Fifth Wheel hitch location

jb4xx · 05-09-2016, 01:19 AM

I bought a used drw f350 with rails mounted in the bed. When we upgraded from bumper pull to 5th wheel, the seller gave us the reese 20k slider hitch. Have a lot of bouncing so installed air bags. When I was installing the bags and shocks, I noticed the front rail is inline with the rear axle. This places the hitch almost 8 inches behind the axle. I have only towed once with airbags set at 35psi and towed nice on smooth surface at speeds, but bounced when over concrete ir changing speed.
Do I need more psi in airbags? Do I need to move the rails forward to center the hitch over the rear axle?

5th wheel is xlr 380amp tri-axle.

Thanks for helping!

shorthorn · 05-09-2016, 04:22 AM

Is the truck a short or long bed? Just curious, I don't think in either the hitch should be so far back. On my Ram 3500 dually, the hitch is about 2" ahead of the axle.

fmc · 05-09-2016, 05:13 AM

The hitch should be in front of the axle.

davel1971 · 05-09-2016, 05:56 AM

usually within an inch or so of axle center. Not sure what year your truck is, but looking at instructions for a 2011 and up F350, the rails are a inch or tow forward of the axle center. I'm sure you will notice a big difference when you correct this. http://www.etrailer.com/instructions.aspx?pn=C16424-204

jb4xx · 05-09-2016, 06:54 AM

It is a long bed. I looked at Google results lead me to etrailer web site. From what I read, the pin should be 2 to 4 inches in front of the axle which means my rails are about 8-10 inches behind where they should be.

DaveSchwartz · 05-09-2016, 08:56 AM

Yup, get that corrected and you'll notice less front-end float - especially with the pin weight on that AMP.

When installing, they must not have used the custom brackets - maybe they cheaped-out and used generic angle brackets without knowing what they were doing. On mine, with the custom brackets, it would have been impossible to get the positioning wrong because they only mount to the frame rails one way and then the holes for the rails are automatically in the right places.

biznsa · 05-09-2016, 11:26 AM

Quote:

Originally Posted by jb4xx

I bought a used drw f350 with rails mounted in the bed. When we upgraded from bumper pull to 5th wheel, the seller gave us the reese 20k slider hitch. Have a lot of bouncing so installed air bags. When I was installing the bags and shocks, I noticed the front rail is inline with the rear axle. This places the hitch almost 8 inches behind the axle. I have only towed once with airbags set at 35psi and towed nice on smooth surface at speeds, but bounced when over concrete ir changing speed.
Do I need more psi in airbags? Do I need to move the rails forward to center the hitch over the rear axle?

5th wheel is xlr 380amp tri-axle.

Thanks for helping!

Before going to all the trouble moving the rails, I would contact Reese directly and ask for their input.

Harkerr · 05-09-2016, 11:34 AM

When I mounted mine instructions were to set pin 1 inch forward of axle centerline. I have had no problems.

Big bird · 05-09-2016, 11:37 AM

CaptnJohn · 05-09-2016, 11:46 AM

F250 pin sits 3" in front of axel. Seems difficult to mount it that far back

TGR · 05-09-2016, 02:39 PM

Several manufacturers, including Reese, have custom brackets to mount their rails to the F350 that don’t require any drilling in the frame. They use existing holes and simply bolt on. As DaveSchwartz said, they must not have used the custom brackets designed for your truck or simply installed them wrong.

The front rail’s mounting slots are ~57” forward from the rear of my truck’s bed, which leaves the pin an inch or two forward of the truck’s axel. As you surmised, your rails aren’t properly mounted.

My truck is a single rear wheel F350 long bed with Air Lift air bags. It was a little tricky mounting the rail brackets with the already air bags installed. Your air bags may present a problem with mounting the rail brackets. You might need to contact your air bag manufacturer to ensure compatibility.

Since the hitch given was a Reese, the rails are most likely Reese rails but not necessarily. As biznsa recommended, contact Reese, a local hitch installer or perhaps etrailer for advice.

It may be best to install custom brackets from a new rail kit and avoid further drilling in the frame as well as the delays trying to make do with the existing kit can cause.

dicky1243 · 05-09-2016, 03:26 PM

Quote:

Originally Posted by jb4xx

It is a long bed. I looked at Google results lead me to etrailer web site. From what I read, the pin should be 2 to 4 inches in front of the axle which means my rails are about 8-10 inches behind where they should be.

jb you are correct the pin should 4 in. in front of center of axle.

davel1971 · 05-09-2016, 06:40 PM

get the correct brackets to mount rails to frame and there is no way you will put it in wrong location.

gunpro · 05-09-2016, 09:46 PM

I have installed all my own 5th wheel hitches, one chev and two dodges and all directions told me " on center(the rear axle) or three " in front. As of time of writing I have had no problems with this configuration.

18CrewDually · 05-10-2016, 04:14 AM

On the Fords the universal rail mount hitches end up being 2 inches in front of the axle centerline. The rail bolts will capture the cross member underneath. If it's an inch to far back or to far forward the bolts will end up in the cross member making it impossible to get a nut on it.

Oaklevel · 05-10-2016, 05:37 AM

Quote:

Originally Posted by davel1971

get the correct brackets to mount rails to frame and there is no way you will put it in wrong location.

Great idea probably were not available when the original owner installed the rails. Wish they had them when my rails were installed. Try here this is not for your truck you will need to look for that, but here is some good info...........

http://www.hitchpro.net/application/...ons/n50054.pdf

Good Luck

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