bounce

tawoo · 03-31-2015, 10:33 AM

I get trailer bounce even with my equalizer hitch on my 2014 Silverado 1/2 ton. The question I have is what would work better Bilstein helper springs or Hellwig shocks? Or would you suggest both?
Thanks!

eldermike · 03-31-2015, 10:42 AM

2 things to look at:
1) Proper tongue weight, distribution of loading in the TT affects this.
Loading weight behind the axles will lighten your tongue load. Not a good thing.
2) Level or slightly low in front of TT. If it's high in the front this is most of your problem.

TWP723 · 03-31-2015, 10:50 AM

Is the truck bouncing or the trailer? Is anything in the bed of the truck?

Scoutr2 · 03-31-2015, 10:54 AM

You are experiencing "porpoising," as it's called. Like eldermike said, take a look at how your trailer weight is distributed. (There's a reason they put the pass-thru storage in front.) If your water tanks are rearward of the axles, I'd advise you travel empty and fill them at your destination, if you can.

Also - your trailer should sit level when hooked to your tow vehicle. Being a little tongue-low is OK, but NEVER tongue high. If your hitch is the highest point, it can produce the bouncing you are talking about, and also induce wiggle. And too, you can't get the proper weight distribution and too much of your trailer weight will be thrown on to the trailer tires. Not a good thing.

And lastly - sometimes the harmonics between a trailer and tow vehicle are the culprit, when everything else has been done properly. If that's the case, try driving a few mph slower or faster and see if that helps. Sounds silly, but I have observed that on some roads (I-90 east across Minnesota, for one. Ugh! like a roller-coaster!)

tawoo · 03-31-2015, 11:25 AM

Thanks guys! Yes, my trailer and truck are level. I am pretty sure most weight is on the tongue and not the rear. However, we do load the bed of the truck with everything including firewood. That could be the culprit. If it is would those items I mention help? If I did install one or both would I end up with a too stiff ride when not pulling my camper?

TWP723 · 03-31-2015, 11:51 AM

Helper springs only work with a load and shouldn't jeopardize your ride. I have auxillary springs on my F250 (factory) and they don't even come into play without a load bearing down on them.

eldermike · 03-31-2015, 12:21 PM

Loading the bed of the truck is not a problem unless you are overweight on your rear axle. I have Timbrens on my truck but they do nothing unless I am loaded.

When you say your truck and trailer are level are you looking at it as a contiuous line from back of trailer to front of truck. That is common, but it's wrong. The trailer needs to be very slightly nose down no matter how the truck sits. From many years experience my best guess is this is your problem.

Adding anything to your truck to hold it up better will only make this worse because the nose of your trailer will only go higher.

Take your rig to a flat parking lot and measure from the front of the frame to ground and then from the back of the frame to ground. Adjust your hitch until you are lower in front. Your problem will then go away.

Camper_bob · 03-31-2015, 12:28 PM

I was getting a little extra bounce in the rear of my truck. I examined and adjusted my WDH to ensure it was set up properly, but I still got a little more than I was comfortable with.

I researched the Timbrens, the Helwigs, Firestone air bags, and the Roadmaster Active Suspension. I ended up choosing the RAS because it's a passive system, I wanted to bolt it on and adjust it and not worry about it again.

It did help a lot, and not just under load. The truck corners a lot better when empty now with the rear stiffened up just enough. The empty ride is not noticeably different, but it handles the load of my trailer better.

For reference, my truck is a 2012 GMC Sierra 1500 2WD and I'm towing right at my max payload with a couple hundred pounds under the rear GAWR.

Jagiven · 03-31-2015, 01:43 PM

what type of trailer do you have. From observation it seams like light weight single axle trailers bounce a lot more than dual axle trailers.

tawoo · 03-31-2015, 02:10 PM

It's a double axle 29 foot BH. No side to side sway only the bounce.

Jmooney · 03-31-2015, 06:05 PM

Where's the water tank. Forward , center or rear of axel?

**FPM III** · 03-31-2015, 08:55 PM

Do you experience "bounce" all the time or just certain times? The only time I have noticeable bounce is on worn concrete roads (or concrete roads that were asphalted over) at the expansion joints. On multi-lane roads, it can be especially prevalent in the rightmost lane. If you can move into the left lane, sometimes it will either go away or become less noticeable.

b1mmuo27 · 03-31-2015, 09:37 PM

I'm not understanding "tongue low" being good. I rolled a TT in 1998 on the I 75 & learned everything & then some about trailer pulling after that. Tongue below level leads to instability. The manual the came with trailers use to have the picture of the wrong way to pull it nose down as well.

