees to one side. Then, take a needle nose vice-grip, and adjust it so that it grips firmly but not punitively onto the brake pad (NOT the pad holder), clamp the vice grip onto the pad from the rear of the pad, and pull. Et voila! The pad is out. Next, take the new pad, grab it with the vice-grip in that same orientation, and push it in. Et voila! Now tighten the little set screw on the side. Done. Repeat for the other pads.
When you finish all four, take a quick check to see if all four pads hit the brake track on the rim when you squeeze them. Some rims are a bit bigger diameter than others. Most brake tracks are 10mm or more tall, which is taller than brake pads, so you've got some tolerance, but you don't want your brakes to be hitting your tire. That's not good for anybody.
I switch back and forth between pads for carbon and pads for alloy rims all the time, and maybe I'm just lucky but I almost never get brake squeal. I don't set up for toe-in. My pads hit the rims flat. This works well for me. And my FSWs and RFSWs and RFSCs all work with the brakes at the same height - no adjustment needed.
It's never a bad idea to give the pads a quick brush with sandpaper each time you swap them. Emery boards work great, and just a quick pass, then rinse and dry. If they're really skanky, dish soap and a toothbrush, then the emery board, then rinse and dry.
Also, pads are right and left specific. You have to keep that straight.
By the time you do this a few times, it takes less time than such fun things as:
- swapping wheels
- changing a flat
- pumping up a 29er tire with a floor pump
...and many others!