I've had several trailers that ran the 17.5's, have two right now that have them on as well.
I'm not sure if your aware of this or not, guessing you are, but 17.5's are run on smaller axles, the brakes are much smaller than those on 22.5's.
The only reason to ever buy a trailer with them on is to save critical deck height when something is loaded.
I have no idea what your hauling, how far your going at any one time, how heavy your loaded at all times and what time of year your running, but I'd opt for 22.5's any day of the week and twice on Sunday.
The issues with 17.5's we've had are these, everyone stocks 22.5's, hardly anyone stocks 17.5's and nobody will stock the brand you like to run and buy, those will be special ordered every time.
The smaller brakes and drums heat up much faster, causing brake fade much quicker, this in turns heats the rims faster and on hot summer days, translates into blown tires much faster especially if your loaded close to max weight on pavement.
I'll second that continentals are the best 17.5 bar none, nothing else comes even close for tire life or wear capabilities or will withstand the heat of summer.
Brake issues and wear are much higher with 17.5's by far, same goes for costs to repair or replace anything brake related, drums are replaced much more often with the smaller drums verse the larger ones, over centering of the cams happens much sooner with the smaller brakes, as they say in the same given distance driven, those 17.5's are higher cost per mile in everything compared to 22.5's and the larger brakes and drums.
I don't know if they make the smaller brakes and drums in outboards or not, I've only ever had inboard brakes and drums in 17.5's, its certainly something to ask about, any brake work is so much easier with outboard brakes, and also cheaper.
With the smaller brakes and drums comes more brake adjustments due to the shorter throw of the brakes to begin with, your window of adjustment is also smaller, so once adjusted cold you have to recheck them warm, most times they will heat enough to be set too tight once heated up and driven.
I have no idea if its in the brand of pads used, but I've never had a brake pad spit off the shoe on a 22.5, those you wear down to the rivets almost, but every 17.5 I've ever had, would spit the pads off the shoes long before they were worn out, nobody stocks anything I've ever had for the smaller brakes on 17.5's, those are always ordered and you wait or you run them with some pads spit off the shoes till the new shoes come in. One trailer I had was so rare we'd have to take my worn out shoes in and have new pads put on them, then wait to get them back again.
Not sure what else your wanting to know about them, I could type pages of things we've had issues with involving 17.5's and unless the trailer is so much cheaper or loaded height is that critical I'd avoid them myself, 22.5's will be much cheaper in the long run. Best of luck on whatever you decide.
