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Question:

questions about buying tires?

Hi everyone. I got some questions regarding tires that I need answered. I need to replace the tires on my infiniti, but need some info on how to buy proper tires. The tires I got on now says P215/55R17 93V.So my questions are: 1) If I buy tires, is it absolutely necessary to match all 4 numbers from the old tire, or is it ok to buy any kind as long as all 4 match? what numbers are essential to match?2) How can you tell if tires are in good condition?3) How can you tell if its snow tires, summer performance tire, or all-purpose tires by looking at it?Thanks a lot everyone for helping me out.

Answer:

There should be a sticker on the driver's side door frame that indicates the tire size and inflation that your car should have. Take a lincoln cent and stick it head first between the treads on your tires. The penny should go in far enough that you can't see the top of Lincoln's head. If it doesn't, the tire is too worn. Snow tires have a very distinctive tread. If you have a four wheel drive vehicle, you're supposed to use four snow tires or none at all. I live in Maine and I've driven on all season tires for years. I can't even remember the last time I bought a snow tire. Regarding tire size - most states only allow tires a couple sizes bigger than what came on the vehicle originally. If you go beyond that, the vehicle won't pass a legal inspection.
P-R is P-Metric Radial 215 is the width of the tire in mm 55 is the ratio of height to width in % (aspect ratio) 17 is the diameter of the wheel in inches. The diameter cannot change. The width is dependent on the width of the wheel, and should not change. The aspect ratio controls the outside diameter of the wheel/tire and affects radial clearance of the tire and accuracy of the speedometer and also should not change. The 93V is the load/speed rating and may change. Buy a reputable brand of tire from a reputable dealer. I went with Michelins from Costco. Your tires are your contact with the world. Don't skimp on quality to save a few bucks, it is not worth it. Snow tires generally have a toothier tread pattern. Most tires are all purpose and more than suitable for all driving conditions.
The P is for Passenger car tire The 215 is the width of the tire tread in MM The 55 is the height of the tire wall and is expressed as a %age of the tread width. In this case 55% of the 215 120mm tread wall height. The R tells you it is a RADIAL ply tire. The 17 is the tire rim diameter in inches. The 93 is the load rating of the tire. The V is the speed rating of the tire. The tires on each axle must be the same for safe handling. Preferably, all four tires should match. Note that the speed and load rating of all of the tires is equal to the lowest rated tire. Just because you have a 200 mph rated tire, doesn't mean the others can also go 200 mph. Tires have a manufacture date molded into the tire wall near the bead. A four digit number with an oval around it in the format YYWW indicates that it was manufactured in 20yy, week number ww. So a number of 0632 means the tire was manufactured in 2006, week number 32 (about August). Avoid 3-digit manufacture date codes. These tires were manufactured BEFORE 2000 (very old tires even though they have never been mounted). Snow tires have a very deep tread and it wraps around to the side wall - very pronounced as opposed to regular tires. If the tires are new, and recently manufactured, the are most likely in good condition. Never buy used tires except in an emergency and only as a spare. Get a new tire for a spare. You can Google information on tire sizes and designations for more detailed info.

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