Finding the Original Size: The best starting point is the sticker on your driver's side doorjamb. This will show the original tire size recommended by the manufacturer. This is crucial information because it ensures proper speedometer calibration, gearing, and avoids potential rubbing issues.
Acceptable Alternatives: You can generally go slightly larger or smaller than the original size, but staying within a certain percentage difference is recommended to avoid problems. A good rule of thumb is to stay within 3% of the original diameter. Larger tires will increase your speedometer error (making it read slower than actual speed) and slightly affect your gearing, possibly requiring recalibration or a tune-up to compensate. Smaller tires will cause the opposite effect.
Consider these factors:
* Rim size: The width and diameter of your wheel (rim) must be compatible with the tire size.
* Backspacing: The distance from the mounting surface of the wheel to its inner edge significantly affects clearance in your wheel wells. Incorrect backspacing can cause rubbing.
* Suspension Lift: If you have a suspension lift kit installed, you can fit significantly larger tires. Without a lift, larger tires are more likely to rub against the fenders, body, or suspension components.
* Rubbing: Test-fitting a tire is essential before committing to a purchase. Even with a small increase in size, rubbing can occur, especially during turning or with a load.
In short: I cannot give you a definitive answer without knowing your original tire size. Start by checking your door jamb sticker. Then, you can use online tire size calculators to explore options that stay within the recommended diameter change percentage and consider the impact on speedometer accuracy. Always prioritize safety and proper clearance. Consult with a tire professional for advice specific to your Blazer's configuration.
