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Open Roads Forum  >  Truck Campers

 > Frame Stiffing to reduce Porpoising?

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Grit dog

Black Diamond, WA

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Posted: 01/22/23 10:41am Link  |  Quote  |  Print  |  Notify Moderator

eHoefler wrote:

Your center of gravity needs to be forward of the rear axle to place weight on the steer axle. Like a poster said earlier, move the camper as far forward in the bed as possible. When you add water, your porpoising goes away, that is a dead give away that you don't have enough weight on the front axle.

Agreed in general, but with a crew cab and 1000lb engine up front he’s not in any way too light in front. And he did not say water/no water makes a difference. And there very little chance it does.
Now with greater weight aft of the rear axle even front weight ok, that is a fat kid on one side of the teeter totter.
But the primary issue is he feels it has excessive frame flex. Not going to even remotely begin to cure that by shuffling a few hundred lbs around and not going on a big diet in the rear end.
And the right roads will porpoise a lightly loaded truck.


2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

Grit dog

Black Diamond, WA

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Posted: 01/22/23 10:47am Link  |  Quote  |  Print  |  Notify Moderator

Although with the long list of repairs mods and upgrades adamis has done idk about suspension.
And being a 2wd it’s already softer up front. And if 24 year old springs, it’s mushy. Guaranteed.
Stiff springs up front, consistent well damped suspension travel in the rear with heavy slow rebound shocks. Imo is about the best to counter act the effects of a TC like load.

adamis

Northern California

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Posted: 01/22/23 11:14am Link  |  Quote  |  Print  |  Notify Moderator

Thanks all for the thoughts. So a few thoughts from people's comments.

1. The camper isn't all the way forward because it had rubber stops that are about 2.5" long that are mounted on the bottom front of the camper that go up against the front of the bed of the truck. I removed those but kept the spacing the same as I have a 2"x12" board that sits across the front of the bed and is notched to hug the camper and keeps it moving side to side. If I redid this with metal, I should be able to reclaim about a 1.5" to possibly 2" for the camper to move forward.

2. Those that think their truck doesn't porpoising probably just don't notice it. Some trucks will obviously handle this better than others. The easiest way to tell though is if you look up at the overhead portion of the camper right above your head while driving and see it moving up and down, that movement is because your frame is flexing as you drive. I get between 1" to maybe 2" of movement on rough roads. What I am also looking at is in the side view mirror, looking along the bed rail at the back where the tail lights are. You will see similar movement as the frame flexes. Now, short bed trucks or regular cab trucks obviously will have less flex. My truck being a crew cab, long bed with just a C channel frame obviously shows quite a bit of movement.

3. Buying a new truck is not in the cards. To get the same style of truck I'm looking at $70,000+, maybe closer to $90,000 by the time taxes are added in.We use the truck just a couple of times a year, otherwise it sits in indoor storage with the camper. Hard to justify a car payment nearing $1500 a month for a vehicle that gets less than 5000 miles a year. Now, if money where no problem, heck yeah I'd be down at the dealership buying a new truck but that ain't my life. That being said, I don't think I would end up with a new truck if we were out shopping. With two late teenagers and two toddlers, our future if I can persuade the Mrs. will likely have something like this in it.

4. I did just replace my shocks (Bilstiens previously that where rather worn out) with KYB Monomax shocks and I think that helped quite a bit. Would have liked to have some adjust-ability like the Rancheros have but they were not available at the location and time frame that I had to work with.

5. Getting back to the expense of strengthening the frame. Even if I spend $3000 to $5000 to have it done, I'm still way ahead of buying a new truck. The other thing is, my truck is only two wheel drive. Fine for California but my plan will be to start going to areas where there may be snow and ice and I don't want to be doing that in a 2 wheel drive truck. So the longterm plan is to take the truck to a 4x4 shop and have them do a 4x4 conversion on it and while they do that, they can add rigidity to the frame. Yeah, I know, it's extreme measures but even if I put $10k to $20k into this route, I'm still WAY ahead of a $70k to $90k new truck (and used trucks aren't all that much cheaper these days).


1999 F350 Dually with 7.3 Diesel
2000 Bigfoot 10.6 Camper


deserteagle56

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Posted: 01/22/23 02:35pm Link  |  Quote  |  Print  |  Notify Moderator

adamis wrote:


5. Getting back to the expense of strengthening the frame. Even if I spend $3000 to $5000 to have it done, I'm still way ahead of buying a new truck. The other thing is, my truck is only two wheel drive. Fine for California but my plan will be to start going to areas where there may be snow and ice and I don't want to be doing that in a 2 wheel drive truck. So the longterm plan is to take the truck to a 4x4 shop and have them do a 4x4 conversion on it and while they do that, they can add rigidity to the frame. Yeah, I know, it's extreme measures but even if I put $10k to $20k into this route, I'm still WAY ahead of a $70k to $90k new truck (and used trucks aren't all that much cheaper these days).


Methinks you would be money ahead to take your time and find a newer used 4x4 truck that's in great shape instead of converting the one you have to 4wd. I've been following conversion projects like this for some time and most end up spending a MINIMUM of $15,000, and that's doing the work themselves. Can't even imagine what a shop would charge to do the conversion. There's a lot more involved than just adding a front axle and a transfer case...little things like speedometer and odometer that will no longer work properly because a transfer case has been added.


