# Question from Car Talk (but not ABOUT Car Talk) **URL:** \ **Category:** Factual Questions\ **Created:** [November 14, 2014, 4:03pm UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621 "2014-11-14T16:03:44Z")\ **Posts on this page:** 14\ **Page:** 2
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [November 15, 2014, 12:56am UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/21 "2014-11-15T00:56:27Z")
It must have been an old one since it doesn’t seem to be in their online puzzler archive. I wonder if the second part of the question could have something to do with the switch from above ground to underground tanks. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [November 15, 2014, 1:05am UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/22 "2014-11-15T01:05:25Z")
> [@beowulff](#): > > Because they are short. Believe it or not the SHAPE also comes into it. Turns out that that if there is a flat part (say a the flat roof of a large building) here, and the top of a pole there, (eg the top of a church spire) just next door, it hits the sharp one. So height isn’t the only reason… function choose\_target (height1, shape1, height2, shape2) ---
**Author:** ![busterpickle](https://avatars.discourse-cdn.com/v4/letter/b/258eb7/32.png) [@busterpickle](https://boards.straightdope.com/u/busterpickle)\ **Post date:** [November 15, 2014, 1:45am UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/23 "2014-11-15T01:45:19Z")
Back in the day, tires were made out of polyester. So, to be accurate, we would need to know the timeframe for the puzzler. Polyester would in fact build up more static electricity and the truck could/would build up a potential. I’m guessing, as the operator is bringing the hose from the tanker truck to the opening in the ground for the refilling, and probably some fumes out of the tank being in the air. And, if conditions were correct, a spark could occur and could ignite the fuel vapor assuming the vapor/air ratio was correct. So, a lot of variables to consider but it could occur. If having chains on the truck chassis alleviated this potential then it’s worth it due to the relative low cost. Also, another option is for traction. I forgot the name of it, but there is a “spinning device with chains” that is actuated and the pulley is pushed onto the sidewall of the tires causing the chains to spin underneath the tire to aid in traction. Some emergency vehicles have this. ---
**Author:** ![Spiderman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spiderman/32/230_2.png) [@Spiderman](https://boards.straightdope.com/u/Spiderman)\ **Post date:** [November 15, 2014, 2:14am UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/24 "2014-11-15T02:14:07Z")
> [@LSLGuy](#): > > I do sometimes see grounding chains dragging under / behind modern paramedic or fire vehicles. So I doubt the answer is that truck tires are conductive enough to eliminate the need for direct ground bonding. > [@electronbee](#): > > Also, another option is for traction. I forgot the name of it, but there is a “spinning device with chains” that is actuated and the pulley is pushed onto the sidewall of the tires causing the chains to spin underneath the tire to aid in traction. Some emergency vehicles have this. They are [automatic snow chains](http://www.onspot.com/indhisfr.htm). Once installed, they are activated in seconds with the push of a button. Even pulling an emergency vehicle out of service for 10 minutes to install chains before a storm could be catastrophic if that’s when a call comes in. They don’t need to be installed/removed before/after every storm, they are instantly available, & they really do work (I’ve used them on the ambulance). The older ambulance didn’t have them so we’d put chains on in advance of a storm. Gawd, that sucked driving that thing with the chains on before the snow fell &/or after the roads were cleared! ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [November 15, 2014, 6:07am UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/25 "2014-11-15T06:07:33Z")
They put automatic snow chains on the school buses around here too. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [November 15, 2014, 4:00pm UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/26 "2014-11-15T16:00:45Z")
> [@Spiderman](#): > > They are [automatic snow chains](http://www.onspot.com/indhisfr.htm). Once installed, they are activated in seconds with the push of a button. Even pulling an emergency vehicle out of service for 10 minutes to install chains before a storm could be catastrophic if that’s when a call comes in. They don’t need to be installed/removed before/after every storm, they are instantly available, & they really do work (I’ve used them on the ambulance). The older ambulance didn’t have them so we’d put chains on in advance of a storm. Gawd, that sucked driving that thing with the chains on before the snow fell &/or after the roads were cleared! The device I was talking about is not that. It’s a conventional grounding chain. As in a 2’ length of 3/4" galvanized hardware store chain hanging down near the rear differential. Which were universal on gasoline tankers in the 50s & 60s and are still occasionally seen on some emergency vehicles. Here in Miami, where nobody ever needs snow chains, automatic or otherwise. ---
