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I found the towing report. Seems like maybe best to keep it below 7mph so there's no regen. Post #6 reports no adverse effects:
That's why dragging a car back to the pits at a racetrack probably won't cause any problems. OTOH, towing it on four wheels behind your RV @ highway speed would be disastrous.

In a nutshell, the PMSM will be generating some voltage, depending on the speed it's spinning. Every EV with an AC drive system (induction motors or PMSM motors) has an inverter that provides the 3 phase current for the motor. But, when things are run in reverse, like towing, it gets interesting. An induction motor requires a 3 phase signal for the rotor to make a rotating magnetic field. A PMSM will make a rotating magnetic field simply because it has magnets built into the rotor. That rotating magnetic field creates currents in the stator, which is electrically connected to the inverter. Every inverter has diodes that will rectify the 3 phase current into DC at some voltage. This is BEMF. If that voltage exceeds the battery voltage it will charge the battery. This uncontrolled charging of a lithium battery can be disastrous. That's the reason behind the manual's rules in Iceman's post# 34.

When I first purchased my 500e, I looked into this. I towed it using the cheepo tow dollies that support the front wheels and drag the rear wheels. As the manual says, that's safe.
 

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Apparently none of the 500's in the US have the threaded part for tow hooks (gas or electric).

Beats me why they added the molded hatch for the tow hook.

On one of the facebook 500e groups, a guy named Bond Shaun, added a tow bar so he could tow and do regen. I couldn't find the post where he gave the details, but I think there was some aftermarket structure he added to the car.
 

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Digging into those old pics, I found a couple more helpful ones:

The front structure is pretty symmetric. This is the drivers side, with the structure behind the "thingy" removed. I removed that piece because I needed access to the front swingarm. Unfortunately, I didn't take a pic of the part that connects the front vertical piece and the swingarm support. If you look close, you can see how the bumper structure connects to the front frame rail.

Tire Wheel Fuel tank Vehicle Automotive fuel system


In this pic, you can see how the swingarm support connects to that beam.
Automotive tire Motor vehicle Automotive exterior Rim Auto part
 

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Discussion Starter · #45 ·
Here are a couple relevant pics I found on the web. Unfortunately it doesn't look like the gassers are blessed with anything better... :(
View attachment 112531

View attachment 112532
Interesting. I was wondering what the gas versions had in that spot as well, since I believe you can get a tow eye from Mopar for the gas powered versions, but there's nothing on there for the 500E as far as I can tell. But I have three questions about all this:

1) @500e*clipse you said your Subaru tow eye won't engage with anything, so I wonder if my particular car just happens to have a hole behind that front tow hook cover that will mate up with the 16mm threads on that tow eye? If so, then that definitely speaks to the use of a tow eye as something not intended by Fiat.

2) If the tow eye is threaded into that piece of metal behind the bumper, which looks to only be around 2 mm thick or so, does that seem like enough to tow the car a short distance with (as in up onto a tow truck flatbed)? As you pointed out, these kinds of things don't tend to fail slowly or with much warning. I'd appreciate a real engineer's take on that.

3) If a tow eye isn't the solution to this, what attachment points should be used if the car does have to be towed a short distance or up onto the bed of a tow truck?
 

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Discussion Starter · #46 ·
Another fact to add to the growing body of knowledge about this: Using a small neodymium magnet on the end of a long screwdriver, I can tell that the material of the "thingy" that the threads screw into is indeed non-ferrous and seemingly non-metallic (based on the sound it makes when rapping on it with the screwdriver). I think the tube from the front of the bumper leading back to that hole is metallic, but is non-ferrous, so aluminum perhaps? I'm still toying with the idea of hooking up the tow eye to my truck and pulling the Fiat a few yards up my 5-degree inclined driveway. If I do, I'll film it and post it here.
 

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@ Dr_Sharp

Good questions -
1) I don't know; I'm looking into that today.
2) I'm not sure what you are asking. Are you are referring to the actual structural bumper, the metal part that goes horizontally across the front of the car ( in the upper left corner of pic # 43) ? I noticed that there is a hole approximately where its mounting structure connects. That may be a good possibility, but I wouldn't thread that hole; I'd try to put a sturdy, thick washer @ sturdy locking nut pair. I didn't unbolt the bumper, so I'm not sure exactly what's going on there. This part (the structural bumper) has been designed to take very high loads and NOT fail catastrophically (bend rather than break in half). It's probably one of the safer parts to attach a tow hook.

