posted by
someone claiming to be Edwin
on
Mon May 2 13:00 CST 2005 [ RELATED]
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I have a 1994 850 with 150,000 miles. Everytime I get out of the car, regardless of how long I am in there I get a shock when I touch the car. The problem seems to be getting worse. Can anyone tell me if they can help me out.
Thanks,
Edwin
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Edwin,
I bet you just got new tires, right? Are you in the northern or southern hemisphere? I bet winter is approaching, too. Am I right there also?
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posted by
someone claiming to be cn
on
Tue May 3 02:19 CST 2005 [ RELATED]
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to discharge the static (Your car key may have an electronic chip inside)
cn
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Edwin,
Your car sits on 4 rubber tires. If your getting a shock it is due to you "grounding" the car when touching it. There are solutions to this...
1. You can install a grounding strip behnd the rear tire -(which eliminates a
static build-up on the chassis.) or,
2. Wear rubber souled shoes, (which prevents grounding).
3. Avoid polyester suits.
Armie
--
'94 850 154000kms '86 760GLE 272000kms
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Arnie
I think it is the other way around, the static electricity is in the person not the car, the car is grounding you. More likely to happen with fabric seats and dry weather. Just a thought. That is if there are no shorts in the car.
Mitchell
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posted by
someone claiming to be 850 owner
on
Mon May 2 17:13 CST 2005 [ RELATED]
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You should figure it out SOON, and QUICKLY. I had the same problem with an '88 244 that I used to have. It would get worse and worse, I thought it was the cold weather??? But a few weeks later I was driving, and the wiring to my left rear tailight heated up and caught on fire..the bulb failure light came on but I didn't realize what had happened untli I smelled the burning plastic and saw smoke in the rear view mirror....the tailight and wiring harness was TOAST!!! This is a true story!!! So please find out where the problem is!!! Don't mean to scare you but it really happened to me.
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850 Owner,
Yours was one of the more comical posts I have seen in a while. While I don't doubt that you may have had an electrical problem with your car, I really doubt that it is related to the static discharge that was reported in the original post.
The electrical discharge (the "shock") arises from an electrical charge build-up. Such an electrical charge comes from the movement of two dissimilar materials (remember the glass rod and silk scarf experiment from high school physics class?) It is generally worse in the winter because of the lower moisture content in the air. Any moisture encourages the excess charge to leak off the car, lessening the shock to non-noticeable levels.
When tire manufacturers started making "low rolling resistance tires", they used less "carbon black", an age-old ingredient in tires. The carbon black is conductive and allowed the tires to let some of the charge leak off. The lower levels of carbon black in certain modern tires means that it is harder for the charge to leak off, resulting in more noticeable shocks.
A grounding strap (basically a piece of conductive rubber that hangs from your car and drags on the ground) can help, but they wear out quickly due to all the rubbing.
Switching to tires with more carbon black will also help.
Holding onto a key and discharging the excess charge between the key and the car also helps, as this "spreads" the flow of charge across the whole surface area of your finger touching the key. The charge still flows through you, but it is not painful since it is not all concentrated on a single point.
Hope this helps. I bet the original poster got new tires recently, and this is why the problem seems to be "getting worse". Summer will lessen the problem, because the air is wetter.
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posted by
someone claiming to be Edwin
on
Wed May 4 12:23 CST 2005 [ RELATED]
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Actually, I have had the same tires for the past 4 years. And ironically I sell tires where I work. I have spoken to reps from Michelin, Pirelli, Goodyear, and General and i have never heard of what you speak of.
Thanks,
Edwin
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I read once where there was an investigation of fires occurring at gas stations when people were putting gas in the cars. Apparently under the right circumstances a static spark can jump from the fuel nozzle to the filler neck and ignite the fuel vapors. One of the information items they were collecting for each incident was the type of tires on the vehicle. So the grounding characterists of the tires was one of the many variables involved in trying to determine the cause of these fires.
I don't mean to be an alarmist, the incident rate must be extremely low. Also, how many people turn off their cell phones at gas stations (about zero?) even though there are signs that say they can ignite a fire.
Another caution concerning static and fuel. Always put portable gas containers on the ground to fill them. Never fill them in the bed of the pick up or in the vehicle. At least that is what the safety precautions say.
--
'80 242 DL (20 years, 315k miles, retired); '95 855 GLT, (190k miles, suddenly retired by 16 yr old daughter); '99 V70 XC 105k miles and counting . . .
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posted by
someone claiming to be Mike
on
Wed May 4 00:29 CST 2005 [ RELATED]
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Interesting explaination and I too am interested in this subject because my wife is often shocked getting out of my cars, NOT just one car either btw. She's complained about this with (I think) every car I've owned yet I don't get shocked ever. Doesn't matter what tires I'm running either BUT yes, it's worse in winter when dry.
The tire idea is interesting BUT when seeking new tires, one usually has various reasons for selecting a tire (performance, handling, wear) and in all my years, I've never once seen where any tire manufacturer mentions percentage of "carbon black" or a tires ability to ground vs another.
I might try a grounding strap just to see if she complains less. Those shouldn't wear too fast really in that when the car is moving, they shouldn't be dragging on the ground, the moving air should keep them floating.
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