Whats up guys, I was looking on buying these rims off my boy, but I don't know if they will fit my IS350 2015 F Sport. He says they are 19s, but could not tell me the dimensions for them. I looked online and I saw they had to be 235/35-19? Thanks in advance

 

From the tire sizes I would guess the 235/35/19 is on a 19x8.5 rim (which potentially could fit the IS).
The 275/30/19 is likely on a 19x10 rim (which potentially could fit the IS).
Without any offset numbers, it impossible to tell if these will fit your car.
The tires are the right size for aftermarket 19's for an IS, but that's about all I can guarantee.

If you look at the back of the rim, do you see any markings as to size or offset?
What brand/model of rims are they?
What did they come off of?