Everytime I get out of my VW Jetta I get...

Dear Car Talk

Dear Car Talk | Nov 01, 1994

Dear Tom and Ray:

Everytime I get out of my 92 VW Jetta, I get zapped when I touch any part of the car's body! Is there anything I can do about this annoying problem? How long must I suffer?

TOM: Gee, Bernie, that's the same question I ask myself everytime I sit next to my brother.

RAY: We may have an answer for you, Bernie. Several months ago, a gentleman called our radio show with a similar problem. He had a '94 Honda Accord. He said he recently stopped at a toll booth, and when he handed the toll-taker his coins, the toll-taker jumped back in shock as he got zapped. "Oh," the toll-taker said, "another one of those new (expletive deleted) Accords!"

TOM: It turned out that the problem was the tires. All new Accords were coming with Michelin MXV4 "low rolling resistance" tires. Tire manufacturers are all trying to create low rolling resistance tires these days, because the less rolling friction the tires create, the better the car's gas mileage.

RAY: And one way of making tires with lower rolling resistance is to decrease the concentration of "carbon black" in the rubber, and replace it with "silica." Both substances help hold the rubber together and give structure to the tire. Silica just does it with less rolling resistance. No problem, right?

TOM: Well, after many of these tires were already on the road, people (like our friend the toll-taker) began to discover that carbon black had an additional property that silica didn't. It helped "ground" the car, and dissipate the static electricity that naturally builds up around a moving vehicle.

RAY: When we first called Michelin, they played Mickey-the-Dunce and said static shocks were purely a weather-related problem. But some months later, they admitted that the tires were, at least in part, responsible. Now they claim to have fixed the problem by adding more carbon black back to the compound. They're also replacing the early MXV4s with newer "fixed" MXV4s for customers who complain.

TOM: So the first thing you should do is check to see if you have Michelin MXV4s on your Jetta. Most of them came with new cars in 1994, but it's possible you bought them as replacement tires. But even if you don't have MXV4s, we've heard sporadic reports of static shock problems with other company's low rolling resistance tires. So if you have any kind of low rolling resistance tires on your car, you may want to check with the manufacturer and ask if they've had any problems with static electricity. And if they have, ask them if they'll give you some credit towards another set of their tires.

RAY: Now before you go stampeding your tire store complaining that you got three shocks last winter, remember that some static electricity buildup is inevitable. Static electricity is somewhat weather related, so you're bound to get some shocks in colder, dryer conditions. My brother, for instance, gets a shock everytime he gets into his 1963 Dodge Dart, even though it doesn't have low rolling resistance tires.

TOM: Yeah. My shock comes when it actually starts! 2517

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