275/55 R17 doesn't belong to the most popular dimensions for summer tyres - there are 8 tyre models available, which can be compared to 160/70 R17, 205/40 R17, 195/40 R17. Let's break down the sizing - 55 is height of the tyre, which is calculated as 55% of the tyre width (275mm), which means the sidewall height has 151.25 mm. The wheel diameter is R17, which means it fits to a 17 inch/431.8mm diameter wheel. The total circumference of the tyre is 2306.87 mm, which is very similar to 205/80 R16(2307.19 mm), 235/75 R15(2304.36 mm), 235/70 R16(2310.33 mm), 285/35 R21(2302.47 mm), 295/30 R22(2311.58 mm), 285/40 R20(2312.21 mm), 235/65 R17(2316.3 mm). There are multiple speed indexes available for summer tyres in 275/55 R17: H(210km/h), V(240km/h). The same goes for weight indexes: 109.