Well normally 10" wide rims are suited better for the likes of 33X12.5's. Do they look like the sidewall goes "in" from the rim to the tread?
With the rim being wider than the tyre they'd be more likely to pop off the bead when normally driving let alone wheelin.
I'm sure someone will say "they'll be fine", put it this way, I wouldn't
If you were going to a bigger tyre later the go for it, but a 31X10.5 should really be on an 8" rim (in a perfect world)
Mine however are on 7" but I couldn't get White spokes here in an 8". 1" in is better than 2" out
BTW I (not for much longer) work for Firestone here in NZ (7 years), that's where my $0.02 is coming from