Towing anchor points - improvement needed!

E9Wayne

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Hey folks, well the Asheville vintage was going pretty well for me (for the most part, another story another time about crankshaft position sensors!) and the E9 guys with me until the day afterwards. I was on my way to @Ohmess and Tom Baruch's place in Aiken SC afterwards and my alternator bearings started going out noticeably a few miles before the destination. No worries, Chris and Tom have multiple alternators between the two of them and we picked one out and installed, along with some other punch list items... I was super happy that night after all the work was done and I would be heading home the next day after a nice dinner in downtown Aiken.

200 miles into my drive home the alternator dies and there was no warning light (I'm super sensitive to this after my experience at Monterey in 2016 with a failed voltage regulator and dash light that was telling me I was draining the battery was ignored by yours truly).* Macha rescued me back then. But I was around Statesville NC this time on my own this time in the boonies so I pulled over and waited almost two hours for AAA. Tow truck guy loads the car efficiently and I didn't worry too much about how he secured my E9 to this tow hooks.

We drive 4 hours together (over some bad roads along the way) back to Aiken to Tom/Chris' garage and arrive around 10 pm. While the tow truck guy is raising the bed to angle the car for releasing from the chains, the rear tow hook breaks off completely and the car sways to the left and somehow gets away from the front left chain anchor bending the front bumper and rolling back on the bed of the truck finally grounding itself a few feet before tipping completely over into Tom's driveway. Picture attached shows how center resonator and bottom of chassis prevented a full rear dive off the truck and hitting the driveway!
IMG_2293.JPG


Clearly the old rear tow hook was partially at fault but also the tow truck driver who was probably in too much of a hurry to offload my car...and the next morning we noticed a crushed center resonator against the driveshaft and dislocated driver side front bumper. Ok, these will be straightforward fixes after American Classic Insurance gets involved...

But the bigger topic here is where to attach the three hook anchors on most tow trucks to our E9s. After the fact it seems, for the front, that the factory tow hooks at the front of the subframe are best because that's what they were designed for, but I just had some subframe cracks welded at the tow hook juncture and the tow hooks were now both nice and straight. So when the guy attached those front hooks to the lower control arms on the inner side, I was not as worried even though I just had new arms installed and a full front alignment. That was probably a mistake too.

But the rear tow hook under the wheel well is another matter. That piece is super flimsy and broke right off at the puny spot welds that were done 52 years ago. I will have that rear tow hook reinstalled but both welded and bolted in for greater strength when I get around to repairs -- at the advice of Tom Baruch.

If this is not the best way to secure our coupes when a tow truck is needed, what are the better solutions?

Thanks all!

* replacement alternator was fine but not the voltage regulator that came with it and a new voltage regulator installed the next day cured the problem. I guess I really do have some bad luck with voltage regulators.
 
wow ... so lucky the car didn't get launched completely ... bad enough to have the issues you did have coupled with the ones from the tow truck. i tend to like the 'over / around the tire' straps that they secured my 911 down with as it was so low it was hard to strap it down effectively.
 
I have a fair amount of experience operating and training operators in a past life.

On a flatbed tow truck the car should be brought onto the truck using “J” hooks on the front control arms or rear trailing arms.

Once on the bed the wheels become the tie down points using nylon webbing or straps that ratchet tight to prevent movement.

There are many drivers that neglect to use the straps and simply use a “J” hook on the trailing end of the car and stretch it tight using the winch. This is not safe in the case of an accident, especially if the mounting point fails.

The tire method will not fail…and if it fails on one wheel the other three should hold tight
 
When I saw Wayne's call come in about three hours after he left, I thought "yeah, that's about how long it would take to completely drain the battery." It looks like there was a break in continuity inside the voltage regulator because there was no path to ground for the dash light, and thus no warning light indicating that the battery was slowly discharging. When Wayne described his problem, I thought of our 2016 drive to Monterey when we were heaing north up PCH and then east on a detour due to fires in our path. The sun was setting and shining constantly onto us and into our cars. Wayne thought the sun was illuminating his warning light when in fact his voltage regulator had failed and his battery was discharging. He ground to a halt and had to be towed that time too.

20160815_175944.jpg


I missed the excitement with the tow truck drop off as I had gone home rather than awaiting Wayne's arrival. But in the morning the regulator was an easy fix.

Alas, Wayne's schedule was now a mess given the extra day associated with heading back to Aiken. (People with jobs apparently have a hard time extending their car trips by a day or two). So, he decided to grab a plane and leave his car in Aiken. Bluebell is resting peacefully in my garage underneath Annabelle, and next to my e28 535is tranny swap project:

20250521_141237.jpg
 
Damn, Wayne, you have bad luck. Perhaps it's time for an alternator with built in IC regulator, and keep the old one as a prop next to the relays. I keep a spare in my travel kit.
 
