very strange they put a 48/36/28 on it isnt it? Why not a 26 at the least??

that aside, a 22 may go on with no problem, probably yes, but any good bike store can slap one on in less than 5 mins and then they will know, if not, go with the 24. In either case, its a cheap change and will be very useful on horrible hills when you are knackered.

re 14t jump, I ride with a 13t jump and its not too bad, I have ridden a bike with a 16t jump and it worked but you had to shift up at least 2 gears when you'd go to the granny--but who cares if you get easier gears going up with loads of stuff on the bike.

a 22 or 24t chainring will cost $25 perhaps, perhaps more like 30-35, but really its an easy change and doesnt affect your regular cruising mid ring or downhill 48 ring.

as for top speed, a 48-11 is ample and I would wager that top speed down big hills comes much more from having the safe conditions and experience to get really going, and any gearing is going to run out past 70 or 80kph anyway, so its a moot point the small differences that are being argued about (and more a question of being comfortable at speed and judging when its ok to go really fast)

And yes, who can hold 40 or 50kph on the flat on their own--no one in my opinion and certainly not for long--but your 48-11 will still allow you to pedal along at 50k down a long mountain descent, which is nice sometimes and keeps the legs moving.

ps, about a 22 or 24t ring, go into some bike stores and ask what they have, you will see how one 24t will cost $25 and another racing light one will cost $60....so ask around, any steel cheap one will be fine, who cares if it weighs x grams less than another, and steel will last longer.