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Moving 5 wheel hitch backward


chevy3500

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Well I have decided to slide my hitch backward on my T2000 Kenworth, in order to haul an atv on the deck, I need an additional 18 inches for complete 90 degree turning. The truck is still tandem. After removing the wooden deck that was on it when I purchased it. it appears all that will need to be done is add about 24 inches of 1/2 in X 3 angle bolted to the side of frame (this is what's on it now) The 5th wheel (32000# trailsaver) is mounted to a sheet of 1/2 in plate which in turn is bolted to this angle. Is it really this simple??. I realize I will need to lengthen the airline.

Currently the pin is just slightly behind center of the two axles. after moving it as planned it will end up about 3 inches behind centerline of rear axle. Any issues here? Pull 40' toyhauler about 3500# pin weight?

Also how much clearance is usually required between the tires and deck, I know I have to account for when the air drains out of bags.

Thanks for the help

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52" behind the tandem center point and 24" behind the centerline of the rear. 5k pin weight, it 'lightened' the front tires from 10.5K to 9.5K. I used 4" sq tube with 3/8" walls. Used 1" x 3'" x 4" spacer blocks between the bottom flange and the tube.

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52" behind the tandem center point and 24" behind the centerline of the rear. 5k pin weight, it 'lightened' the front tires from 10.5K to 9.5K. I used 4" sq tube with 3/8" walls. Used 1" x 3'" x 4" spacer blocks between the bottom flange and the tube.

 

Whats the wheelbase on your truck Bill? How does it effect handling under severe braking or emergency manuvering? I have a 270" wheelbase and my pin is 60" behind the center of my single rear axle with a 6200lbs pin. I am 16,500# overall (8400 front axle 8100 rear axle) and calculated that I should have less than 1500# off my steer axle. I think I'll be ok on weight just have my concerns with handling.

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Extended frame 5 ft. Have a rollback deck with hitch mounted at back of deck. About 8 ft behind axle but would have to measure to be sure. Defiantly lightened the front axle. Have been moving stuff to front of deck to add wt to front wheels.

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If you stop at 3" behind the rear, you are gonna wish you went back further. From comments on here, I think 2-3' behind the rear axle (single or dual) seems to be a sweet spot that balances the load nicely and give you the ability to "wag the tail" to get into tight camping spots. Longer works fine, but you need to think more. At 2-3', you won't even notice a difference in ride/steering. (I moved mine and didn't)

 

As far as tire clearance, once you let the air all out and the axles are down on the stops, thats it. Technically you could build a deck that just clears a new tire at that point. Smart monkey says leave 2" for safety.

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I checked into running my jeep on ramps but with the hard top and spare tire I wasn't gaining any space so I just load it flat. If you load it backwards there is a gain in space

We dont have an option of leaving it flat. We need to gain 12-18" between the nose cap of our 5th wheel and the hood of our 4Runner. We need to push the rear end of our 4Runner up and to the front of the TV to gain the extra clearance. I have seen a few photos of different setups, but no one has any info on angles and cantilever design to give me. All sugestions will be appreciated.

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I built my bed a few years ago and just used redneck engineering. I stood back far enough to take a side picture of the truck and then stood the same distance from the car. I then cutout the car and placed it on the pic of the truck bed. Then when it looked good I built it. Used a yard stick in the truck pic to come up with a scale. It at least works to see what you want. My bed is only slightly angled and the front 12" of the car rides above the cab. This is a flatop, small sleeper.

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If you stop at 3" behind the rear, you are gonna wish you went back further. From comments on here, I think 2-3' behind the rear axle (single or dual) seems to be a sweet spot that balances the load nicely and give you the ability to "wag the tail" to get into tight camping spots. Longer works fine, but you need to think more. At 2-3', you won't even notice a difference in ride/steering. (I moved mine and didn't)

 

As far as tire clearance, once you let the air all out and the axles are down on the stops, thats it. Technically you could build a deck that just clears a new tire at that point. Smart monkey says leave 2" for safety.

Why will I wish I went back farther? handling wise or room on the deck wise? Wife is quite resistant on moving it back any farther than necessary ( doesn't like the looks)

Any hints on drilling the holes in the "heat treated frame? Haven't been able to locate a mag drill at any of the local rental shops.

Thanks for the replies so far :rolleyes:

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http://www.hhrvresource.com/truckbeds

 

In case you haven't found this page, you can see pictures of member truck beds, including some looooooong ones for carrying a vehicle the long way. The trailer will track with the truck better with the hitch further behind the drive axle. You won't have to swing as wide before you start making a turn, or going into the oncoming left turn lane or oncoming lane of travel (as much). In backing situations the trailer can be put into a spot without having to jockey or jackknife the truck and trailer so much to get the trailer to go where it needs to be.

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Mine had been singled and when I decided to build the deck for the smart I had the body builder extend the frame rails back to support the hitch plate. He made it strong enough to tow 40k.

 

My hitch is about 24" behind the rear axle centerline. Helped with weight distribution and an added benefit is it reacts like a flat tow when backing, works out well. Had no noticeable effect on handling on the road.

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Holy crap, 7' BEHIND the rear axle? What is your wheel base? Are you singled?

Singled and 237" WB if I recall? Just got it hooked together this afternoon, but had to finish the wiring and brake controller before a roadtest. Let you guys know tomorrow.......

 

20150613_153848_zpsfs8npfeo.jpg

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Thanks!

