Photos of mid-sized vehicles - Post Here

NMBruce

NMBruce

Adventurer
As a possible future ZR2 owner, this worries me. Chevy saying that it needed trailer brakes and that the trailer was over weight by 100lbs and that was the cause. Even if the trailer had been at other reported 4100 lbs and not the 2100 lbs, the truck is rated to row more than that. As far as I know, trailer brakes help with the stopping of rig, not how the frame can handle a load. I would like to know how Chevy thinks the trailer brakes would of made a difference and kept the frame from bending.
As for his speed, well only the driver can tell us what is what, but 40 or 50 mph on a dirt road, forest road can be done in a lot of places. What if he had been on the Alcan Highway, Or other Alaskan roads, paved or dirt where permafrost can cause large dips in the road. I have a home build M416 trailer with a wood box, fully loaded about 1500-1800lbs depending on the box that I have pulled over the Alcan twice, once with a JKUR and once with a GX470, doing under the speed limit and I have seen my trailer wheels come off the ground.

I would really like to know the really story, because if it happened once, then it could happen again. Now, if he was doing jumps or something like that, then a different story, does anyone know the road where this happened and how bad that road is?
 
L

Lownomore

Member
NMBruce said:
As a possible future ZR2 owner, this worries me. Chevy saying that it needed trailer brakes and that the trailer was over weight by 100lbs and that was the cause. Even if the trailer had been at other reported 4100 lbs and not the 2100 lbs, the truck is rated to row more than that. As far as I know, trailer brakes help with the stopping of rig, not how the frame can handle a load. I would like to know how Chevy thinks the trailer brakes would of made a difference and kept the frame from bending.
As for his speed, well only the driver can tell us what is what, but 40 or 50 mph on a dirt road, forest road can be done in a lot of places. What if he had been on the Alcan Highway, Or other Alaskan roads, paved or dirt where permafrost can cause large dips in the road. I have a home build M416 trailer with a wood box, fully loaded about 1500-1800lbs depending on the box that I have pulled over the Alcan twice, once with a JKUR and once with a GX470, doing under the speed limit and I have seen my trailer wheels come off the ground.

I would really like to know the really story, because if it happened once, then it could happen again. Now, if he was doing jumps or something like that, then a different story, does anyone know the road where this happened and how bad that road is?
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As an initial claim denial if you have exceeded the tow capacity specifications in any way they can deny warranty. The question is would that claim hold up in court, in the rest of the world probably, but here in the US with a good lawyer probably not.

The real issue here isn't the initial tongue weight but the tongue weight applied during an off-road situation. While sitting at a stop or moving down a smooth patch of road the tongue weight may have been only 400lbs but when you get moving at a decent clip across uneven terrain and start bouncing the tow vehicle and trailer that number is going to fluctuate drastically. Perhaps the mechanical engineer above could do the math for exact numbers but the physics of it is relatively simple. If you hit the right set of whoops with the wrong speed and timing the rear suspension is going to be rebounding on the truck forcing it up and if the trailer launches poorly off a whoop at the same time the tongue is going to become a huge lever pushing down on the very end of the truck frame multiplying the tongue weight dramatically. Having spent years towing heavy loads it's not hard to see how this could cause the frame to bend as it did at the crumple zone.

People are placing way to much focus on the tow capacity of the vehicle and weight of the trailer and not looking at the additional tongue weight that can be placed on a vehicle in an offroad situation.
 
DaveInDenver

DaveInDenver

Middle Income Semi-Redneck
Lownomore said:
If you hit the right set of whoops with the wrong speed and timing the rear suspension is going to be rebounding on the truck forcing it up and if the trailer launches poorly off a whoop at the same time the tongue is going to become a huge lever pushing down on the very end of the truck frame multiplying the tongue weight dramatically. Having spent years towing heavy loads it's not hard to see how this could cause the frame to bend as it did at the crumple zone.
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The tongue weight won't necessarily increase. It depends on the geometry, though. The weight of the trailer is still it's center of mass relative to Earth, the tongue and its axle. Even airborne the truck doesn't necessarily see the trailer weight through the tongue.

