I have a stock 2014 MX-5 GT with OEM 17” rims: 205/45-17. The tires are near the end of their useful life. I find the ride a bit harsh with lots of road noise. Looking to possibly charge the tire size to 205/50-17. Will the tires fit without rubbing?

 

They will most likely fit without rubbing, however, you'll experience speedometer and odometer error in exchange for virtually zero improvement in the ride. As for road noise, that is far less of a factor of tire size than it is rubber compound and tread pattern. The following tire has a very good reputation for being less harsh and far more quiet than most on the road and is available in the 205/45 R17 size:

• Continental ExtremeContact DWS 06

 

Can anyone confirm if a 205/50-17 tire will fit on a 2014 Miata MX-5 GT on the stock 17” rims?

 

205/50R17 will fit a 7J rim, but changing from 205/45R17 to 205/50R17 will raise the gearing by 3.3%. This will also raise the car's center of gravity by 10.25mm. For more comfort it's better to fit 205/50R17 to a slightly narrower 6.5J rim, rather than the 7J rim.

If you're looking for much better comfort, then it's best to change to a 16" rim and a tire size that has more sidewall.

Perhaps a 195/55R16 tire size fitted to a 6.5Jx16 ET50 5/114.3 67.1 rim.

The 195/55R16 has a much higher standard load index than 205/45R17. Therefore, you can drop the tire pressures by about 0.2Bar (3psi) when using 195/55R16 compared to 205/45R17.

Load index of tires
195/55R16 87(545kg)
205/45R17 84(500kg)

As you can see in the chart below, there's only 0.7% difference in the outside diameter of these two tire sizes.

Outside diameter of tire
195/55R16 620.9mm (+0.7% bigger than 205/45R17)
205/45R17 616.3mm

6.5Jx16 ET50 5/114.3 67.1 steel rim
​​​​​​https://www.oponeo.pl/wybierz-felgi-...p3vA+N62QlOTfg