Regarding the vertical piece of metal behind the bumper between the frame rail and the structural bumper support: I think its' main purpose is to locate that bolt-on bottom frame rail (the one that I couldn't get a pic of, but is in the top pic @ post 44) and provide structure for mounting the heat exchangers. I wouldn't trust it for lifting the car or pulling the car by itself. However, I think that lower horizontal frame rail is strong enough to pull the car and the structure it bolts in to (the front of the swingarm link) is strong enough to take a tension load. In other words, if the "thingy" (I'm open to a better name - LOL) is sturdy enough to take the tension load from a tow cable, then that load will transfer to a structure that can handle the load. I absolutely DON'T think a tow eye bolted into a sturdy "thingy" could be used to lift the front of the car. That will bend and break stuff.

3) I think a tow eye is the best solution for pulling a car on to a tow truck or maybe pulling it a short distance to the pits at a race track. In my case, without a tow eye, the only accessible parts for a tow truck would be the front swingarms; everything else is covered. I'm just trying to figure out a safe place to connect the tow eye. I'm sorry if this is taking a while; that's the way I think about things...
 

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I'm still toying with the idea of hooking up the tow eye to my truck and pulling the Fiat a few yards up my 5-degree inclined driveway. If I do, I'll film it and post it here.
I very strongly advise against that, but IF you choose to do it, have someone in the Fiat to hit the brakes when the eye comes flying out, & make sure nobody is outside anywhere nearby to get hit by the flying parts &/or the towing strap/chain/cable/rope.
 

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Another fact to add to the growing body of knowledge about this: Using a small neodymium magnet on the end of a long screwdriver, I can tell that the material of the "thingy" that the threads screw into is indeed non-ferrous and seemingly non-metallic (based on the sound it makes when rapping on it with the screwdriver).
Good info; After poking around a little bit myself, here's what I found.
I was hoping that tube would at least be black anodized aluminum, but have to say it "felt" plastic. I know that's not very scientific; just my experience. I have a long hardened pick tool, so I scraped it, hoping to scratch off the anodizing, if that's what it is. It scratched easily, but didn't expose a silver color. I really suspect that it's plastic.

Additionally, I have those "magnets on an extension with a light" tools for retrieving stuff that falls into impossible places. It's smaller than 20mm, so I tried to see/feel anything else. I will definitely confirm the tube is not steel. However - at the end/bottom it looked like the frame color and did stick to the magnet. That was approximately 175mm from the front of the "thingy"
 

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Ok, just to verify strong the "thingy" :rolleyes: might be in a real Abarth, I looked up a replacement part on MoparParts.


First, it's called an "absorber" - I'm willing to call it the Mopar name... :)

Note that it interchanges with the 500e part. It's primary design purpose is to support the bottom of the bumper fascia under normal aerodynamic loads, but fail in compression.

It sure looks to me like there is an aftermarket opportunity for someone who could make something strong enough to support a real tow hook.
 

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In that case, I wonder about simply unbolting the absorber, slicing 1/4" off the tip, & bolting it back on with a 1/4" plate behind it, & a nut welded to the back.
I see nothing suggesting that the metal tube support is capable of being pulled on at all, other than there is a hole in the bumper. But we may also be missing a tension member that supports the metal part hanging down. It’s not part of the actual frame.
 

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I see nothing suggesting that the metal tube support is capable of being pulled on at all, other than there is a hole in the bumper. But we may also be missing a tension member that supports the metal part hanging down. It’s not part of the actual frame.
From the pics posted here so far you are completely right. Pic #44 top looks like there is absolutely nothing.

However, there is a front subframe on the Fiat 500, which is common on all modern unibody cars.
Going back to at least the '90's the front and rear subframes were separate but structural parts of a unibody chassis. I have two vehicles siitting in my shop that illustrate the unibody and ladder frame construction techniques. Both are from the mid '90's; a Mitsubishi Eclipse and a Toyota pickup. Wiki mentions and links to further info on the subframe concept.

Here's another shot I have from when I was doing the front suspension work. This is the passenger side of the car, looking down the steering link. The lower swingarm is near the bottom of the pic. The important thing to note here is the structure that goes around the swingarm.