1996 Bigfoot 2500 9.5 on a 2004 Dodge/Cummins dually


Grit dog

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Posted: 01/22/23 03:39pm Link  |  Quote  |  Print  |  Notify Moderator

^Can save your breath about doing the most financially smart thing to achieve the same end goal with this one….
This has come up before and the OP asks questions or solicits opinions that he’s already convinced himself is the way he’s gonna go even though it doesn’t make sense financially and/or practically.

adamis

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Posted: 01/22/23 04:50pm Link  |  Quote  |  Print  |  Notify Moderator

deserteagle56 wrote:

adamis wrote:


5. Getting back to the expense of strengthening the frame. Even if I spend $3000 to $5000 to have it done, I'm still way ahead of buying a new truck. The other thing is, my truck is only two wheel drive. Fine for California but my plan will be to start going to areas where there may be snow and ice and I don't want to be doing that in a 2 wheel drive truck. So the longterm plan is to take the truck to a 4x4 shop and have them do a 4x4 conversion on it and while they do that, they can add rigidity to the frame. Yeah, I know, it's extreme measures but even if I put $10k to $20k into this route, I'm still WAY ahead of a $70k to $90k new truck (and used trucks aren't all that much cheaper these days).


Methinks you would be money ahead to take your time and find a newer used 4x4 truck that's in great shape instead of converting the one you have to 4wd. I've been following conversion projects like this for some time and most end up spending a MINIMUM of $15,000, and that's doing the work themselves. Can't even imagine what a shop would charge to do the conversion. There's a lot more involved than just adding a front axle and a transfer case...little things like speedometer and odometer that will no longer work properly because a transfer case has been added.


For most trucks, that might be the case, but this truck has a few advantages that makes me think this route is worthwhile. To start with, the reason I picked a 7.3 is the smog equipment is non existent. I don't even have a catalytic converter on my truck and I'm still legal in California. I also have close to $10k in "goodies" in this engine, it pulls like a freight train and gets pretty decent mileage for what I need it to do. It is also very low mileage at 156k and by 7.3 standards, it's barely broken in. Just a list of the upgrades... Banks Exhaust Brake, Banks 3" exhaust, Larger KC Turbo, Larger Injectors, Upgraded High Pressure Fuel Pump, High Bypass Oil Filtration, Inline Fuel Line Filters (instead of in tank), Chipped, Air Bags, Onboard Air with 3 gallon tank and probably a half dozen other things I can't remember. All of this was done over time, not at once so the cost was spread out.

The second thing is that the 4x4 version of the 7.3 has leaf springs up front. Poor turning radius and harsh ride. So even selling it and getting a 4x4 version of the 7.3 means I'm dealing with those issues. True I could step up in truck generations but someone else pointed out that boxed frames didn't come along in Fords until 2017 so I'm now looking at a $30k+ truck that probably has quite a bit of mileage on it which also means the smog equipment is a ticking time bomb for an expensive repair that does nothing but allow me to pass smog. I'd rather spend $10k on my motor for upgrades versus $10k for the privilege of California letting me register the thing.

Assuming the right shop can be found (I have a lead on one I will be looking into) along with a donor truck, I can do the 4x4 conversion and have coil over suspension with a 7.3 motor with all the current upgrades and minimal smog requirements. The question is, can I find such a shop that can do it and do it right.

One factor that doesn't seem obvious in this is, why would I put $20k to $30k over time into a 24 year old truck? Because I'm doing it a little here and a little there as I have the money. It's easier to find $5k sitting around and coming up with an upgrade project for the truck. It is harder to find $1500 a month in the budget for 5 years to pay for a truck. The first option I can do as I have the funds to do it, the second I'm stuck on a treadmill.

JimK-NY

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Posted: 01/22/23 05:12pm Link  |  Quote  |  Print  |  Notify Moderator

Have you checked the CCC for your truck? If not you are likely to need more than just stiffening the frame and that 4WD conversion is just going to add more weight.

Grit dog

Black Diamond, WA

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Posted: 01/22/23 05:47pm Link  |  Quote  |  Print  |  Notify Moderator

JimK-NY wrote:

Have you checked the CCC for your truck? If not you are likely to need more than just stiffening the frame and that 4WD conversion is just going to add more weight.


No he hasn’t or he wouldn’t say it was rated for the payload he’s carrying.

adamis

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Posted: 01/22/23 08:47pm Link  |  Quote  |  Print  |  Notify Moderator

JimK-NY wrote:

Have you checked the CCC for your truck? If not you are likely to need more than just stiffening the frame and that 4WD conversion is just going to add more weight.


It took me a while to find it but Max Payload for the Crew Cab Dually Long Bed 2x4 appears to be 5355lbs and the 4x4 is 4910lbs. My camper according to the tag on it weighed 2906 and that included 50 gallons of water and 20lbs of propane. Going to a 4x4 conversion that would leave me 2000lbs for people and gear which would be way more than we would ever carry.

Being frank, the 4x4 conversion is something on the nice to do / want to do but not the need to do chart. Finding a good shop and a reasonable price may be the death of the idea. This goes for the frame boxing as well.

Getting back to the porpoising... I think the most realistic plan forward is to do what I can to move the camper for the extra 2". It may not help a ton but it is better than nothing.

* This post was edited 01/22/23 09:19pm by adamis *

Buzzcut1

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Posted: 01/22/23 09:39pm Link  |  Quote  |  Print  |  Notify Moderator

The camper tags lie. take the rig with a normal camping load on board to a cat scale and weigh it. Stop guessing, get a real world number.


2011 F350 6.7L Diesel 4x4 CrewCab longbed Dually, 2019 Lance 1062, Torqlift Talons, Fast Guns, upper and lower Stable Loads, Super Hitch, 48" Super Truss, Airlift loadlifter 5000 extreme airbags


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