You could rotate them weekly, but driving on tires without proper inflation, unbalanced wheels, or an out-of-alignment vehicle, will shorten their useful life significantly.
Another factor affecting classic or older vehicles that are rarely driven are flat spots. In extreme cases, it will feel like you're driving over a washboard, and in those cases, those tires are ready to be recycled.
Like most consumables, tires have a shelf life and should have a date of manufacture stamped on the sidewall. However, that's when the tire was made, NOT when it should be replaced.
To my surprise, I learned that the National Highway Traffic Safety Administration (NHTSA) has no specific guidelines about tire aging, and instead defers to recommendations of tire manufacturers, which can range from 5 to 10 years.
To add to the confusion, car manufacturers also offer recommendations as to when to replace tires. And the U.S. Tire Manufacturers Association says there is no way to put a date on when a tire "expires" because of such factors as heat, storage, under or over inflation, and conditions of use.
So we have to make our own determinations.
HOW OLD ARE MY TIRES?
But does that mean they are safe and roadworthy?
A proper tire inspection can answer that question.
TIRE INSPECTION
In severe cases, doing the necessary repairs as well as replacing the tires may be the only course of action. Remember that the tires are the only part of your vehicle in direct contact with the road.
But even if there are no strange noises or vibrations, you still need to visually check your tires as part of a regular maintenance program.
Tread Depth: Forget the old Penny trick to check your tires. Instead, get a reliable tire tread depth gauge. They are available at most auto parts stores and usually cost under five dollars.
Proper Tire Pressure: This has to be the easiest way to maintain good gas mileage as well as extend the life of your tires. Get a decent tire pressure gauge.
Tread Wear: If you notice unusual tread wear around the edges or erratic wear patterns, also referred to as "cupping," have a professional determine the cause.
Cracked Tires: This is a byproduct of age, and visible cracks are a sign of dry rot. If this is the case, replace the tires!
HOW TO ROTATE YOUR TIRES
This is how I rotate the tires on my '76 Corvette. I do not throw the spare into the mix since it's a steel rim.
And I must add that having a QuickJack lift in addition to a Porter Cable impact wrench as part of my tool arsenal allows me to do this task in about 30 minutes, instead of an hour-plus when using a 4-way lug wrench, a jack, and jackstands.
According to the 1976 Chevrolet Service and Overhaul Manual Supplement, if your Corvette is equipped with radial tires, the Straight Rotation method is recommended.
This method switches tires from front-to-rear without crossing side to side. Furthermore, this rotation method is recommended for directional-tread tires.
What's crucial, I believe, is to get into the habit of doing this task consistently. Again, now that I have a portable lift at my disposal, I plan to rotate the tires every time I do an oil change or approximately every three thousand miles.
Another "maintenance" task I like to do while the wheels are off, is to clean them, especially the inside of the wheels. Brake dust looks horrible and builds up. And the longer you wait to remove it, the harder it becomes, and it can also stain the rims.
I spent time and money restoring a set of Kelsey-Hayes rims I found on CraigsList a few years ago, so keeping them as clean as possible makes good sense to me.
I also add a little bit of brake grease to the hub contact surface so the rims don't "weld" themselves to the rotors.
This project is finished by re-installing the wheels on the car and tightening the lug nuts correctly and then torquing them to 90 to 100 ft/lbs.
By correctly I mean that you want to tighten them in a five-point star pattern as shown in the photo below.
I like to keep my car as clean as possible, but now that I'm able to comfortably and safely crawl under it thanks to my QuickJack lift, I've come to realize that I have a LOT of suspension components to clean and detail.
The fun never ends!
Thank you for following my '76 Vette Blog!
Product Links... (#sponsored)
• Godeson Smart Color Coded Tire Tread Depth Gauge | Item #88702
• AstroAI Digital Tire Pressure Gauge
• Porter-Cable PCE211 7.5 Amp 1/2" Impact Wrench