Covering the nuts and bolts of lug nuts

Dear Car Talk:

My problem is that my lug nuts have some kind of cover on them. And the covers are turning instead of the lug nuts themselves. How do I get the lug nuts off? – Sidney

RAY: Ah, the scourge of decorative nuts, Sidney. Lots of cars and trucks use chrome covers over their lug nuts. It gives the lug nuts a nice, shiny finish, because who among us wants dull-looking lug nuts?

But the downside is that they can corrode. Water and salt eventually get in between the chrome cover and the nut itself, and the nut swells up and you can’t get a socket on it. Or if you can get a socket on it, the chrome has separated from the nut, and the chrome moves but the nut doesn’t.

What we do is chisel off the chrome cover. The chrome is only about a millimeter thick, and once you remove it, what’s left is just the lug nut. You’ll then need a smaller socket. So, if the lug wrench that comes with your car is a 21-millimeter, you might need a 19-millimeter wrench now to remove the lug nuts.

Then you have a decision to make: Do you want to drive around with your lug nuts exposed? Or do you want to spend the money to replace them with new, chrome-covered lug nuts?

The downside of leaving them exposed is that eventually they’ll rust and corrode and be hard to remove. The other downside is that your lug wrench will no longer work, so you’ll have to buy a new one that fits your pared-down lug nuts and toss it in the trunk.

But if the car is 15 years old, and you’re not sure how long it’s going to last, leaving the lug nuts exposed might be a reasonable choice.

You might be unpleasantly surprised to see how much a new set of chromed lug nuts costs. If you get them from the dealer, you could easily spend between $5-$25 a nut depending on the car. And you need 20 of them.

You might find some at parts shops or online for about half that. But it’s still a lot to pay for something that really should last the life of the car – but doesn’t.

Good luck with these monumental decisions, Sidney.

Try this tire on for size

Dear Car Talk:

Can you tell me why tire sizes are designated as they are?

If I understand correctly, we have metric, English and a ratio. Like, a “235-75R15” tire is 235 millimeters wide, has a 15-inch hole in the middle for the wheel, and the sidewall height is 75 percent of the tire’s width.

Can you explain the rationale behind all these different measurement systems? It seems like a Brit, an American and a statistician walked into a bar … – John

RAY: Great question, John. And not an easy one to answer definitively.

The general answer is that the U.S. has stubbornly held onto its beloved feet and inches while the rest of the world has been trying to nudge us into meters and millimeters. And because that nudging has been only partly successful, we’ve ended up with a mish-mosh. That’s the technical term for it.

One key fact is that the U.S. has traditionally been a dominant world market for tires. We have a lot of people and have always had a lot of cars. So, the U.S. Department of Transportation got to set the original nomenclature for tires. That’s why, until the 1960s, the wheel size was in inches, the tread width was in inches and there was no sidewall height information (the percentage known as the “aspect ratio”). Back then all tires had the same aspect ratio, which was 90.

But then, technologically superior radial tires were invented in Europe, and the Europeans wanted to sell their tires in the huge U.S. market. And since the only legal requirement for selling tires in the U.S. was that the wheel size be stated in inches (because consumers didn’t care back then how wide a tire was), the Europeans just had to change that one number on their tires, and bingo! They had access to the world’s largest tire market at the time.

That’s when you started seeing radial tires with their widths listed in millimeters, because that’s mandated by the Treaty of Versailles. Or maybe it’s the Geneva Convention.

Of course, eventually, radial tires were manufactured here, too, and then U.S. tire makers wanted to sell U.S. tires in Europe, so they also adopted the millimeter rating for tread width.

Radial technology also allowed for wider tires and shorter sidewalls. That’s when you started seeing aspect ratios on tires. And I’m guessing that, at some point, the U.S. and the U.K. were such dominant car markets that the European manufacturers just said “OK, Uncle!” and started using inches for wheel size in Europe, too. Because if you check out tires sold in Europe, the vast majority have the same nomenclature that we use here.

So, it’s really a story of the mashup of globalization. And prepare yourself, John. In 50 years, you’ll probably see Chinese characters on the side of your Goodyear.

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