I had trouble putting a rear fender on my favorite bike because of the clearence between the tire and the brake arms.
You run into this problem on bikes that were designed for performance, i.e. not commuting.
I didn't want to use narrower tires. I was already forced to run 700X25 tires when I usually go no narrower than 700X28. So I decided to just split the rear fender into two pieces at the brake bridge on the frame and then bridge them with a narrow piece of metal.
It ended up working really well and not looking as bad as I thought it might. So far it hasn't made any noise although I just did put the fenders on today and I have only rode 10 miles with them.
Step 1: Rough Fit and Cut Fender
Rough Fit and Cut Fender:
Step 2: Prepare P-Clip and Fender Segments
Prepare P-Clip and Fender Segments
Step 3: Attach Fender Pieces
Attach Fender Pieces
Then bolt the other side of the p-clip to the post of the bolt you just attached to the other fender segment.
Then attach the rear segment of the rear fender as you would normally install a fender. TIP If you're bike frame does not have eyelets for fenders than you can attach the fender stays to the seat stays of the frame with more p-clips, like I did.)
Tighten a zip tie around the brake post of the brake and the pclip bridge you just installed. Make sure the zip tie is tight because the is going to be what prevents the bridge you just made from vibrating on the brake and making noise.
NOTE: I also installed a front fender which I did not go over because there was plenty of clearance for it.