Scoutr2 · 04-01-2015, 05:11 AM

My comment said "a little tongue-low is OK, but never tongue-high." I said that because it is nearly impossible to get your trailer perfectly level. With hitch shank adjustments being made in 1" increments, one position might be a little too high and the position below a little too low. Given those two choices, choose the one a little low. That doesn't mean to intentionally set up your rig tongue-low, but opt for that if you can't get it perfectly level.

rick danger · 04-01-2015, 05:27 AM

Quote:

Originally Posted by FPM III

Do you experience "bounce" all the time or just certain times? The only time I have noticeable bounce is on worn concrete roads (or concrete roads that were asphalted over) at the expansion joints. On multi-lane roads, it can be especially prevalent in the rightmost lane. If you can move into the left lane, sometimes it will either go away or become less noticeable.

Must be PA thing

I got on some concrete north of 80 /81 split on 81. I had to hold my stomach I was bouncing so much. Finally slowed down to about 40 with flashers and then had to deal with semi's blowing me around. I wondered if there was any way to put shocks on the trailer to help that.

Clayton4971 · 04-01-2015, 06:24 AM

Some of our roads are terrible ! Seems like the concrete roads are built with smaller sections probably cheaper to repair but also easier for the big trucks to damage. I have a f350 dually with air bags and a mor-ride pin box and still get that occasional road ! My question is do you get the bounce on all roads or just some ? If all I am sure their are things that you can do to help .

Iraqvet05 · 04-01-2015, 06:50 AM

I also experienced porpoising or bounce when we pulled our TT with a 1500. The bounce seemed worse where the asphalt road transitioned to concrete at overpasses. I never addressed the issue, just held the steering wheel in a death grip. I suspect the softer suspension of the 1500 that gives it a nice ride (compared to a 2500 or 3500) is an attributing factor. I'd check into CamperBob's suggestions.

goducks · 04-01-2015, 09:19 AM

Have you actually measured and weighed your setup?
You should start out by measuring the front fender height unhitched. After hitching up you want to return the front fender height to it's original height or as close as possible. forget about the rear.

Now go weigh your setup. You want to make sure you have 10-15% for tongue weight. 12+% is preferable.

Also if you're loading a lot of weight into the trucks bed then you might think about air bags. I used them along with a WD on our 1st TT and it rode like a Caddy.

The proper way to use bags and WD is to 1st load up the truck with all the gear you take. Now inflate the bags to bring the rear back to it's original height. Next hitch up and use the WD to setup your truck and TT.

I had the same bounce issue as you are having. The problem was that I had so much stuff in the trucks bed that I had to use 1000lbs bars to be able to lift the rear of the truck to transfer any weight. The tongue weight was only 500lbs. It made for a jerky-bouncy ride. After I put bags on the truck and went to 400-600lb rated bars the ride smoothed out tremendously.

SmokerBill · 04-01-2015, 09:48 AM

Quote:

Originally Posted by goducks

Snip...
The proper way to use bags and WD is to 1st load up the truck with all the gear you take. Now inflate the bags to bring the rear back to it's original height. Next hitch up and use the WD to setup your truck and TT.
Snip...

Not true for all airbags. I have Air Lift 60818 bags mounted inside the rear coil springs of my RAM. User manual specifies..

Quote:

Inflate your air springs to 35 PSI before adding the payload. This will allow the air cylinder to properly mesh with the coil spring. After the vehicle is loaded, adjust your air pressure down to level the vehicle and for ride comfort.

http://www.airliftcompany.com/conten...-704_60818.pdf

**FPM III** · 04-01-2015, 10:32 AM

Quote:

Originally Posted by rick danger

Must be PA thing

I got on some concrete north of 80 /81 split on 81. I had to hold my stomach I was bouncing so much. Finally slowed down to about 40 with flashers and then had to deal with semi's blowing me around. I wondered if there was any way to put shocks on the trailer to help that.

Nah, PA doesn't have a corner on that market, although it might be close. I've experienced bouncing in other states too! I know it's the road surface because when I cross a bridge or overpass it often stops, then resumes when I return to the road surface on the other side. I can't say I've ever experienced bouncing on the PA Turnpike, but I'm sure someone on this forum will call me on it.

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