My .02
re:**
I agree with you guys in the sense that a tow vehicle that is slow is really not unsafe as long as it can maintain a reasonable speed
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I tend to disagree with that statement. Before I explain why, I would just like to say I tow trailers on an almost daily basis (big and tiny for landscaping purposes), I have towed loads with trucks from S10's to tri-axle dumps, bumper pulls to goosenecks, and even moved tandems (granted I don't have a tandem certification but I only moved them within a lot where I worked in North Carolina). I have hauled demolition derby cars, tractors, broken down cars, broken trucks, and have helped others tow.
I am no expert and don't claim to be, but I do hope that I have some common sense. I believe there is a fine line between the "numbers" and reality. A rig may be rated to tow a load, but if the tow rig is equipped with dry rotted tires, poor brakes, worn out steering components, etc than the numbers don't mean jack.........and trust me, I see guys at the pulls do it all the time (even seen a few on the side of the road). I also know the "numbers" have a safety factor built into them, so going slightly overweight although legally illegal, isn't necessarilly a bad thing in and of itself.
I will say that towing a load that is too heavy for the "powertrain" (even if within the safe weight limit of the chassis) is asking for trouble. For a one time emergency tow, or short distance trip, etc there is some room for argument, but to tow a load consistently that causes the tow vehicle to not be able to get out of it's own way on flat ground is dangerous. I don't say you have to be able to manever as if you didn't have a load or that every tow rig needs a blown big block or big TD, but the tow rig should be able to manever, accelerate, and BRAKE on level ground without having to push it (powertrain matched to the load). As a driver, I realize that I am not the only person on the road and sometimes I have to deal with other A$$holes out there. There are times where you may have to pull out near a blind corner or busy intersection and need to be able to clear traffic. Granted other drivers are supposed to be in control of their vehicles but we all know that is not the case. Having a vehicle that can hardly maintain speed (or needs to be floored to maintain it), or takes 8 miles to get up to speed (not counting steep grades) is not safe regardless of whether it is rated for the weight or not as there is other traffic on the road to consider.
If the tow rig is not able to get up to speed in a reasonable amount of time it may be able to be remedied with a gearing/tire change or engine upgrades, but beyond that the other remedy is to lighten the load or find a different tow vehicle.
I know everyone wants to be able to tow their trail rig, trailer, gear, tools, supplies, etc. with their 3/4 ton rig with 35's, 3.08's, and 305 because they can't affort the proper tow rig and the rig they have will move the trailer and "may" be rated for the weight. I used to do it but after using the right tow rigs (thanks to my buddies and bro-in-law) I have come to realize what could have happened. Now I don't tow unless I have the proper equipment (either mine or borrowed). I used to think that just because it fit and I could pull it, it was OK, now I don't.....
The sad part is, like religion and politics, we can debate this issue till the cows come home, but that is one of the reasons there are numbers (guidelines) and since the numbers aren't foolproof, we have to use common sense too. Hopefully I haven't pissed too many of you off.