Wheels & Tyres

Yes, that seems reasonable, and 205/55 R16 is certainly close enough.

Be aware that there are only a few millimeters clearance between the stock tyre's inner sidewall and the front strut. You may need some small spacers to avoid rubbing.

For efficiency, the rolling resistance of the tyre will play a much larger role than the overall diameter. It's a shame the US tyre labels don't show this, but thankfully EU labels do. I recommend trying to find EU labels for the exact models (including size, speed rating, and load rating) so you can make an informed comparison. Sometimes, the rolling resistance can vary for the same model of tyre across sizes, speed ratings, and load ratings.

The tire dimensions--especially section and aspect ratio--play an important part as well. This is clear from the Engineering Explained video "Why Big Wheels Are a Bad Idea on Electric Cars--Range Impact!" I too have a favorite Ultra High Performance A/S tire that worked miracles on my Honda Fit Sport but might not be so great on the Mini SE's 16-inch wheels for several reasons. One is that it doesn't come in 195/55 size and although 205/50 might fit fine, I worry about range impact. Secondly, the SE has no spare, so run flats are specified as the only Mini Star rated tires and unfortunately the few A/S run flats do not perform reportedly as well as their non run flat relatives--especially in noise and tread wear--not to mention snow. Mini is supplying summer tires to boot, expecting us to swap seasonal tires. I'm not going that route. Not storing tires and wheels. It's a bit of a conundrum but at least it keeps me occupied while waiting for delivery.