**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\ **Post date:** [November 16, 2014, 2:26am UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/27 "2014-11-16T02:26:05Z")
> [@Morgenstern](#): > > I don’t remember seeing those straps, but I do remember those curb feelers that looked like whiskers sticking out of the side of your car. For those who are younger than Morgenstern and I, curb feelers, usually one at each corner of the car, would give the driver an audible SCRINCH when a car being parked got near a curb or another car. It’s cheaper than the other kind of “parking by ear.” > **[Curb feeler](https://en.wikipedia.org/wiki/Curb_feeler)** > > Curb feelers or curb finders are springs or wires installed on a vehicle that act as "whiskers" to alert drivers when they are at the right distance from the curb while parking. > The devices are fitted low on the body, close to the wheels. As the vehicle approaches the curb, the protruding feelers scrape against the curb, making a noise and alerting the driver in order to avoid damaging the wheels or hubcaps. The feelers are manufactured to be flexible and do not break easily. > Curb feelers are ... ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [November 16, 2014, 2:40am UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/28 "2014-11-16T02:40:31Z")
> [@AskNott](#): > > For those who are younger than Morgenstern and I, curb feelers, usually one at each corner of the car, would give the driver an audible SCRINCH when a car being parked got near a curb or another car. It’s cheaper than the other kind of “parking by ear.” i also saw a type where two in a V were at each corner, close to the wheels to protect the hubcaps and whitewalls. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [November 16, 2014, 3:24am UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/29 "2014-11-16T03:24:51Z")
> [@jtur88](#): > > That is extremely rare – so rare that when I saw your link, I new it was going to be in Alberta. It is the rarity that makes that video viral. For every car that is struck by lightning, there a thousand people standing out in the open who are. But the number of people standing outdoors at any given time (especially when there is a storm) is a tiny fraction of the number of cars sitting outside. Explain why so many people and so few cars are struck by lightning, given the numbers of them that are out in the rain… It’s common enough for me to have learned about it in elementary school. We were told the car was a safe place to go because the current would just pass along the exterior of the car. ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [November 17, 2014, 1:16am UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/30 "2014-11-17T01:16:00Z")
The puzzler was I believe from sometime between 1995 and 1998. ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [November 17, 2014, 2:19pm UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/31 "2014-11-17T14:19:33Z")
> [@CurtC](#): > > I believe I remember hearing it years ago. The answer to the second was that tires are conductive nowadays, IIRC. Wouldn’t this create a greater potential for the battery to drain away charge to the ground? A few times recharging a dead battery would suck…especially needing a passing car driver to _attempt_ to jump one (or two) massive 18 wheeler battery. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [November 17, 2014, 2:30pm UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/32 "2014-11-17T14:30:42Z")
> [@jtur88](#): > > That is extremely rare – so rare that when I saw your link, I new it was going to be in Alberta. It is the rarity that makes that video viral. For every car that is struck by lightning, there a thousand people standing out in the open who are. [Nonsense](http://www.snopes.com/science/tires.asp). Cars are struck by lightning constantly. It _doesn’t_ make the news because hardly anybody dies that way. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [November 17, 2014, 2:38pm UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/33 "2014-11-17T14:38:17Z")
> [@Enola\_Straight](#): > > Wouldn’t this create a greater potential for the battery to drain away charge to the ground? A few times recharging a dead battery would suck…especially needing a passing car driver to _attempt_ to jump one (or two) massive 18 wheeler battery. I can’t see why this would be a concern. All vehicles have negative earths these days, that is the negative pole of the battery is connected to the chassis. If the chassis has a connection to the ground, it would have no effect. (UK earth = USA ground) Using a car battery to start a heavy truck would not be possible. Cars are 12 volt and trucks 24 volt. This is aside from the considerable effort turning a truck engine takes. Additionally, modern trucks are very sophisticated and the on board computers do not take kindly to their being jump started. Most have a big sign in the cab or by the battery(s) saying not to. Of course a mechanic would know the correct procedure but it is not for the amateur. ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [November 17, 2014, 9:25pm UTC](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621/34 "2014-11-17T21:25:39Z")
> [@bob\_2](#): > > Using a car battery to start a heavy truck would not be possible. I’ve done it. Took a my car AND a jump-pack > **[Auto Repair, Service, Maintenance & Tires | Pep Boys](https://www.pepboys.com/)** > > Take care of your car in one place. Schedule your oil change and repair services today. Stores are open seven days a week. simultaneously, but it worked. [Previous page](https://boards.straightdope.com/t/question-from-car-talk-but-not-about-car-talk/704621.md?page=1)