Tire-Wheel
UTQG Explained: Treadwear, Traction and Temperature
Treadwear grades are assigned relative to each manufacturer's own reference, which makes cross-brand comparison far weaker than the numbers suggest.
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Tire-Wheel
Tire Speed Rating Explained: What Downgrading Costs
The speed rating certifies more than top speed. It is a proxy for construction and heat tolerance, which is why 'I drive slowly' is not the whole argument.
Tire-Wheel
Load Range vs Load Index vs Ply Rating: Three Systems
One tire can carry an E, a 121 and a 10-ply marking. They are three systems from three eras, and you cannot convert between them by reasoning.
Find Your Numbers
Keep Record of Car Specifications: Build a Spec File
Keep record of car specifications in one sourced file and stop re-looking up tire pressure, oil and torque figures every time you need them.
Tire-Wheel
Tire Load Index Explained: Why Lower Is Never Free
The load index is an index into a standard table, not a weight, and the scale is not linear. Here is what it rates and why going lower is never neutral.
Tire-Wheel
LT vs P Tires: What the Service Type Letter Changes
P, LT, ST and XL are not quality grades. They describe service type and rating conventions, and swapping between them changes how the tire is rated.
Tire-Wheel
Tire Size Numbers Meaning: P215/65R17 Explained
Three numbers in three different unit systems. Here is which is millimeters, which is a percentage, which is inches, and why that trips people up.
Tire-Wheel
How to Read a Tire Sidewall: Every Marking Decoded
A sidewall carries about six independent specifications plus manufacturing data. Here is what each marking governs, in the order you meet it.
Find Your Numbers
Door Jamb Sticker Missing? What to Do (Not Order One)
A reproduction label carries no authority. Recover the information first from the manual, the manufacturer and a dealer, then decide about a replacement.
Find Your Numbers
How to Tell What Trim Your Car Is (Badges Lie)
A badge is the weakest evidence on the car. Here is the evidence hierarchy for verifying trim, and why trim decides which part or spec applies to you.
Find Your Numbers
How to Check Recalls by VIN (Free, and What It Misses)
The official US recall check is free and takes a VIN. How to run it, why it misses service bulletins, and what a recall obliges the manufacturer to do.
Find Your Numbers
Why Two Websites Give Your Car Two Different Numbers
Five structural reasons published car specs disagree, and a ranking system for deciding which of the sources in front of you to believe.