Confused about what that letter means right after your tire size? Ever had someone at a tire shop ask what your speed rating was and didn't know what the person meant? Don't know whether you need the more expensive V- or ZR-rated tires that the car came with? Fear not, mighty consumer, for the information here will edify you. Definition of Tire Speed Ratings A tire's speed rating is an indication, expressed as a letter code on the tire sidewall, of a speed the manufacturer expects the tire to be able to sustain over a long period of time without coming apart. This is good information to have for a number of reasons, some of which actually include the likelihood of you ever being able to sustain even the lowest of speeds that passenger car tires are rated for.The speed rating code is semi-alphabetic and goes like this:B: 50 kph 31 mphC: 60 kph 37 mphD: 65 kph 40 mphE: 70 kph 43 mphF: 80 kph 50 mphG: 90 kph 56 mphJ: 100 kph 62 mphK: 110 kph 68 mphL: 120 kph 75 mphM: 130 kph 81 mphN: 140...
