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11-02-2018, 11:26 PM
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#1
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Member
Name: Kevin
Trailer: In the market
South Carolina
Posts: 74
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Dancing truck while towing
So I find it annoying as hell. The road conditions are crap. Have a WDH installed and working well. But when I hit a road pothole the truck likes to jump all over the place. What I mean is, I can get a serious porpoising effect, or a jump of an inch. Never loose control, but it can make you seasick from how it moves at 60 mph speed. RV trailer is 5000 pounds. Tundra truck has 7000 pounds towing capacity.
Shocks are all over 100k miles on them, but unloaded the truck rides fine.
Could just be the roads I suppose. Air pressure is good in all the tires.
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11-02-2018, 11:29 PM
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#2
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Senior Member
Trailer: Escape 17 ft
Posts: 8,317
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Slow down?
__________________
What happens to the hole when the cheese is gone?
- Bertolt Brecht
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11-02-2018, 11:31 PM
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#3
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Member
Name: Kevin
Trailer: In the market
South Carolina
Posts: 74
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Quote:
Originally Posted by Glenn Baglo
Slow down?
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Trust me I do!! Lol. My speed can be 45mph to 60mph, on roads with 65 to 70 mph signs.
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11-02-2018, 11:39 PM
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#4
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Senior Member
Trailer: Escape 17 ft
Posts: 8,317
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You say WDH is working well. If the truck is dancing, why would you think that? Perhaps you should have somebody check the WDH.
I expect you'll be hearing shortly from others recommending heavier springs or air bags for soft rear suspension on Tundra.
__________________
What happens to the hole when the cheese is gone?
- Bertolt Brecht
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11-03-2018, 01:56 AM
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#5
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Senior Member
Name: Dave
Trailer: Casita SD17 2006 "Missing Link"
California
Posts: 3,738
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Quote:
Originally Posted by offroad
Shocks are all over 100k miles on them, but unloaded the truck rides fine.
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Kevin, with 100K on the shocks they've got to be close to the end of a useful lifespan. I'd be replacing those just as maintenance for a wear part and see if that takes care of it.
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11-03-2018, 04:37 AM
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#6
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Senior Member
Name: John
Trailer: Escape 21, behind an '02 F250 7.3 diesel tug
Mid Left Coast
Posts: 2,937
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also, make sure your tire pressure is pumped up to something suitable for the actual load on the truck axles.
but yeah, I'd be checking that WDH, ensuring its set properly. load the truck, measure the spacing from top of tire to rear fender and same in front, hitch up with the WDH and measure it again... the rear shouldn't sag more than about an inch more than the front if the WDH is properly setup. the front absolutely should not be going UP, or going down more than the rear, or the WDH spring tension is all messed up.
On my Tacoma TRD Offroad, I had a lot of porpoise action, a WDH stopped it dead, but so did properly adjusted airbags (which I got for carrying heavy loads when not towing, but they turned out to massively help while towing. also better shocks (bilstein 5100) helped the ride quality a lot.
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11-03-2018, 06:23 AM
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#7
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Senior Member
Name: Shelby
Trailer: Casita SD
Tennessee
Posts: 1,087
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That's heavy for a FGRV, seems only Bigfoot approaches that weight. You might check that you are within cargo weight limit, got to be a heavy tongue. At that mileage you may need shocks. Check that you have LT tires, not P. Even optimized you may be pushing the limit with a Tundra.
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11-03-2018, 07:51 AM
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#8
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Senior Member
Name: Steve
Trailer: 2018, 21ft escape— 2019 Ram 1500 Laramie
NW Wisconsin
Posts: 4,500
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I had similar issues when towing with my 1999 Dodge 1/2 ton V6 truck
( similar mileage)
Local Mechanic said shocks were bad and suggested I replace them with heavy duty load leveling shocks ( cheap & fast & simple)
It did make the truck ride better when towing and they weren’t too bad when not towing . I eventually came to the conclusions that some vehicles tow well and others don’t and dumped the truck
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11-03-2018, 10:48 AM
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#9
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Senior Member
Trailer: Scamp 16 ft Side Dinette
Posts: 1,279
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What's it like on concrete roads with expansion cracks every 6 ft or so?