 

I measured today and WB is 238" hitch 7'1" behind the axle.

 

Weights with the tool boxes strapped on the bed approx where they will be mounted and 100 gals in the tanks was Front 9,500, Rear 7,280 Total 16,780.

 

Took the package out for a ride today and other than how weird it looks pivoting in the mirrors while cornering seems to drive fine. Probably even better with more on the deck. There was a little bit of porpoising on the rough sections of road like my old travel trailer towed. Might order up some new shocks this week to combat that.

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Thanks!

 

I measured today and WB is 238" hitch 7'1" behind the axle.

 

Weights with the tool boxes strapped on the bed approx where they will be mounted and 100 gals in the tanks was Front 9,500, Rear 7,280 Total 16,780.

 

Took the package out for a ride today and other than how weird it looks pivoting in the mirrors while cornering seems to drive fine. Probably even better with more on the deck. There was a little bit of porpoising on the rough sections of road like my old travel trailer towed. Might order up some new shocks this week to combat that.

 

 

 

Tony,

How bad was the porpoising? Was the rig level, or slightly nose down? At what speed did it manifest? Did you try any emergency braking?

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Why will I wish I went back farther? handling wise or room on the deck wise? Wife is quite resistant on moving it back any farther than necessary ( doesn't like the looks)

Any hints on drilling the holes in the "heat treated frame? Haven't been able to locate a mag drill at any of the local rental shops.

Thanks for the replies so far :rolleyes:

Handling. When I bought my rig, it still used the OEM hitch plate. It was a total pain trying to move the trailer "a bit to the left" in a campsite, cause you had to move the whole rear axle of the truck sideways to move the front of the trailer (ie pull way forward, back up again.) Then I built and installed an air hitch at the rear tail. Now it backs like a bumper pull--cramp the wheels and swing the tail to move the front of the trailer. A bit hard to describe, but it really helps--lets you "wiggle" the trailer better. I can get my 40' trailer into places a LDT with a 30' would have trouble with, just cause of the hitch position. Tracking too...the trailer doesn't cut the corner quite as much, but not as dramatic as the above. Of course, you get more deck room too!

 

One other advantage--its a LOT easier to check the latching/hitch when its near the back. I found it looked "funny" only at first, now it looks right. All of these advantages may not be as important as keeping the DW happy though! :(:rolleyes: I learned long ago that when she puts her foot down...smart monkey listens! Quick story: One day many many years ago young wife comes home from getting groceries in town and says "I saw a nice camper for sale across from the Caseys..." "Ahuh" "DEAR--I saw a nice camper for sale..." "Sure, but you know we can't afford to..." "DEAR--I think we should at least look at it!" (AH. Smart Monkey light dawns...this is IMPORTANT.) "Yes dear." That was a great little (19') camper until we outgrew it! :P

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I learned long ago that when she puts her foot down...smart monkey listens! Quick story: One day many many years ago young wife comes home from getting groceries in town and says "I saw a nice camper for sale across from the Caseys..." "Ahuh" "DEAR--I saw a nice camper for sale..." "Sure, but you know we can't afford to..." "DEAR--I think we should at least look at it!" (AH. Smart Monkey light dawns...this is IMPORTANT.) "Yes dear." That was a great little (19') camper until we outgrew it! :P

 

LOL 2 months short of 35 years, and I learned that lesson quite a while ago too. Life is easier now!

So I got the new angle put on ended up using 1/2 X 3 X 4 and matched up exactly with what was on there. Was very surprised to find the original angle (same dimensions) is aluminum!! It appears to be original? Ended up putting the hitch right to the end of the frame, didn't measure exactly how far behind rear axle it is to pin but probably 12 inches anyway. When (if) I single it, it will be more.

Thanks

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I learned long ago that when she puts her foot down...smart monkey listens! Quick story: One day many many years ago young wife comes home from getting groceries in town and says "I saw a nice camper for sale across from the Caseys..." "Ahuh" "DEAR--I saw a nice camper for sale..." "Sure, but you know we can't afford to..." "DEAR--I think we should at least look at it!" (AH. Smart Monkey light dawns...this is IMPORTANT.) "Yes dear." That was a great little (19') camper until we outgrew it! :P

 

LOL 2 months short of 35 years, and I learned that lesson quite a while ago too. Life is easier now!

So I got the new angle put on ended up using 1/2 X 3 X 4 and matched up exactly with what was on there. Was very surprised to find the original angle (same dimensions) is aluminum!! It appears to be original? Ended up putting the hitch right to the end of the frame, didn't measure exactly how far behind rear axle it is to pin but probably 12 inches anyway. When (if) I single it, it will be more.

Thanks

You won't regret that move to the rear...

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Tony,

How bad was the porpoising? Was the rig level, or slightly nose down? At what speed did it manifest? Did you try any emergency braking?

The porpoising was more than I liked, but the section of road we were on was not smooth. I suspect on I-5 and the like it would be smoother than the pickup. The air pin is on the way and will likely damp some of that too. Nothing in the toyhauler's garage makes the nose a little heavy right now.

 

The truck is tail high till we hook up and then level when hitched. The trailer appears to be level, but measurements show it to be a tad low...again, the loaded garage will change that slightly.

 

I have been looking at shocks since I know this will help and the rears look to be original, but have been unable to figure out exactly what I need. The OE numbers on the shocks don't cross. I don't know if I have new or old air leaf for the rear and setback or not in the front...... Might have to pull one of each and measure to be sure.

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