It might if it was 90 degrees straight up and the vector goes straight down. But just bouncing over whoops it's possible the tongue weight could decrease and go negative. Problem is it's all speculation and dynamic, so it's not a simple J684 analysis once you leave nice, flat pavement.

524016
 
L

Lownomore

Member
DaveInDenver said:
The tongue weight won't necessarily increase. It depends on the geometry, though. The weight of the trailer is still it's center of mass relative to Earth, the tongue and its axle. Even airborne the truck doesn't necessarily see the trailer weight through the tongue.

It might if it was 90 degrees straight up and the vector goes straight down. But just bouncing over whoops it's possible the tongue weight could decrease and go negative. Problem is it's all speculation and dynamic, so it's not a simple J684 analysis once you leave nice, flat pavement.
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Agreed that it all changes off-road and is speculation. My personal experience is that I spent a lot of time moving tractors on a single axle trailer with a half ton truck when I was younger and completely understand how the trailer can actually unload from the hitch at times. I also experienced more than once a situation where the expansion joints on the freeway would cause a rapid load and unload cycle on the hitch and that is nothing compared to some of the whoops on a trail.

I've spent a lot of time in the automotive industry (thankfully free from that now) and my main point is that a lot of the people that have the knee jerk reaction of "he was under tow capacity so it must be GM's fault" probably don't have a lot of understanding about the stresses we put on our vehicles by loading them up then doing what we do with them.

It's hard to imagine that in the cases where this has happened recently there aren't any videos in this time of everyone having a camera (cell phone) on them all the time. It's a video I would be very interested in seeing.
 
DaveInDenver

DaveInDenver

Middle Income Semi-Redneck
Lownomore said:
I've spent a lot of time in the automotive industry (thankfully free from that now) and my main point is that a lot of the people that have the knee jerk reaction of "he was under tow capacity so it must be GM's fault" probably don't have a lot of understanding about the stresses we put on our vehicles by loading them up then doing what we do with them.
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I mentioned this in another thread about this frame, maybe this one, I dunno. People look at the GVWR and towing capacity and think that means a truck will do that under all conditions and that's false.

It can achieve the ratings under the conditions assumed during design and testing. IOW ideal conditions. Perfect tarmac, 75°F, slight tail wind the truck can do whatever. Run it over wash board roads with dips and you better be derating if you don't want to ruin your truck.

Problem is, of course, GM (nor anyone) sure as hell ain't gonna tell you what it can do when you're off road so we're left guessing. Knowing that is education and intuition but also experience and unfortunately one poor fella helps the other 1,000 know better.
 
L

Lownomore

Member
Is it legit for me to post a picture of one of our shop trucks in this thread? I used it for the weekend and it's a cool build I just don't want to come off as trying to advertise for where I work.
 
6

6gun

Active member
Lownomore said:
Is it legit for me to post a picture of one of our shop trucks in this thread? I used it for the weekend and it's a cool build I just don't want to come off as trying to advertise for where I work.
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Personally I say post it up! A cool truck that works is even cooler to me.

Sent from my LG-H700 using Tapatalk
 
L

Lownomore

Member
I drove this to North West Overland Rally, slept in it for three nights and then spent a day up in the hills taking photos of it. The owners of the company I work for like us to know our product and have offered this or one of our other rigs as available for trips. I love my FJC but this thing is nice.

From a weight on a Colorado standpoint I will mention that previous to the current setup, which isn't exactly lightweight, it had a Four Wheel Camper flatbed model on it and definitely saw some time off pavement. The owner and I had been talking about the frame previously as it's a question that has come up about mid-size trucks well before the recent couple of frame bends so I intentionally found a spot to really put a bit of twist to it. We've inspected the frame quite a few times as it does haul a load and have yet to see any signs of stress.
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L

Lownomore

Member
TantoTrailers said:
Thats sweet, is that a dog cage in the rear?
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Norweld calls it a dog box and much like the hunting rigs you see here with the kennel built into the bed the Australians use them for dogs sometimes. We have found that it's a good place to store or hard mount a generator so it can be secure but have good ventilation.
 
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