What this site does and does not tell you

This site reports geometry and arithmetic. It does not tell you whether a tire will fit your vehicle, or whether a fitment is safe or legal — clearance, load rating and road-legality depend on your specific vehicle and your jurisdiction.

That line is drawn deliberately, and it is worth explaining rather than burying.

Why arithmetic can answer some questions completely

"How much taller is this tire?" has one correct answer, derivable from two size codes and nothing else. So does "how far out will my speedometer be", "how many times does this tire turn in a mile", and "what axle ratio restores the engine speed I had". These are closed questions. Given the inputs, there is a number, and the number is either right or wrong.

Those are the questions this site answers, and it answers them carefully: one tested library, every page reading from it, no figure typed in twice.

Why it cannot answer the fitment question

"Will it fit?" is not a closed question. It depends on:

• Clearance, which varies with suspension travel, steering lock, wheel offset and backspacing, bump-stop height, whether the vehicle has been lifted, and what the inner fender liner is made of. Two identical trucks can differ because one has had a bumper changed.
• Load rating, which is a property of the specific tire and the specific vehicle. The vehicle's placard states a minimum; the tire's sidewall states what it can carry. Matching them is a question about two documents, not about geometry.
• Legality, which varies by country, state and province — tread depth, protrusion beyond the bodywork, overall height, and in some places whether the change was inspected at all.

None of those can be derived from a size code. A site that answered "yes, that fits" from two numbers would be guessing, and the guess would be confident-looking and sometimes wrong.

What to read instead

For clearance, the people to ask are owners of your exact platform who have already done it, and the answer usually comes with photographs of the inner fender.

For load rating, read the placard on your driver's door jamb, then read the sidewall of the tire you are considering. The load-index reference page explains how to compare them, which is arithmetic and is therefore something this site can help with.

For legality, the authority is whoever inspects vehicles where you live.

No verdict colours

The comparison drawing distinguishes its two tires by line treatment — one solid, one dashed — rather than by colour. There is no green tick and no red warning anywhere on this site, and that is a design decision rather than an oversight. A colour that means "good" would be a verdict, and verdicts are exactly what this site declines to issue.