Metal chains hanging from truck rear axle?

[NetWareHead]

I see this from time to time. Most of the time its an ambulance but sometimes a big dump truck as well. Hanging off of the rear axle are chains. Why are they there? There are not tire chains; I once passed a truck like this that had the rear axle chains but also a tire chain holder on the side when they were not mounted on the tires. I can't imagine the purpose. Towing? Any idea what these chains might be for?

 

[JulesMaximus]

http://www.onspot.com/

 

[BoberFett]

Now that is a clever-ass invention.

 

[Uhtrinity]

The ones hanging off the center can be used to discharge electricity to avoid electro static discharge.

 

[Zenmervolt]

The ones hanging off the center can be used to discharge electricity to avoid electro static discharge.

This.

In some cases they're also placed behind mudflaps to keep the flaps from blowing too much and becoming ineffective, but that's not as common anymore.

ZV

 

[ThatsABigOne]

I see the chains on school buses all the time. Never understood what the point was. Jules' link is interesting...

 

[exdeath]

Came to post electrical grounding but it's already been covered.

See the same thing with carts in labs and stuff.