Agree with others that those aren't "serious" luggage - still got 29" ones in our basement. But, traveling could be a bit easier - IMO ...
Food for thought - personally, 1 roller plus 1 carryon w/o wheels, and optional small bag if necessary - 2 rollers on wheels is max for me - 3 is a challenge thru IAD and SFO making connections, and on the return - regardless of carrier. Corridors at IAD and SFO are very, very long & challenging to navigate with a roller in each hand - at a fast pace (unless connection is plentiful & not rushing to avoid missing the final boarding call ...)
Assumed that this all on a single UA ticket (or Air China code-share) - SFO-PEK is on a 747's and should be fine, what about FLL-IAD and IAD-SFO? If your flight is full, gate agents might restrict "all" pax to one items onboard and gate-check the rest (most recently doing transcon - both DL & AA offered it free to speed up boarding as there simply isn't enough overhead bin & floor space in front of the seats to store all the pieces boarding) Items with wheels tend to be singled out more readily, bulkier & heavier. Are you flying Y or Y+ or up front in J and will you pre-board with status/zone 1?
Carryon looked like a wide-body and should be fine in OHB, within 45" linear measurements for a typical 22" MLC case. The 2nd. personal bag is defined by UA as a shoulder bag, backpack, laptop bag or other
small item (no larger than 9 inches x 10 inches x 17 inches, or 36 linear inches)
I would take out the tape measures but my hunch is that yours might be over or it's very close as it looked fully expanded. Are you taking a 15" or 17" laptop plus gadgets/accessories?
Is the 26" monitor staying behind in China after a presentation or a gift to someone, and not flying back afterward? Even tagged as fragile, there's no guarantee that it will safely arrived in working order without cracks or damages.
How long are you staying in China, bring less & find a way to do some laundry during your stay, think outside the box for a moment. It's the joy of traveling light, even when going overseas
This is my personal bag, from Eddie Bauer - small & fit easily even for regional jets, but expandable if necessary. I now travel mainly with 11.6" Sony netbook & Nexus 7 tablet (sometimes, I will go with the "bigger" Dell 14" notebook & iPad) and I got everything covered, with room for medications & energy bars/snacks/nuts & crackers. Most of the gadgets fit tightly inside a small or slim eBag packing cube, depending on how I arrange items - with room for a tall 16 oz. coffee themos, my favorite personal piece on the road. Fully loaded but heavy, but FA barely blink as I pass them "sling" over the shoulder (with a fully sized 22" carryon for domestic, int'l - I checked only one piece & bring an extra/zip-out fleece jacket for the cabin.