On the right side of the pic, just below the swaybar connection is that bolted-on member that goes forward to the vertical front structure and the absorber. The endpoint is right behind the absorber, shown in post #43 top. The rear connection is shown in post #43 bottom. Sorry I didn't get a pic of the beam itself, but it is in the lower right corner of this pic. I had to remove it because I needed to remove the swingarm to replace the bushings.

Automotive tire Tire Alloy wheel Motor vehicle Tread


So the auto industry has gotten really good at making lightweight tubular structures by welding steel stampings into complex structures. This is partially shown in the pic below with the vertical part that connects to the main frame. This piece is a part of that subframe that goes back, fitting around the swingarm. The back part of the subframe bolts to the main frame slightly out of the pic's view on the mid-bottom left. For some reason they only included the vertical part and none of the main part of the front subframe in the pic shown in post #44 top.

Given that most of the braking, all of the acceleration forward-back and side steering loads are transmitted from the swingarm to the front subframe then finally into the main body, I'd venture the front subframe is strong enough to take the tension load required for short tows or lifting up a tilt-bed tow truck.
 

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In that case, I wonder about simply unbolting the absorber, slicing 1/4" off the tip, & bolting it back on with a 1/4" plate behind it, & a nut welded to the back.
I'm sorry, but I don't trust that part that much. From the pics shown so far and the ones on the Mopar website, I would venture the absorber is a plastic casting. For example look at the seam midway down the corrugated outside. Or maybe that's a compression failure feature. Also note the aluminum inserts for the bolt holes. If the part were any metal, they wouldn't have included those inserts.

I think some sort of steel part that replaces the absorber would be appropriate. It would be nice if the part would fit an off-the shelf tow hook like the Subaru one that's commonly available. My main challenge would be to make something that isn't ridiculously heavy, but that's a personal issue...:rolleyes:
 

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From the pics posted here so far you are completely right. Pic #44 top looks like there is absolutely nothing.

However, there is a front subframe on the Fiat 500, which is common on all modern unibody cars.
Going back to at least the '90's the front and rear subframes were separate but structural parts of a unibody chassis. This is mentioned near the end of the Wiki article.

Here's another shot I have from when I was doing the front suspension work. This is the passenger side of the car, looking down the steering link. The lower swingarm is near the bottom of the pic. The important thing to note here is the structure that goes around the swingarm.

On the right side of the pic, just below the swaybar connection is that bolted-on member that goes forward to the vertical front structure and the absorber. The endpoint is right behind the absorber, shown in post #43 top. The rear connection is shown in post #43 bottom. Sorry I didn't get a pic of the beam itself, but it is in the lower right corner of this pic. I had to remove it because I needed to remove the swingarm to replace the bushings.

View attachment 112567

So the auto industry has gotten really good at making lightweight tubular structures by welding steel stampings into complex structures. This is partially shown in the pic below with the vertical part that connects to the main frame. This piece is a part of that subframe that goes back, fitting around the swingarm. The back part of the subframe bolts to the main frame slightly out of the pic's view on the mid-bottom left. For some reason they only included the vertical part and none of the main part of the front subframe in the pic shown in post #44 top.

Given that most of the braking, all of the acceleration forward-back and side steering loads are transmitted from the swingarm to the front subframe then finally into the main body, I'd venture the front subframe is strong enough to take the tension load required for short tows or lifting up a tilt-bed tow truck.
ah I see it now, yes that’s sufficient to pull from
 

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I'm sorry, but I don't trust that part that much. From the pics shown so far and the ones on the Mopar website, I would venture the absorber is a plastic casting.
I'll try again: I wonder about simply unbolting the absorber, slicing 1/4" off the tip, & bolting it back on with a 1/4" plate sandwiched between the metal frame & the back of the plastic part, & a nut welded to the back.

Steel plate goes HERE (click to enlarge):
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I'll try again: I wonder about simply unbolting the absorber, slicing 1/4" off the tip, & bolting it back on with a 1/4" plate sandwiched between the metal frame & the back of the plastic part, & a nut welded to the back.

Steel plate goes HERE (click to enlarge):
View attachment 112568
Review my pictures and look at what I’m thinking is a flat painted metal tube at the bottom of it so you may need to drill that out with a holesaw to clearance for the nut
 
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