Originally Posted by
genejockey
My understanding is that DA and Ultegra allow adjustment of brake lever free stroke, but 105 does not. I have the same issue on my Canyon, that over the 1500 miles I've ridden it, the free stroke has increased, especially at the front. I THINK what's happening is that as the pads wear the return springs are still pushing the pistons back to the same place, so the free stroke increases. It's a little disconcerting when I switch from my rim-brake bikes, because I like to keep the pads close to the rim so I get bite with just a little lever travel.
I know people will tell you that disk brakes are supposed to be self adjusting, but I think that's if there's no return spring, like in cars. I should take pictures of the gap when I change pads and then look at it a couple hundred miles later.
Unless the pistons are sticking, the gap should stay consistent throughout the range of pad wear. If you're seeing more lever travel than before, and if the lever isn't really firm, I'd suspect a little bit of air in the lines. Is this one of the stable that gets hung on the wall pretty regularly? Hanging it with the bars down or, heaven forbid, both wheels up, could certainly encourage reservoir bubbles to work in to the lines.