Hitch, how far back

[trimster]

My truck has the hitch mounted right over the axel. In large part 'cause that's the way it came to me. I'm going to get an air ride hitch off season and that would be fine time to relocate the pin position.

 

How far back can/should I go?

[skp51443]

On my 4700 IH I moved mine as far back as I could, right to the rear edge of the bed and I'd have gone further if I could have.

 

Going to the rear helps both backing (more responsive to steering input) and tracking when towing (staying in lane) so it is well worth doing.

 

I don't recall the exact distance I went but I sure do remember how nice it was getting into our very tight winter spot right after the move. With the over the axle mounting I usually had to make about three cuts to get from the road to the gate and I had to be at the right angle across the road when I started. After the change I hit my usual angle to back in and almost hit the wall on the inside of the turn! The trailer had swung about six feet further to the inside than it had before the mod. The next summer on some tight northern back roads we liked I noticed I didn't need to steer the truck out of the center of the lane to keep the trailer from dragging the guard rail or crossing the center lines.

 

Weight transfer was minimal, 14 foot wheelbase and around a two foot move of about 2500 pounds of pin weight didn't amount to much although you could see a bit more clearance on the MorRyde front suspension when hitched.

[T.Gamo]

5' behind the rear axle and no real issues to speak of.

[chiefneon]

Howdy!

 

I'm on my second MDT first was a Chevorlet C5500 and now 4400 International. On both of them I have the Trailer Saver air hitch as far the the rear as possible. Never had a problem with either MDT and they came setup like yours before I moved them both. I like the way they track and back with the hitch far to the rear of the truck. It also gave me room to load a large scooter I carried on the back of the C5500. No need for that now we have a Toy Hauler.

 

"Happy Trails"

Chiefneon

[T.Gamo]

Have you seen the similar discussion in the HDT section? Many pics posted their.

[trimster]

I looked in the HDT section some time back. I figured there was enough difference between the two to warrant some input specific to the MDT.

And thanks all. I will be moving mine back soon.

[rpsinc]

trimsters,

 

Please add comments after you have used your IH with new location for hitch. I have a 2001 4700 with a Trailsaver in the stock (as installed by Stalick) location. I have been towing a DRV SS, only 11,700# dry + but will be moving up to a heavier Kounrty Aire 38' after remodeling is done. Curious to know what if does to overall handling and stability. Stan seems to have given us some feedback from his practical experience.

Anyone else done this on IH 4700?

 

Thanks all

[skp51443]

Stalick ordered his trucks with a hitch saddle (looked like a 1/2" forged [ shape) that sits across the frame rails, he had the bed built to just touch it when it was installed. He originally sold Holland hitches (big commercial hitch) that just bolted through the bed to the saddle. He offered other hitches later but they mounted pretty much the same way.

 

If you move the hitch to the rear very far it will no longer be completely over the saddle and since the bed floor isn't really load bearing by design you may want to put in a frame mounted support for the rear edge of the hitch. I originally didn't do that on mine but intended to add a support rail later, however since I didn't see much bed floor sagging I didn't bother to get one added.

 

I'd not go that route if your pin weight is very heavy, a sag will be a lot more grief than adding a support before it happens.

[house]

I would like to point out that depending on how heavy your tongue is you may not want to move it back at all. My FL50 came with a trailer saver hitch, and because of the bed design the hitch was 6 inches behind the axle, when my trailer was fully loaded it did not quite steer right. Later I installed a standard GN Ball further forward and the truck steered much better at highway speeds with heavy loads

[SKP]

I know this subject has been covered many times, but I still don't understand how the RV community (whose real world on the road experience is neither trivial, nor should be overlooked) has gravitated toward choosing severe aft of axle hitch points, while the tow vehicle manufacturers (whose adherence to FMVSS standards, avoidance of liability, and reliance on professional engineering acumen are all neither trivial, nor should they be overlooked) still recommend hitch points ahead of the axle, or at the very minimum, no further aft than axle centerline.

 

I can't understand how user experience can be in conflict with factory engineering from a variety of manufacturers, not just one.

 

While it is debatable whether my F550 cab chassis should be considered an MDT, Ford made it very clear in the Incomplete Vehicle Manual that a fifth wheel hitch point should be ahead of, and not behind, the rear axle. And this is on a 22' chassis with a 176" wheelbase, which is almost 15 feet. I would worry about being found liable under the "contributory negligence" theory, should a lawsuit arise out of a collision involving me, a trailer, and fifth wheel hitch point several feet behind where the manufacture told me to put it.

 

I'm not saying that anyone is wrong for doing so. I'm just having trouble understanding how there can be such a dichotomy between well meaning experienced users and well meaning experienced engineers on this particular subject of hitch point.

[Dollytrolley]

I know this subject has been covered many times, but I still don't understand how the RV community (whose real world on the road experience is neither trivial, nor should be overlooked) has gravitated toward choosing severe aft of axle hitch points, while the tow vehicle manufacturers (whose adherence to FMVSS standards, avoidance of liability, and reliance on professional engineering acumen are all neither trivial, nor should they be overlooked) still recommend hitch points ahead of the axle, or at the very minimum, no further aft than axle centerline.

 

I can't understand how user experience can be in conflict with factory engineering from a variety of manufacturers, not just one.

 

While it is debatable whether my F550 cab chassis should be considered an MDT, Ford made it very clear in the Incomplete Vehicle Manual that a fifth wheel hitch point should be ahead of, and not behind, the rear axle. And this is on a 22' chassis with a 176" wheelbase, which is almost 15 feet. I would worry about being found liable under the "contributory negligence" theory, should a lawsuit arise out of a collision involving me, a trailer, and fifth wheel hitch point several feet behind where the manufacture told me to put it.

