I’ve been struggling to understand how water vapor affects tire pressure. So I launched an effort to do so. There were a number of questions: When is water a gas and when is it a liquid? Let’s start with the most important bit of information needed: How do we determine when water is a gas […]

The photo above is of a “greige roll” – a roll of tire cord, before it gets a coating of rubber by way of a machine called a calendar. The roll has tiny (and breakable) cross cords (called a weft) to hold the cords in proper position during the calendaring operation. Once calendared, the fabric […]

Let’s assume for the moment that there is an extra glob (How’s that for a technical term!) of rubber on the edge of the tread of a tire – and that the tire is mounted on a rim and inflated. If this glob has significant weight, it could cause a vibration in the vehicle. Let’s […]

Revised: December, 2024: At the bottom of this page, see the addition of Tyre Reviews Video (Jonathan Benson). /end Dec 2024 revision: I get a lot of questions about these kinds of tires. It’s pretty simple – REALLY! Directional Tires will have an arrow on the sidewall. If it doesn’t have an arrow, it’s non-directional! and it doesn’t […]

What you should get from this page: You will hear various recommendations about tire aging: How many years, how bad are the cracks, from date of production or date of install, etc. This page will give you MY recommendations and the justification behind them. They may not be perfect, but at least you will know where they […]

This article is about how you can’t calculate the size of a tire’s footprint. That is, the inflation pressure is not equal to the average foot pressure and you can’t calculate the size of the footprint even if you know the load and the inflation pressure. Included are a ton of examples gleaned from the […]

Rolling Resistance and Fuel Economy (Continued): Revised December 2025: I brought the page up to date and incorporated all the previous revisions. I don’t think I need to enumerate those any longer. /end Dec, 2025 revision If you don’t want to go through the entire page to get what is important: 1) There can be […]

Rolling Resistance and Fuel Economy: I once saw a study done by a vehicle manufacturer that said that tires consume 17% of the fuel consumption for a vehicle. Given the source, I assume that this is based on the EPA test used for determining the fuel consumption of a vehicle Further, this 17% means not […]

Work in Process If you came here to research what is causing your unusual and/or uneven tire wear, I suggest you start with this page on normal tire wear It will set the stage for what comes below. Unusual and Uneven Tire Wear: This page is mostly about identifying the cause of unusual tire wear – […]

If you came here to research what is causing your odd and/or uneven tire wear, I suggest you read this page first, then go here! Most tire wear occurs when cornering. Driving straight ahead is almost free. Put another way, there is a difference between “City Driving” and “Country Driving” and country driving results in […]

This article is about tire noise – what causes it, how tire manufacturers reduce it, and how the consumer can reduce it. Tire Noise and Noise Testing: I am going to talk about how tire manufacturers try to reduce the noise that tires generate. That may help you select a tire that doesn’t generate as […]

Speed Ratings: Before we start, I want to remind everyone that these web pages are generally about passenger car tires. When I discuss something that doesn’t apply to passenger car tires, hopefully it will be obvious. Here’s what you should get from this page: Historical background: Speed ratings are a 1960’s European invention in response […]

There are several tire standardizing organizations throughout the world, but I am going to concentrate on just three of them: The Tire and Rim Association (TRA) – The US organization (The cover of the 2005 Yearbook is at the top of this page) The European Tyre and Rim Technical Organization (ETRTO) – Europe (The cover […]

This article is about how tire dimensions work. – how they are specified by the tire standardizing organizations. If you haven’t read up on Tire Standardizing Organizations, I suggest you do so. It will help you understand this page better: Barry’s Tire Tech – Tire Standardizing Organizations Also, Tire Rack has done such a good […]

This article explains how tire load tables work. They define the relationship between inflation pressure and load carrying capacity. If you haven’t read up on Tire Standardizing Organizations, I suggest you do so. It will help you understand this page better: Barry’s Tire Tech – Tire Standardizing Organizations Below is a scan from the 2005 […]

One of the fundamentals about tires is sizing. There is a lot of confusion concerning tire sizing and this is going to explain it in general terms and basically how it works. As a general rule, tire sizing describes the physical dimensions of a tire – but that is only part of the story. It […]