Tyre Upsize Tool

Tyre upsizing is a good way to enhance the performance and looks of your vehicle. But installing too big tyres on your car can sometimes negatively affect the handling. Tyre upsizing also results in the speedometer error. As a general rule, the diameter variation between the two tyre size should be under 3%. We have built this easy to use tool for you, just enter the size of your OEM tyre and the tyre size you want to upgrade to:

tyre readings for upsizing

How to Read Tyre Size?

The tyre size, load rating and speed rating in mentioned on the sidewall of the tyre. Example: 185/65R15 88T. Let’s see what these markings stand for:

1) Tyre Width: The first three numbers here represent tyre width in millimetres. In the above example, tyre width is 185mm.

2) Aspect Ratio/Profile: This number is used to gauge if the tyre will be high profile of low profile (height of sidewall). It is represented by two digit number after the slash mark. This number is the ratio of height of tyre’s cross-section to its width. In the above example, the tyre profile/height will be equal to 65% of 185 (tyre width).

3) Type of Tyre: There are 3 types of tyre construction: Bias Belt, Diagnol cross-ply, and Radial. The “R” letter here stands for radial tyre.

4) Rim Diameter: The two-digit number after this represents the diameter of the rim on which this tyre will be mounted. In above example, rim diameter is 15 inches.

5) Load Index: The next two-digit number after space tells the load rating on the tyre.

Tyre Load Index
Tyre Load Index Chart

6) Speed Rating: The Speed rating of the tyre is represented by the letter at the end. The speed rating of the tyre should always be more than the top speed capability of the car. In the example, the speed rating is represented by “T”.

Tyre Speed Ratings
Tyre Speed Ratings

Common Tyre Sizes Available in India

12 inch 13 inch 14 inch 15 inch 16 inch
145/80R12 145/80R13
155/65R13
155/70R13
155/80R13
165/65R13
175/70R13
185/70R13
155/65R14
165/65R14
165/70R14
165/80R14
175/65R14
175/70R14
185 R14
185/60R14
185/65R14
185/70R14
195/60R14
195/70R14
175/65R15
185/60R15
185/65R15
195/60R15
195/65R15
205/60R15
205/65R15
215/70R15
235/75 R15
31X10.50R15
195/55R16
195/60 R16
205/50 ZR16
205/55R16
205/60R16
215/55R16
215/60R16
215/65 R16
215/65R16
225/50ZR16
225/55R16
225/60 R16
235/60R16
235/70 R16
245/70 R16

 

17 inch 18 inch 19 inch 20 inch 21 inch
205/45ZR17
215/45R17
215/50ZR17
215/55R17
215/60R17
225/45ZR17
225/50 R17
225/50ZR17
225/55 R17
225/55R17
225/65R17
235/55R17
235/60 R17
235/65 R17
235/65R17
245/45R17
255/60 R17
265/65 R17
225/40ZR18
235/40R18
235/45R18
235/60R18
245/40R18
245/40ZR18
245/45R18
245/45R18
245/50R18
255/45R18
255/55R18
255/55R18
255/55R18
265/60R18
285/60R18
245/40R19
245/45R19
245/45R19
255/50R19
255/50R19
275/35R19
275/45R20 255/50R21

265/40R21

275/30R21

275/35R21

285/30R21

285/35R21