How to stop the 'Porpoising' of the 5er?

rosepetal · 05-13-2012, 08:35 AM

Hi Everybody,

Mom just bought the Keystone Outback 5er and is pulling it with a f150 ecoboost, and while bringing it home we noticed (what seemed to us) as alot of porpoising of the rv. We were traveling down the highway and in the truck it seemed like there was just alot of bounce.

We talked to the rv dealer and they said that some people put airbags on their truck to reduce that and we've also read about the rollgard product that also is "supposed" to help as well. Now also keep in mind that the rv was pretty much empty other than carrying about 1/3 tank of water-maybe that had something to do with it. I just don't know.

Do ya'll have any experiences with the rollgard product or something like it-or putting airbags on the truck? Did it make a difference? Any info. would be great as we are new rv'ers.

Festus2 · 05-13-2012, 09:27 AM

Depending upon the condition and type of highway on which you were travelling, you might notice a bounce or porpoising each time you go over a segment of the concrete surface. As one end goes down, the other end goes up and it seems like you are being pushed along somewhat. If the road surface is really bad, you may also feel like you have a flat tire - the bouncing is so pronounced. Concrete, sectional highways are known to cause this.
Try taking it out on a section of paved asphalt highway - if there is one nearby -and see if you notice the same thing. If you do, then you can eliminate the type of highway construction as the culprit. Before running out and buying air bags, spring helpers or something similar, I'd check this out first.

rhagfo · 05-13-2012, 09:53 AM

Long Wheel base or short, and what is the max payload of the F150? You are around 1,200 of pin weight with that unit empty.

Did the unit sit level while towing? Does the TV have a towing package?

Outbackmel · 05-13-2012, 01:10 PM

Just returned from a 5,000 mile trip x country a month ago. Some roads are sooooo bad, UGH! Highways, 20 and 10 west were not too bad. Coming back on route 40 was HELL. They have not done anything to improve this road since day one. Potholes the size of Luray Caverns, buckled pavement, broken pavement, mile after mile after mile. Going out west, Shreveport, LA at 50mph felt like my TV was going to turn into scrap metal.

Returning, Memphis area ... no thank you.

Take the advice and find a smooth stretch of road and try it before making any radical decisions.

Yes, my TV and 36ft 5er are matched; loaded correctly, pin height correct, tire pressure excellent all the way around....sometimes it's just the road.

therink · 05-13-2012, 02:35 PM

The 298fre has a gvwr of 9,500 lbs. With 20% pin weight, that is around 1,900 of pin weight. What is the payload (not tow rating) of your F150? My guess is that either you are near or over the rating for your truck and that is what you may be experiencing with the ride harshness. I certainly wouldn't want to tow a trailer that heavy with a 1/2 ton. I Just my opinion.
Steve

Paddler · 05-13-2012, 04:39 PM

Just did a quick look at the specs on the Sydney and the F150 and....I suspect you do not have the optional HD Max towing package on your truck. If you have the HD Max towing package you could have a payload capacity of up to 2800 lbs. Without the HD Max towing package the payload capacity could be as low as 1600 lbs. Please check the vechicle payload capacity label that is on the driver's door or driver's door jam.

I tried to "fix" my overloaded 2500 with air bags...ended up buying a larger truck. Hope your problem was just rough roads.

LittleJoe · 05-14-2012, 12:41 PM

The much less than ideal roads is something not taken into consideration when people push and exceed the weight ratings on some rigs.
I am not pointing any fingers in particular, but when you have bad roads, and high head and crosswinds, you will wish you have more truck than you need, not less, guaranteed.

My BIL pulls a 42' triaxle 5ver TH with a SRW 3500 . It works well in good conditions but is an uncomfortable white knuckle hand full in bad conditions.

