I'm running Ultegras. They are tight getting a 25 in and out with the cam open, havne't looked to see just how close the clearance is in the top. I assumed I'd need to rims because I'm pretty sure I could not get an inflated 28 on and off and still have the brakes adjusted.
But why do you need to remove an inflated wheel/tyre.
If you puncture it is flat when you take it off and you inflate it when it is on again.
For maintenance it isn't a big deal to let it down a bit and reinflate.