Tire Reference

How to Read Tire Size: Every Number Explained

Your tire sidewall has a code like P225/65R17 98H. Each part means something specific. Get any one of them wrong when shopping and the tire might not fit, might not handle the load, or might be speed-rated lower than your car.

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🔍 Most Likely Causes & Factors

30%
#1 - Most Likely
Width (225) - Millimeters

The 225 in 225/65R17 means the tire is 225mm wide from sidewall to sidewall. Most passenger cars run 195-275mm.

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25%
#2 - Very Likely
Aspect Ratio (65) - Sidewall Height %

The 65 means sidewall height is 65% of tire width. Lower numbers (40, 45, 50) are sportier and harsher. Higher (70, 75) are softer and more SUV-like.

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20%
#3 - Common
Construction (R) - Radial

R = Radial. Almost every modern tire is radial. You may also see B (bias-belted, rare) or D (diagonal/bias, mostly trailers).

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15%
#4 - Also Check
Rim Diameter (17) - Inches

The 17 is the wheel diameter in inches that this tire fits. This must match your wheel exactly.

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10%
#5 - Possible
Load Index (98) and Speed Rating (H)

98 = load up to 1653 lbs per tire. H = max 130 mph. Never go below your car's original spec. Higher is fine.

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📋 Common Tire Codes Explained

Code PartMeaning
PPassenger car (US tire)
LTLight Truck (heavier-duty)
225Width in mm
65Aspect ratio (sidewall % of width)
RRadial construction
17Wheel diameter (inches)
98Load index (1653 lbs)
HSpeed rating (130 mph)
VSpeed rating (149 mph)
WSpeed rating (168 mph)
YSpeed rating (186 mph)
M+SMud + Snow rated
3PMSFSevere snow rated (3-peak mountain snowflake)

🛠️ How to Find and Verify Your Tire Size

  1. 1. Look at your door jamb sticker Driver side door, lower edge of the jamb. Shows OEM tire size, PSI, and load index. This is the gold standard.
  2. 2. Compare to current tire sidewall Read the size on each tire. Mismatched fronts and rears are sometimes OEM (rare) - more often a previous owner mistake.
  3. 3. Note the load and speed rating When buying new tires, never go below the original load index or speed rating. Higher is fine; lower compromises safety and warranty.
  4. 4. Plus-size carefully Going from a 17 to an 18 inch wheel? The overall tire diameter must stay within 3% of original. Use tire-size.com or similar calculator.
  5. 5. Verify with the manufacturer Honda, Toyota, Ford and GM all publish OEM tire specs online by VIN.

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💬 Common Questions

What does 225/65R17 mean?

225 is the tire width in millimeters. 65 is the aspect ratio (sidewall is 65% of width = 146mm tall). R is radial construction. 17 is the rim diameter in inches. So this tire is 225mm wide, with a 146mm sidewall, fitting a 17 inch wheel.

What does the load index on a tire mean?

Load index is a number (75-130 typical) that corresponds to the maximum weight the tire can carry, in pounds. A 98 load index = 1653 lbs per tire. Never go below your vehicle's OEM load index.

What is tire speed rating?

A letter (S to Y) indicating the max sustained speed the tire is engineered for. S = 112 mph. H = 130. V = 149. W = 168. Y = 186. Never go below OEM rating - your insurance and crash safety depend on it.

Can I put wider tires on my car?

Up to about 20mm wider (one size step) is usually fine. More than that and you risk rubbing the fender or strut, throwing off speedometer, or stressing wheel bearings. Verify with a tire-size calculator first.

What does M+S vs 3PMSF mean on a tire?

M+S (Mud + Snow) is a self-certified all-season rating - any tire can claim it. 3PMSF (3-Peak Mountain Snowflake) is a real winter rating earned through testing. Real winter tires have both.

Where do I find the OEM tire size for my car?

Driver door jamb sticker - lower edge of the driver door when open. Shows tire size, PSI, and load info. Owner's manual also lists it.

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