duster75

Building a self engineered 5th wheel plate for my 98 2500 and What has got me is the hole in bed floor. Would like to have a measurement from tailgate end of box to center of hole for ball.I see where the plate itself should bolt up. The thing that has got me is tank location seems like it will interfere with plate. Thanks, Nate

nkennedy

Fifth wheel hitches can be had used for cheap any day on Craigslist. Why would you build one?

Jaxom

Almost sounds like he's talking about a G/N!?!?!?

duster75

I guess I should check it out...... and yes.... not in proper terms I'm talking about a gooseneck with a 2 5/16" ball in center not a 5th wheel plate like you would find on the back of a semi tractor.Sorry for confusion... I work in steel fab. on a daily basis so mat. is cheap for me and design time is paid for by the man.CNC Plaz. torch, breakpress all at my disposal. I guess I need to find a truck with 1 and copy design but Ido not have 1 close at hand right now.Nate

Haulin_in_Dixie

Get two pieces of 2 inch angle iron about a foot long. Get your plate 3/4 or thicker so that it will go from 2 inchs wider than the frame on both sides. Drill the ball hole in the middle. You will see indentions in the frame for the angle iron placement which should bolt onthe outsied of the frame. Then the [plate bolts on top. If you don't understand what I am describing look at any non adjustable fifth wheel on a tractor. That is standard proceedure.

Haulin_in_Dixie

Oh yeah, the ball should be 4 inches ahead of the centerline of the axle in a perfect world. It is not a perfect world and you may have to fudge with the measure ment to work with your trailer and the clearance for turning at the front of the trailer. A measure ment of 52 inches from the back of the cab generall works. Most installations end up a little ahead of the axle centerline.

RollinCoalSmoke

I run my ball 2'' ahead of center of the rear axle with good results. As far as the measurement from one end or the other of the bed I never measured. I use a 1/8'' drill and drill a hole directly center of the rear axle and then move up 2''. The 18'' diameter 5/8'' thick plate covers over it. Don't know why I do it that way other than it was the way I was taught 35 years ago I guess.

Haulin_in_Dixie

The 52 inches is to assure clearance for the trailer to turn without hitting the back of the cab. On a big truck that is right at 5 1/2 feet but a goose neck setup is less foreword overhang so is shorter.

duster75

Thanks guy's that will do it.... I just talked to a friend tonight and the measurement I was looking for is 48" from rear on a 8' bed. And as far as clearance on tank issue.The plate has to be spaced off top of frame 2" to clear tank. thanks again, Nate

OldDodgeOwner

48 3/8" from the back end of the bed on a longbed will put the center of the ball 5" ahead of the axle.

Haulin_in_Dixie

Duster it would be wise to totally forget any measurement from the back of the bed. The cab to kingpin is critical as is the location near the centerline of the rear axle. On a '98 or '99 the plate lies directly on the frame and is about two inches below the floor of the bed.

wyododge

I have my bed off right now and I can take some measurements for you or shoot some pics if you would like. Just let me know what you would like measured and what pics you would like, if any. BTW it is the truck in my sig.

duster75

wyododge, that would be great.A pict. of your plate and how it bolts up would help in design of mine. We just got 6" of snow so I'll be plowing today $$$. Was hoping to have bed off last night but newborn changed plans.Hopefully will get truck in and thawed out so I can get bed off tonight. Haulin I will hold your 52" and see what needs to be done after box is off.I don't want trailer getting into back of cab for sure.I called my buddy back and he forgot to mention that his plate was mounted in bed, not under/directly to frame that must be the reason for the 2" spacer sorry for cunfusion. Nate

wyododge

Okay here you go.
From Left to right...
#1 Passenger side

#2 Driver Side

#3 I measured from here (end of screw driver) to center line of ball = 48 1/4" (Not to the center of the ball itself just where the center line of the ball meets the frame rail.

#4 I measured from here (bottom edge of spare tire assembly) to the center of the ball = 39"

#5 The 2x3 in this photo (to the right of the GN assembly) represents the location of the bed rail when the bed is reinstalled. there is a 1/2" gap between the right side of the GN frame and the left side of the 2x3.

Really the only question I am wondering is if the frame rails are the same length and if the spare tire assemblies are located in the same place on a 99 and a 02. Maybe someone will chime in and verify that. Good Luck!!! BTW my hitch is called a hide-a-ball.

Hope this helps, I will be outside all day, but I will have my phone on me if you need anything else 3074315136 give me a call. I hope to have the bed back on later this afternoon.

Haulin_in_Dixie

Very complicated, reinventing the wheel. All it takes is a flat plate layin gon the frame and an angle iron on each side bolted to both the frame and the plate. And to do this the bed does not come off, the plate slides between the frame and the bed.