Join Date: Nov 2009
Thanked 4 Times in 4 Posts
An overloaded semi still has to fall within the bridge law even with a permit. That is why they have more axles and the longer length. Most trucks have 40k tandems with a GVWR of 52k but on a set of tandems you cannot load more than 34k legally by law but a split axle trailer can have 40k legally. Grossing 85k in a semi is normal. The heavy hauler trucks are the same as any other truck except for the occasional pusher axle. A normal semi without a pusher axle can pull 150k or more with the right trailer set up but has to get a permit since it is over 80k. Even though the trucks are designed to pull 80k they are still safe pulling 150k. These are usually escorted not because they can't stop and are unsafe which are safe but usually because they are too wide or too long or both.
How do the manufacturers come up with the GCVWR? To get the GCVWR you take the truck's and trailer's GVWR and add them to get the GCVWR. I think that the manufacturers come up with the GCVWR so that it can pull at X speed and maintain that speed up hills. Because if you look the higher the rear end the lower the GCVWR.
So is a 1 ton truck pulling a bumper trailer that is tandem axle with singles with one braking axle at the manufacturers GCVWR max safer than somebody pulling a gooseneck trailer with tandem duals with both axles braking at the max GCVWR that is set with the truck's and the trailer's GVWR combined? You have 2 axles, 4 hubs, 8 tires on the gooseneck than 1 axle, 2 hubs, and 2 tires braking on the bumper trailer. More tires contacting the ground, better stability, better braking because of this. Bumper pull trailers lift the front end off the ground unlike the goosenecks that transfer some weight to the front axle. Most gooseneck trailer's can stop a loaded truck without the help from the truck. Some have electric over hydraulic brakes but most are electric and when maintained properly will work when you want them.
Our 1 ton trucks pulls a tandem dual axle trailer with both axles braking. The GVWR of the truck is 13k and the trailer is 24k so it should have a GCVWR of 37k. As long as we don't weigh more than our GCVWR of 37k then we are safe. Now if we were grossing over that then we wouldn't be safe. As long as you don't overload any axle or set of tandem axles and under the GCVWR of the truck and trailer's GVWR combined then your safe. That is what they will look at if an accident occurs not the manufacturer's GCVWR. The manufacturer's GCVWR is not set by law and exceeding that with the proper trailer does not mean that you are unsafe.