Bouncing flatbed trailer

farmallboy15 · Sep 14, 2022

Has anybody ever got an awful suspension bounce while towing? My stock trailer is fine but the 14k flatbed bounces something awful when empty. With a few thousand pounds on it, it is fairly smooth. The trailer was fine on my old truck but anything over 45mph shakes the crap out of you on the super duty... My only guesses are that the trailer tires have finally gone bad or the rear shocks on the truck are bad.

jon f mn · Sep 14, 2022

Does it change from road to road or stay the same? Is this truck a different length?

Steve@Advance · Sep 14, 2022

Is there a difference in the hitch height between the trucks?

A friend of mine used to haul boats. He had a trailer that would shake when empty.

I went with him on a haul once, closest to motion sickness I ever came! It was relentless and horrible!

After having him stop a couple times, as soon as I got out the threat passed, but it came right back as soon as we were on our way. I told him to let me out at the next town, I'll take a bus home!

Instead we stopped and chained up the front axle. Smoothed it right out!

KCTractors · Sep 14, 2022

I have a 14,000 lb PJ that did that. The trailer has an adjustable coupler on it, so I dropped the coupler down one bolt-hole or two inches and no more bouncing.

tomturkey · Sep 14, 2022

definitely check out the tires, it only takes one bad one to set up a terrible vibration and stop you from going over 35-45mph. BUTTTT empty trailers do bounce. gobble

Geo-TH,In · Sep 14, 2022

I have the same problem between 30-45 mph with my 14k trailer
Put 3100# terramite on it and smooth as silk.
I paid to have the tires balanced. Didn't help.

I think part of the problem is tire pressure.
I think my tires are aired up to 80 or 90 psi and they bounce like a basketball. If you are not hauling a full load, try reducing tire pressure.

I think shock absorbers may help.
After selling a property 1.5 years ago I've only used my implement trailer twice..

If I have a long distance to travel empty, I reduce tire pressure to 25-30 psi. I carry a generator and air compressor in the truck to air up after it's loaded.

farmallboy15 · Sep 14, 2022

Truck went from an extended cab shortbed to a crew cab shortbed. Pretty well constant road to road. Called a trailer dealer. There first thought was the trailer tires

farmallboy15 · Sep 14, 2022

This is a 14k PJ as well. New truck is about 2 taller so I adjusted the trailer hitch up to match for the first load. Thats when I noticed the empty bounce. Lowered the hitch back for the second load. Bounce stayed. 11 year old tires are probably due for replacement will start there and see what happens.

Pete in Holland MI · Sep 14, 2022

If the trailer doesn't ride level, bouncing can happen. Son discovered this with his 14,000# trailer.

Have to remember that the trailer, springs, and tires are set up for a very heavy load. Empty, there isn't much forgiveness, and it can bounce like a basketball. Reducing tire pressure will help a lot when empty.

I have jacked up my trailer and spin the tires. Out of balance tires are given some weights, and that helps too.

Stephen Newell · Sep 14, 2022

Maybe it's because the deck is above the tires. I've never had a trailer bounce.

thomas h kwapiszeski · Sep 14, 2022

any chance someone put tire sealant in tires and it's broken loose and causing out of balance tires?

Tony in SD · Sep 14, 2022

Broken belts in the trailer tires or unbalanced trailer tires have done that with me. Most trailer tires have a speed as well as a load rating on them. If you exceed either or both, you stand a good chance on breaking a belt.

E.B. Haymakin' · Sep 14, 2022

I have a 14k trailer both axles have brakes and G rated tires. Empty it bounces, the springs and tires at rated pressure is going to cause it. But when I have 11k lbs of tractor on it, I don't have an overloaded trailer. Pulls great and safely loaded. If I'm empty I get beat up. There have been discussions on here about shock absorbing hitches. Search this forum

kcm.MN · Sep 14, 2022

One quick check, make sure one of your equalizers hasn't flipped.

Tslinger · Sep 15, 2022

11 years on a trailer tire is a long time... I'd be looking at doing them regardless at this point.
I do spend the little bit of extra to have my trailer tires balanced. All my trailers have pulled just fine empty since I've put on new shoes, and balanced them. When I bought them used, the tires were all mismatched, and who knows how old. New Maxxis radials all around calmed them right down. I run load range E on my 10k trailers, even though I could run D. Never hurts to have a little extra strength. They all run 70 psi.

BarnyardEngineering · Sep 15, 2022

(quoted from post at 11:24:49 09/14/22) Truck went from an extended cab shortbed to a crew cab shortbed. Pretty well constant road to road. Called a trailer dealer. There first thought was the trailer tires

So does this mean it started bouncing when you changed trucks?

If tires don't fix it, the next thing to look at are the axles. Bent, or misaligned. If the axles are not running parallel to each other, one axle is trying to go left, the other right, and when the forces exceed the tire grip, the trailer pops up. A load makes the tires scrub, so no pop.

montidale · Sep 15, 2022

I had the same problem with my 7 ton deck over trailer. I was afraid to pull it down the road empty. Put on a new set a tires and a smoothed right out

560Dennis · Sep 15, 2022

Try balencing the wheels

Bouncing flatbed trailer

farmallboy15

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jon f mn

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Steve@Advance

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KCTractors

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tomturkey

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Geo-TH,In

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farmallboy15

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farmallboy15

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Pete in Holland MI

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Stephen Newell

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thomas h kwapiszeski

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Tony in SD

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E.B. Haymakin'

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kcm.MN

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Tslinger

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BarnyardEngineering

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montidale

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560Dennis

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