| As you slide the calipers off of the disk, you can angle them and as a result push the pads (pistons) back in the calipers. This will give you enough room to remove the calipers.
It is a tight fit though and you may want to put some tape on your rims to prevent scratching them with the calipers when you're removing them.
When re-installing them, you will probably need to use a screwdriver to push the pads back to give you the clearance required.
Care and patience and you'll be fine.
Tim | 
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