Dear Tire Guy | November 2020
Do you remember the Mythbusters? I do. I also remember explicitly the warnings saying "do not try this at home" and thusly trying some of those very things. I fried several nerve endings and lost my eyebrows more than once, but it taught me to check my facts and love life... even with the twitch and facial scars I got out of it. As you may already know, there are many myths about tires. Some of these are even believed and recirculated by ones within the tire community. (Not us. Scouts honor.) Allow me to break a couple of these down for you.
First: All tires that are the same size, are exactly the same size. Nope. They're pretty close though. Production tolerances, mold qualities, and business practices all vary from company to company. If you've changed from one set to another and examined it you will likely notice a profile change, even if it seems slight. Bridgestone's 225/35R19 is going to be just a little different than MIchelin's, and Toyo's, and Hoosier's, etc. Even within the same SKU one batch might be a little wider, a little narrower, a little taller, a little shorter. Sometimes this is done to enhance performance. Sometimes it is done to save rubber and enhance profit.
Second: Lower profile tires on larger diameter wheels improve overall handling. Well, not quite. A shorter sidewall will enhance the tires' response to your turning the wheel making it seem as though you have more grip, however, there's more to handling than the initial turn response. Everything after that, the rubber compounds in the tire, the inflation level, the tread pattern determine really how well you are going to be able to corner. And don't forget that bigger wheels equal more unsprung weight, meaning more tire wear and even more difficulty controlling the vehicle if things get bumpy.
Don't believe the lies! Sorry, "misconceptions." Your tires are one of the biggest safety and performance features on your vehicle, make sure you have the hard facts on them. Stay safe and healthy Porsche fam, and until next month, Drive On!
~The Tire Guy