Comments on: What Happens When You Add to a Frame?

By: jimnlin

jimnlin — Mon, 10 Mar 2008 02:54:40 +0000

a question was asked about what fed laws are broken if rear axle capacties are exceded for non commercial vehicle. Our 49 CFR motor vehicle regs on RAWR/FAWR/GVWR/ tire caps are same for commercial (FMCSA) or non commercial (NHTSA/FMVSS/DOT). See definitions in 49 CFR part 571.3 for GAWR/GVWR in any of the administration booklets or website that gives the full up to date regulation (not just a shortened version). Also part 567.7 gives some more input on legalities on vehicle alteration. See FAQ on NHTSA homepage under laws/regulations and FAQs for some input. There are 24 questions/answers and a few may give insite on vehicle alterations. NHTSA does have a contact email number.
As a former commercial hauler one thing I found in looking at regs is contact the state the vehicle is registered in for their input on how they interpet and enforce a particular NHTSA reg. Most states will be simular in enforcement as fed monies can be witheld for non compliance of those 49 CFR motor vehicle rags.
JIM

By: Denny

Denny — Fri, 22 Feb 2008 03:18:43 +0000

Brad,

I just logged on and found your blog post… thanks for addressing my questions. Did you hear anything back from GM? I cannot get answers from either Four Winds, Thor, or GM on this matter.

To Fred, I had RVSEF weigh my coach a couple weeks ago… about 85% of max on the front, and 100% on the rear… actually, I was 300 lbs over max on the drivers side due to poor weight distribution by Four Winds. Drivers side is more than 1500 lbs heavier even when empty except for fresh water. So much so that the coach leans 4″ when it is empty.

It would be interesting to know the front/rear axle scale weight as it leaves GM as an incomplete vehicle.

Denny

By: Fred Golden

Fred Golden — Tue, 05 Feb 2008 22:17:05 +0000

So what you are saying is you think that the manufacture only added weight to the rear axle when the motorhome box was added and the front axle weight stayed the same as it came out of the chassis plant. As the final manufacture, they are allowed to do that. Some manufactures even build RV’s with axles that are almost overloaded when they leave the factory.

As long as the front and rear axle weights are not exceeded, and both have a nearly equal percentage of their full capacity, then everything should be safe. But loading the rear axle to say 95%, while only loading the front axle with 60% of it’s weight rating might cause handling problems due to not enough weight on the steering axle. This can cause further problems if the owner wants to tow a trailer with a heavy hitch weight, and the ball is several feet behind the rear axle.

That is why taking your motorhome to a scale will inform you of what you can do to properly balance your RV. While some manufactures actually have 400 or more pounds difference between the two front tires, most do a much better job of balancing the RV.

Fred.

By: William A. Hart

William A. Hart — Tue, 05 Feb 2008 16:02:38 +0000

I have a problem with a Four Winds, Dutchmen Dorado 26 foot that doesn’t track at interstate speeds. It is a Ford V-10, short wheel base with a queen sized rear slide-out. The rear overhang, like many Class C or B and a half approaches 10 feet. The rig is equipped with Mitchlin 16 inch wheels. Compounding the problem is the large drinking water tank at the extreme rear of the passinger side of the coach.

The alignment was checked by a truck shop in the first 500 miles. I have installed Safe Steer on the front axels and a hvy sway bar on the rear springs to stiffen the rear sway. With a small reduction of air pressure in the front tires (79 vs 80lbs) the rig will mostly track at 60 MPH. I still have to correct the steering more often than is disirable. At 65mph I have to pay attention to the lane useage. Passing 18 wheelers or cement trucks are only a small bother. I have have a variety of rigs (Class Cs and an A) for seven years. This “downsized” rig is most troublesome! Any ideas? Any other Dorado drivers with similar problems??
WH