The smallest wheels fitted to new Sportage appears to be 16" with 215/70 x 16 tyres, obviously that needs checking, but a wheel size not approved by the maker won't go down well with insurance.

I doubt they will go over the brakes, let alone if offsets etc pair up.

The 215/70R16 mentioned by GB have within <1% the same diameter as the 225/60/R17, so look the right size.

The handbook probably covers the tyre options in terms of load/speed rating of homologated tyres for your model.

mytyres do wheel and tyre sets including winter tyres on steel rims. Between £100-£150 a wheel depending on what winter tyre you wnat fitted in that size.

I actually use some 16" steel wheels with Pirelli Scorpion STR all weather tyres, in winter instead of the far too fancy 18" alloys, on the Outlander. I got those from mytyres after checking with Mitsubishi that the wheel/tyre spec was OK.

The only nuance really was that they said 215/70R16 H rated were the homologated tyre, and all the winters were T rated. Rather than prolong the conversation with them, which they were clearly struggling with, I just opted for the all-season Pirellis which have been fine and have also worn very well.