17.5 tires on a stepdeck

[Hammerhead]

Are you really going to need them? How often do you really need a step that low is what I'm asking.
Compared to a 275/22.5(523rpm) @ 60mph, the 17.5 would be doing the equivalent of 76mph worth of tire revolutions.
They're a 55mph tire, actually rated at 62MAX. They spin 662 rev/mile!
That's an extra 139 rev's per mile, or 76,450 revolutions per 550 mile day!
Do a little math and figure out how many more miles a 275/22.5 would get with a week's worth of tire revs...do you really need to be that low?

I know several guys using them in specialized applications.
Carry spareS! The plural S was capitalized for a reason. When they start to wear funny, they can peel off in no time.
You say you want a spread step, if you do and you go with 17's pretend you're one of us long as hell multi-axle units...take wide sweeping corners, they don't like $-hook turns.
Oh, and don't bump curbs, the sidewalls are too small to flex and absorb it, you'll cut them. So make sure those spared are mounted on rims, cause you may not find them when you have to.
Any weight savings will be wiped out by the spareS you need to carry.
The brake shoes/drum contact area is smaller, so braking isn't as strong as standard braking. And they get hot fast, and brake fade is more prevelant.
Brake shoes and drums wear out faster too, and parts aren't always available.
They don't have a long life expectancy, so get used to buying tires often. The tire shop owner will send you Christmas cards...you may even get invited to come enjoy his new swimming pool, lol.
They don't do well in the heat, so if you're on nice black pavement over 100°, you can run with me...at 45-50ish mph.
If you're not doing something specialized, I wouldn't advise it.