Why did older cars have earth ground straps?

[afterburn 549]

If you have been on the planet for a while, you can remember when cars trucks and especially cop cars had two straps hanging down from the back touching the road.
Now I know fuel trks use specially made tires to ground to the road, and aircraft hook a ground up B4 fueling.
That is understandable.
But back in the day, lots of cars dragged straps.
Now do I need little steel taps for the shoes I wear....remember those?
Or more importantly, do I need ground straps?
Next month we can discuss why flat ground straps are used.

[JackDidley]

Ground straps were to stop static electricity. I need them for my truck. Winter time it shocks the crap out of me when I get out.

[VINMAN]

I still have a couple of those in an old box somewhere. My dad always had those on his cars when I was a kid. Supposed to be for static electricity, so you didn't get zapped when you touched the door handle.

.

[afterburn 549]

I guess cops were very tender? and, why do they not use them nowadays?

[911 Rod]

I could really use them on my Tundra as I get zapped all the time.
And maybe some curb feelers.

[Eric 951]

I remember in the late 70s neighbor across the street had a Monte Carlo with Cragars, big and littles, rake, air shocks, he had (2) hanging from the rear bumper more for aesthetics than anything(he also had the mini-chrome mud flaps)

[herr_oberst]

My cousin had a toy model of a Texaco gasoline tanker that had a little chain hanging down dragging the floor.

I became aware that the real fuel tankers had grounding straps, too. I was probably 5 and this was in the '60's.

I don't really remember them on cars though.

[speeder]

I dunno why people don’t feel the need anymore but if I had a Prius, I’d hang a set of those brass nuts in the rear.

[herr_oberst]

Originally Posted by speeder

I dunno why people don’t feel the need anymore but if I had a Prius, I’d hang a set of those brass nuts in the rear.

It'd be kind of funny if the brass nuts on the Prius lit up at night, maybe a blue glow.

[masraum]

Modern version on Amazon



Walmart


ebay

[Dixie]

Originally Posted by afterburn 549

Now I know fuel trks use specially made tires to ground to the road...

Huh, I just learned something new. Could you please explain how these work? I'd think, being rubber, they wouldn't provide any ground.

[GH85Carrera]

Many fires were started in dry areas from the sparks from the metal ground straps.

The only time I get shocked is getting out of my Velour seats in the El Camino. I learned long long ago too use the key I just pulled from the ignition to touch the door lock knob. The spark jumps from the key to the lock knob before I touch it. No more static and I feel no shock.

I have never felt a shock going to get in any vehicle.

[mjohnson]

Originally Posted by Dixie

Huh, I just learned something new. Could you please explain how these work? I'd think, being rubber, they wouldn't provide any ground.

"rubber" as you get it from a petro-plant or from a tree is an insulator. It's also kind of crap on its own for tires, so for that and other reasons we load it with carbon black (basically soot). Hence your black tires. It's better for its use and a little more electrically conductive. Now, load it with more conductive things and you can dissipate the static charge. No charge buildup = no electrical sparks.

In some workplaces that really, really care about static electricity - like with flammable liquids/gasses and propellants/explosives - you wear dissipative footwear and even make sure that your "rubber" tired furniture conducts enough electricity to the floor so as to prevent a charge buildup.

I've been places where you had to stand on a mat and get measured - if you weren't dissipative enough (i.e. "grounded") you couldn't even insert your access card to open the door.

And, now thinking about this, I finally understand why lots of vehicles like ambulances might have loose chains dangling and jingling. Thank you! Now I realize that I kind of knew but didn't really ponder it...

[mjohnson]

Originally Posted by GH85Carrera

Many fires were started in dry areas from the sparks from the metal ground straps.

The only time I get shocked is getting out of my Velour seats in the El Camino. I learned long long ago too use the key I just pulled from the ignition to touch the door lock knob. The spark jumps from the key to the lock knob before I touch it. No more static and I feel no shock.

I have never felt a shock going to get in any vehicle.

As a 1980s kid and young 1990s driver in the cold midwest and on crap tires I was told to "poke" at the doorframe with my elbow to make the shock at least go to a less painful spot.

I guess some of the earlier "super MPG efficient" tires were even worse for static - though IDK if that's still the case.

[cockerpunk]

drifters will drag chains behind their cars to make sparks.

[masraum]

Originally Posted by mjohnson

"rubber" as you get it from a petro-plant or from a tree is an insulator. It's also kind of crap on its own for tires, so for that and other reasons we load it with carbon black (basically soot). Hence your black tires. It's better for its use and a little more electrically conductive. Now, load it with more conductive things and you can dissipate the static charge. No charge buildup = no electrical sparks.

In some workplaces that really, really care about static electricity - like with flammable liquids/gasses and propellants/explosives - you wear dissipative footwear and even make sure that your "rubber" tired furniture conducts enough electricity to the floor so as to prevent a charge buildup.

I've been places where you had to stand on a mat and get measured - if you weren't dissipative enough (i.e. "grounded") you couldn't even insert your access card to open the door.

And, now thinking about this, I finally understand why lots of vehicles like ambulances might have loose chains dangling and jingling. Thank you! Now I realize that I kind of knew but didn't really ponder it...

In addition to dangerous situations (around inflammable explosive materials) working with sensitive electronics often also has a requirement for folks to be grounded (wrist straps, mats to stand on, etc...).

[WPOZZZ]

Originally Posted by herr_oberst

It'd be kind of funny if the brass nuts on the Prius lit up at night, maybe a blue glow.

So, blue balls. Perfect, so those cars don't multiply.

[afterburn 549]

Dixie-
I have no clue but could guess.

[masraum]

Originally Posted by mjohnson

"rubber" as you get it from a petro-plant or from a tree is an insulator. It's also kind of crap on its own for tires, so for that and other reasons we load it with carbon black (basically soot). Hence your black tires. It's better for its use and a little more electrically conductive. Now, load it with more conductive things and you can dissipate the static charge. No charge buildup = no electrical sparks.

In some workplaces that really, really care about static electricity - like with flammable liquids/gasses and propellants/explosives - you wear dissipative footwear and even make sure that your "rubber" tired furniture conducts enough electricity to the floor so as to prevent a charge buildup.

I've been places where you had to stand on a mat and get measured - if you weren't dissipative enough (i.e. "grounded") you couldn't even insert your access card to open the door.

And, now thinking about this, I finally understand why lots of vehicles like ambulances might have loose chains dangling and jingling. Thank you! Now I realize that I kind of knew but didn't really ponder it...

Originally Posted by afterburn 549

Dixie-
I have no clue but could guess.

mjohnson got you.

[Dixie]

Originally Posted by mjohnson

"...Thank you! Now I realize that I kind of knew but didn't really ponder it...

An honest thank you. I love knowing why.

I once watched YouTubes about tanks for a month. Why? Because I didn't realize how fascinating they are. Plus, you never know when the girl's dinner conversation will switch from clothes and makeup to WWII tanks.