Jeffrey11 · 05-15-2012, 04:55 AM

If your Eco boost is the 3.5 you are most likely at the max capacity or over for that truck. You need to check the door tag and the trailer tag to be sure. You also need to check that the tires on your truck are inflated to the correct psi for the load and that the load range rating on them is sufficient. If you do no0t have the Max Tow package you are way over weight. The other risk you run besides the danger of the trailer driving the truck is getting stopped and weighed. Go to a truck stop and hit the scales and verify you are in or out of the tolerance for the weight and capacity of your truck.

Good luck

Goat815 · 05-17-2012, 09:28 PM

I agree with Jeff, you are prob over your limits and if I was a cop and saw a 1/2 ton pulling a 5er I would def pull them over. Plus pulling that kind of trailer is best suited for a diesel, not gas, my own opinion.

Regardless of how safe you drive or how much room you give yourself our even how flat the roads are, maxing out your truck is a hazard for you and your family and others on the road. Good luck in your travels and stay safe.

**JRTJH** · 05-18-2012, 05:58 PM

Quote:

Originally Posted by Goat815

I agree with Jeff, you are prob over your limits and if I was a cop and saw a 1/2 ton pulling a 5er I would def pull them over. Plus pulling that kind of trailer is best suited for a diesel, not gas, my own opinion.

Regardless of how safe you drive or how much room you give yourself our even how flat the roads are, maxing out your truck is a hazard for you and your family and others on the road. Good luck in your travels and stay safe.

It's certainly a good thing that you're not licensed to enforce law in Michigan. Making it a practise to stop half ton trucks pulling a 5er would get you more than a couple of complaints for harassment. There are a number of fifth wheels that are designed to tow with half ton trucks and it is not only safe and prudent to do so, but it is perfectly legal. Stopping vehicles as you suggest is "profiling" and would get you in deep "poop" around these parts.

Additionally, if you look carefully at the OP's first 3 posts, she informs readers that her mother has an "Eco-boost with max tow package of 11,300 lbs" so, speculation isn't really getting her any help with her porposing issue.

LittleJoe · 05-18-2012, 06:29 PM

DOT does not care or keep track of GVWR and towing rates on all the different small trucks out there. What they do care about and will check if they suspect and issue, is that the weight carried by each axle is not over the Max axle weight or TIRE rating weight rating.

The tow ratings etc are a very good guide, and if you stay within them , you should never be above a max axle rating.

rhagfo · 05-18-2012, 06:40 PM

Quote:

Originally Posted by Goat815

I agree with Jeff, you are prob over your limits and if I was a cop and saw a 1/2 ton pulling a 5er I would def pull them over. Plus pulling that kind of trailer is best suited for a diesel, not gas, my own opinion.

Regardless of how safe you drive or how much room you give yourself our even how flat the roads are, maxing out your truck is a hazard for you and your family and others on the road. Good luck in your travels and stay safe.

Not all 5er's are 40' long or weigh 16K#, there are several on the market sized for towing with 1/2 ton with a good tow package.

The "Porpoising" is most like caused as a result of a relationship with the wheel base of the TV and Trailer, they flex in resonance.

mguay · 05-19-2012, 02:38 AM

Reminds me of the shows I went to this winter that the salesman had written on the side windows of several 5ers "Half Ton Towable"

SAD · 05-19-2012, 04:08 AM

Quote:

Originally Posted by Goat815

...and if I was a cop and saw a 1/2 ton pulling a 5er I would def pull them over...

What law would they be breaking?

rhagfo · 05-19-2012, 10:38 AM

Quote:

Originally Posted by LittleJoe

DOT does not care or keep track of GVWR and towing rates on all the different small trucks out there. What they do care about and will check if they suspect and issue, is that the weight carried by each axle is not over the Max axle weight or TIRE rating weight rating.

The tow ratings etc are a very good guide, and if you stay within them , you should never be above a max axle rating.

Quote:

Originally Posted by Goat815

I agree with Jeff, you are prob over your limits and if I was a cop and saw a 1/2 ton pulling a 5er I would def pull them over. Plus pulling that kind of trailer is best suited for a diesel, not gas, my own opinion.