I have a fair amount of experience operating and training operators in a past life.

On a flatbed tow truck the car should be brought onto the truck using “J” hooks on the front control arms or rear trailing arms.

Once on the bed the wheels become the tie down points using nylon webbing or straps that ratchet tight to prevent movement.

There are many drivers that neglect to use the straps and simply use a “J” hook on the trailing end of the car and stretch it tight using the winch. This is not safe in the case of an accident, especially if the mounting point fails.

The tire method will not fail…and if it fails on one wheel the other three should hold tight
Thank you, this makes total sense and I will insist that the tow truck operator come with the webbing or straps in the future!
 
That rear “tow hook” is never to be used as a tow hook as it is way too weak and neither should the front “Tow hooks” be used as they are commonly cracked or missing.

Listen to boonies- he knows what is correct.

J hooks and then straps…

Could you imagine tying down a Batmobile by the rear tow hook? Nooooo….
 
That rear “tow hook” is never to be used as a tow hook as it is way too weak and neither should the front “Tow hooks” be used as they are commonly cracked or missing.

Listen to boonies- he knows what is correct.

J hooks and then straps…

Could you imagine tying down a Batmobile by the rear tow hook? Nooooo….
thank you, Doctor Lawrence!
 
Non destructive testing examples
 
When I saw Wayne's call come in about three hours after he left, I thought "yeah, that's about how long it would take to completely drain the battery." It looks like there was a break in continuity inside the voltage regulator because there was no path to ground for the dash light, and thus no warning light indicating that the battery was slowly discharging. When Wayne described his problem, I thought of our 2016 drive to Monterey when we were heaing north up PCH and then east on a detour due to fires in our path. The sun was setting and shining constantly onto us and into our cars. Wayne thought the sun was illuminating his warning light when in fact his voltage regulator had failed and his battery was discharging. He ground to a halt and had to be towed that time too.

View attachment 202645

I missed the excitement with the tow truck drop off as I had gone home rather than awaiting Wayne's arrival. But in the morning the regulator was an easy fix.

Alas, Wayne's schedule was now a mess given the extra day associated with heading back to Aiken. (People with jobs apparently have a hard time extending their car trips by a day or two). So, he decided to grab a plane and leave his car in Aiken. Bluebell is resting peacefully in my garage underneath Annabelle, and next to my e28 535is tranny swap project:

View attachment 202646
Thank you Chris for the sleepovers with Annabelle.
 
The wheel strap method as @boonies mentioned is the go-too solution here in NL.

BMW themselves used the eyelets welded behind the rear wheels as tie down points when transporting them, apearently on rail cars between the Karmann factory and the BMW plant. These are oriented straight down, thus they are capable to loaded in (roughly) that downward direction.
I think these can also be used if for some reason the wheel strap isn't doable.

I think the rear tow hook is designed to take only purely horizontal loads; that way all ~15 welds are stressed in unison.
When strapping an e9 down on the rear tow hook, it is being pulled downwards, thus bending, thus loading only 1 or 2 of the spotwelds that are at the bending line. They'll snap, and the hook bends further exposing the next 1 or 2 intact spotwelds. It continues snapping them until you have effectively ripped the tow hook off.

some details of the tie down eyelets on my E9:
Originally, these are welded in with strip welds in 2 directions, mostly loading the rear wheel tub when strapped down; quite an ideal setup.
20201102_231106.jpg
1747989040297.png


freshly rezinced and welded back in:
20201102_230621.jpg


left and right eye just visible here as the fuel tank and spare wheel well are chopped out of the car:

20201102_233043.jpg
 

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The wheel strap method as @boonies mentioned is the go-too solution here in NL.

BMW themselves used the eyelets welded behind the rear wheels as tie down points when transporting them, apearently on rail cars between the Karmann factory and the BMW plant. These are oriented straight down, thus they are capable to loaded in (roughly) that downward direction.
I think these can also be used if for some reason the wheel strap isn't doable.

I think the rear tow hook is designed to take only purely horizontal loads; that way all ~15 welds are stressed in unison.
When strapping an e9 down on the rear tow hook, it is being pulled downwards, thus bending, thus loading only 1 or 2 of the spotwelds that are at the bending line. They'll snap, and the hook bends further exposing the next 1 or 2 intact spotwelds. It continues snapping them until you have effectively ripped the tow hook off.

some details of the tie down eyelets on my E9:
Originally, these are welded in with strip welds in 2 directions, mostly loading the rear wheel tub when strapped down; quite an ideal setup.
View attachment 202748 View attachment 202749

freshly rezinced and welded back in:
View attachment 202752

left and right eye just visible here as the fuel tank and spare wheel well are chopped out of the car:

View attachment 202753
neat solution!
 
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