22mm on the brake side, 24mm on the sprocket side. Removing and installing was just posted in another thread today. Basically it goes like this:
Jack up bike, remove brake caliper, loosen rear axle, take the tension off the chain by screwing in each adjuster, remove axle, remove chain, then roll the wheel out from the bike.
The caliper mounting plate will want to hang loose and put strain on the brake line. Support it out of the way. Clean and grease the axle and spacers before re-installing. While you have the wheel off, inspect the cush drive rubber for wear(it's inside the wheel behind the rear sprocket). Be sure to retract the adjuster before axle/spindle removal or re-insertion.
The tricky part isn't removal, it's when you re-install everything. I'll toss out Moe's tips from an earlier thread:
When replacing the rear wheel, set a 2by (lever) under the wheel with a block of wood (fulcrum) under it. Place the spacers within the seals, put the chain on the sprocket, and get the wheel close to the spindle holes. Then place the caliper plate on. Now you can work the spindle in from the left then use the lever to raise the wheel for the other side. It does help with the task.
The caliper plate is installed last with the spindle holding it in place (partial insertion of the spindle).
My 2 cents: I'd put the chain on before installing the spacers.
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Getting the caliper plate, the spacers, and the chain tension adjusters all lined up to put the axle through can be a tedious task. It helps a lot if you put new grease on the spacers which allow them to stick to the seals. It's not a glue-like stick, but should be enough to get the axle through before they fall off if you're careful. Having somebody to help by holding the tire while you get the axle through is also a good idea, IME.
