Driving on a spare tire

About 18.5mm smaller in OD by my calculations, on the Gen 4 with 17" wheels.
Standard wheel: 215/45/17
Skinny spare: 125/70/17.
With 60 p.s.i. pressure in it, might it take up that extra difference and ride higher though ?

 

That's different than our 3rd gen 2010 Prius then. I've placed a regular wheel/tire flat on a slab, stacked the temp spare carefully aligned on top, and checking with a carpenter's square set on the slab and pushed against the tread: there was at most 1/8" difference.

Addendum:

Looked up the Prius c tire sizes in the 2012 Owner's Manual:



And then feeding the above info into a calculator here:

Speedometer Calibration

there is some difference, about 4.5% reduction, going from OEM to spare:



I tried the same exercise with our 2010. The two tire sizes, from the Owner's Manual:





With the stock 15" tire, going to the spare the difference is around 2%:



We have the 17", which has slightly smaller OD, and there the difference is negligible:



Interesting exercise. Summing up, our case (3rd gen with 17" rims) there's only 0.5% reduction, with stock 15" tires reduction would be 2%, and the Prius c though, the reduction is 4.5%.

 

There is something in my Owner’s Manual.