Tire size calculator
try this site to compare different sizes...will tell you the % the speedo will be off...
but even the OEM sizes vary a bit from each of the 3 (15, 16,17) oem rim choices...
175 is stock width on a 15' cooper rims...stock rim width 5.5
195 is stock tire width on a 16' cooper (optional rim), stock S, 6.5 width...
Many of us, including myself run 185 on 15'rims for winter tires (on a S).....
one tip...going wide change how the cars feels...same for heavier rims...
Wider also changes MPG a bit..more rolling resistance...but you gain a bit of grip...so depends on the driver.
How wide of a tire you can put on a specfic rim will vary a bunch depending on the sidewall of the tire.....heck some folks make a game of it with terms like "POKE" and stretch..can be an interesting look...
you can look up the manufacturers recommendation for rim width..they list a MIN/MAX and IDEAL.....
My suggestion.....the cooper is a bit low in the HP department...so go to wide..and it will feel slower in the straight line...but more grippy in the corners....so choose carefully...and the speedo will go further off....
the 185 size mentioned is almost the exact size match for the oem 195/55r16...so works out well...many tires are in that size at a cheaper price than the 175 size...so the speedo is within 2-3 MPG of correct with a gps....
not sure I answered your question....but got you some info anyway!!
Like x 1