Regardless of how safe you drive or how much room you give yourself our even how flat the roads are, maxing out your truck is a hazard for you and your family and others on the road. Good luck in your travels and stay safe.

This looks like choosing the TV before the trailer. a 30' 5er is a fair amount to pull with a F150, or any 1/2 ton even with a MAX Tow package. There are 5er's out there that are sized for towing with a 1/2 ton, I just think you need to understand that you can't have a really big 5er with a 1/2 ton.

If you love the 5er, it is time to be looking at a 3/4 ton TV.

fivergeezer · 05-19-2012, 02:49 PM

My first 5ver was rated as half-ton towable but it was much happier behind my 1-ton diesel dually. I could easily forget it was there. I'd much rather be over-trucked than under.

Check the set-up of the hitch and pin box. Make sure the 5ver is as close to level as possible and that the truck is not squatting. If the truck is not over it's tow capacity you might benefit from some rear H.D. double action shocks and a rear anti-sway bar.

Most half-ton trucks I've seen come with little more than car tires and 2-ply side walls give you way too much flex.

While the numbers may add-up to half-ton towable, 3/4 ton will be better in the long-haul.

Exsailor · 06-02-2012, 09:16 AM

Pretty sure it's the roads, I've got plenty of truck and sometimes it jus happens

jje1960 · 06-02-2012, 09:24 AM

Quote:

Originally Posted by Exsailor

Pretty sure it's the roads, I've got plenty of truck and sometimes it jus happens

The dolphin can strike with any setup, anyone going down interstate 95 in Virginia, believe it's the James River will know that using cruise control over the bridge is a no-no.... I don't believe that anyone is going to advocate that I do not have enough truck to pull my SRX.... However we have found that really bad roads and cruise control will send the "Beast" swimming....! However, I'm definitely not a fan of towing out of spec's, if you are, then I'm not defending that practice, period.

**JRTJH** · 06-02-2012, 10:03 AM

jje1960, I agree with your statement regarding road conditions causing bucking or porpoising. When we had our Airstream, we towed with a 3/4 ton Dodge. That trailer weighed in at less than 5000 lbs and we were nowhere near our max in hitch weight, trailer weight or cargo weight, but on some roads through New Mexico and west Texas we actually wound up with sore abs from the bouncing in the cab. My DW had to cross her arms over her chest to keep from being in pain. I tried changing the tension on the equalizer bars, tried with and without sway control, tried adding and removing weight to the front of the trailer (there was a 30 gallon water tank under the front sofa) and no matter what I did, there was "stomach wrenching bouncing" with no way to stop or minimize it. Speeds from 30 to 70, no difference other than frequency of the ups and downs. We finally got off I-10 and travelled on the "back roads" with no bouncing at all.

Our current rig hasn't put us in that position yet, but I'm sure that sooner or later, we'll hit a stretch of road where the expansion joints are just the right distance apart to set up the all to dreaded up's and down's that are so annoying. As the truck hits the "uphill" side of the joint and the trailer is over the "downhill" side of a joint, they are going in different directions and the end result is a jolt in the middle. I don't care if you have a F450 and a trailer the size of mine or a 40 footer that weighs in at 16000 lbs, or if you're towing an ultralight travel trailer with an Explorer, once you get on a stretch of road with the right distance between the expansion joints, it's a matter of distance, not weight or size that makes for a very uncomfortable ride.

06-03-2012, 03:58 PM

I don't pull a 5er but I've experienced the porpoising, even when under rated payload. What other posts have said about the concrete roadways is right-on. But I still prefer to fix it. In my prev. TV I installed rear airbags and it made a massive difference. Felt like a totally different beast. As such, this weekend I installed airbags on my new 1/2 ton TV. This despite being ready to travel at well under the rated payload. I attribute some of this to the variable-rate rear suspensions that are softer and more forgiving until you get near the max payload.

Also make sure you are inflating your rear tires to the max cold PSI before you tow.

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