 

I'm not saying that anyone is wrong for doing so. I'm just having trouble understanding how there can be such a dichotomy between well meaning experienced users and well meaning experienced engineers on this particular subject of hitch point.

Many times fifth wheel hitches hover at or near the "average" center of the rear axle(s) but not always......exceptions abound and not all are "negligence-prone-designed"..........

 

Many factory approved motor home units have heavy RV hitches installed more than 14 feet aft of the rear axle center and these units do not clog up the courts with "contributory Negligence" centered actions.......

 

Your correct that a lot of design considerations can play into various hitch locations but not one hitch location is sacred........

 

One thing often overlooked in center of axle hitch location is the very poor lack of trailer tracking relative to the tow tractor.......so having your trailer run over the folks on the sidewalk as you round a corner will likely get you into a "contributory-neg" action as well......

 

Life is.......sometimes not simple choices and factory engineers are looking out for #1.......(whoever #1 might be).

 

Drive on.........( be careful.........)

[Darryl&Rita]

Most of the trucks being discussed here are considerably larger than your 550, both truck size and axle capacity.

[skp51443]

SKP, First unless you are driving commercially and trying to get your truck's tax classification correct put the LDT, MDT, HDT out of your mind completely. That is all that it is and has nothing to do with the truck as such other than being ranges of weight it can carry. However, since your 550 can carry XXX pounds (too lazy to look it up) it is without question or quibble an MDT, which of course is useless information for an RV hauler since it isn't taxed on the classification.

 

Now on something like a 250 to a 550 pickup I'd say go with the recommendations of the manufacturer, the 450 and 550 are really just beefed up suspensions under a pickup body and a similar (possibly with a lower power output than the lighter units in the series) power train. You raise some interesting points about the possible downsides to non-recommended hitch locations, don't know how that would play out.

 

On the other hand, if you have something like a small Pete, Freightliner or IH truck then you are in a completely different range of hardware even though the tax classification is the same. There is no real reason to limit your hitch placement on one of them as long as it will function properly (not hitting anything) and you don't go too far forward or back and upset the front axle weight. There are some nice advantages to rearward mounting and anyone not getting close to the length limits should consider it.

 

The impact on the truck from moving your hitch two or three feet when mounted on a 13,000 + pound truck with 7,000 + pounds on the front axle, 11,000 + on the rear axle and with a 15 + foot wheelbase is quite minor. Much more noticeable impact on the fiver with improved tracking and faster turning when backing being the most obvious and welcome changes.

 

With a big truck like a Volvo or full sized Freightliner the impact is even less in proportion to the truck's weight.

[Dollytrolley]

SKP, First unless you are driving commercially and trying to get your truck's tax classification correct put the LDT, MDT, HDT out of your mind completely. That is all that it is and has nothing to do with the truck as such other than being ranges of weight it can carry. However, since your 550 can carry XXX pounds (too lazy to look it up) it is without question or quibble an MDT, which of course is useless information for an RV hauler since it isn't taxed on the classification.

 

Now on something like a 250 to a 550 pickup I'd say go with the recommendations of the manufacturer, the 450 and 550 are really just beefed up suspensions under a pickup body and a similar (possibly with a lower power output than the lighter units in the series) power train. You raise some interesting points about the possible downsides to non-recommended hitch locations, don't know how that would play out.

 

On the other hand, if you have something like a small Pete, Freightliner or IH truck then you are in a completely different range of hardware even though the tax classification is the same. There is no real reason to limit your hitch placement on one of them as long as it will function properly (not hitting anything) and you don't go too far forward or back and upset the front axle weight. There are some nice advantages to rearward mounting and anyone not getting close to the length limits should consider it.

 

The impact on the truck from moving your hitch two or three feet when mounted on a 13,000 + pound truck with 7,000 + pounds on the front axle, 11,000 + on the rear axle and with a 15 + foot wheelbase is quite minor. Much more noticeable impact on the fiver with improved tracking and faster turning when backing being the most obvious and welcome changes.

 

With a big truck like a Volvo or full sized Freightliner the impact is even less in proportion to the truck's weight.

 

Stan brings up some very good point to consider.........

 

I never cease to be amazed how often the "normal-pick-5er-combo" is considered to be the "Gold-Standard" for RV trailers......rear-axle-center-hitches have some utility........IF......the RV tower IS WILLING to utilize commercial-driver tactics to deal with the very poor trailer track compared to the tractor track........

 

Many fifth wheel RV drivers clip the front corner of the pickup utilizing the sharp angles of turning a unit as they backup......commercial drivers keep a eagle eye watching the front swing of the tractor as well as the track of the trailer.

 

Very few RV fifth wheel owners understand the extreme stress's induced into the trailer suspension when executing a wheel-point-pivot-turn at 90 degrees or more while sliding the tires sideways...... Most RV trailer suspensions are ill-designed to sustain the stress of wheel-point-pivot-turns and as the results we often see over-stress-failures on RV units........

 

Commercial training teaches that turns should be as proportional as space permits and that wheel-point-pivot-turns are to be limited as much as possible.........most commercial trailers are designed to handle the stress's of wheel-point-pivot-turns but still the practice is not encouraged.

 

Many RV sales folks tend to use the wheel-point-pivot-turns as a big selling point and often they assume the trailer will handle the action without any adverse consequences.............often the consequences occur after the short warrantee expires............

 

Properly engineered aft-of-axle hitches often allow the driver to obtain better tractor-to-trailer tracking without over-stressing- loads or sharp turns......

 

Drive on...........(be aware of your........tracking)