Comparison of tire sizes 305/65 R17 and 265/65 R18
305/65R17
305
Tire width 
65
Profile height 
R17
Tire diameter 
384
RPM per km 305mm198mm828mm2602mm
305
65
17
265
65
18
| Parameters Sizes | Old | New | |||
|---|---|---|---|---|---|
| Diameter, mm | 828 | 802 | -26 (-3.1%) | ||
| Width, mm | 305 | 265 | -40 (-13.1%) | ||
| Circumference, mm | 2602 | 2519 | -83 (-3.2%) | ||
| Profile height, mm | 198 | 172 | -26 (-13.1%) | ||
| RPM per km | 384 | 397 | +13 (+3.4%) | ||
| Clearance change, mm | -13 | ||||
| Result: | The diameter differs by -3.1%. | ||||
| Speedometer reading (km/h) | |
|---|---|
| Real speed (km/h) | 96.8 |
| Difference (km/h) | -3.2 |
Sizes for comparison of tires 305/65 R17
R17
R16 -1
R18 +1
Sizes for comparison of tires 265/65 R18
R18
R17 -1
R19 +1
R16 -2
R20 +2