Does it get into a steady bounce? That is called "Natural Frequency" A combination of the spring rates and geometry of the whole rig.
Contributing factors can be: too much air pressure in the trailer tires, a loose hitch ball/ball mount joint, weight distribution, etc.
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11-03-2018, 11:14 AM
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#10
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Senior Member
Name: Carl
Trailer: 2014 16 scamp side dinette/Rav4 V6 Tow pkg.
Pennsylvania
Posts: 578
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When i had my truck, this is before i new anything about towing. little over 100,000mi,on truck. I would drive over a ripple section of asphalt and the truck would be jumping like you said. Took it in for inspection and they said shocks/tie rods were bad, i forget which. Changed them and the truck ran like new. Carl
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11-03-2018, 11:30 AM
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#11
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Senior Member
Name: John
Trailer: Escape 21, behind an '02 F250 7.3 diesel tug
Mid Left Coast
Posts: 2,937
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re: natural frequency... GOOD shocks tuned to the spring rate and axle weights should stop that cold.
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11-04-2018, 01:36 AM
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#12
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Member
Name: Kevin
Trailer: In the market
South Carolina
Posts: 74
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My WDH is the spring bar with chains type. Brand is PRO SERIES. Have been told that can have a lot of spring in it. And to try changing to ANDERSON hitch WDH.
So could be old shocks with not enough dampening (need heavy duty); or switch WDH.
Looks like I might be calling some trailer hitch shops to get opinions.
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11-04-2018, 01:38 AM
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#13
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Member
Name: Kevin
Trailer: In the market
South Carolina
Posts: 74
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Dancing truck while towing
Quote:
Originally Posted by John in Santa Cruz
re: natural frequency... GOOD shocks tuned to the spring rate and axle weights should stop that cold.
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That’s an interesting direction. So would need to find a shop that understands shock geometry/physics under heavy load.
This video shows what seems to be happening. https://youtu.be/6Z-2WKwsLTw and maybe heavy duty bilstein shocks will help with this.
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11-04-2018, 10:12 AM
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#14
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Senior Member
Trailer: Escape 17 ft
Posts: 8,317
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Quote:
Originally Posted by offroad
My WDH is the spring bar with chains type. Brand is PRO SERIES. Have been told that can have a lot of spring in it. And to try changing to ANDERSON hitch WDH.
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Escape was selling the Andersen WDH. Stopped after too many complaints. It still sells the Pro Series, which is what I have used for ten years without issues.
I suspect that your WDH is not installed correctly or that the bars are hooked on the wrong link.
__________________
What happens to the hole when the cheese is gone?
- Bertolt Brecht
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11-04-2018, 10:20 AM
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#15
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Senior Member
Trailer: 1988 16 ft Scamp Deluxe
Posts: 25,697
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Did I miss what trailer you're towing? Hummm, if you post that, perhaps someone towing a matched set would post and be more helpful. Because right now it appears we're throwing noodles at the wall and hoping something sticks...
__________________
Donna D.
Ten Forward - 2014 Escape 5.0 TA
Double Yolk - 1988 16' Scamp Deluxe
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11-04-2018, 12:03 PM
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#16
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Junior Member
Name: Linda
Trailer: Currently Shopping
Virginia
Posts: 11
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Dancing truck while towing
You might look at the weight distribution in your trailer. If it is off balance, it can cause these issues.
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11-04-2018, 12:49 PM
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#17
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Senior Member
Name: John
Trailer: Roamer 1
Smith Valley, Nevada
Posts: 2,879
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Kevin,
Porpoising is a specific problem related to under-damped, low velocity compression and extension of the shocks. It is worsened by worn out shocks and/or velocity sensitive shocks.
The first thing to do is replace the shocks. Worn out or velocity sensitive shocks allow porpoising. So don't get just any kind as replacements. For instance, Bilsteins, which are very good shocks, work poorly for towing because they are velocity sensitive. Porpoising is very low velocity movement and can be outside the speed range of effective damping.
In my experience the best shocks for towing, or variable loads, are Rancho 9000 series adjustable shocks. You can tune them with the twist of a knob to be either soft for non towing or very stiff to prevent the problem you describe.
Do not just go to a cheap replacement, or to stock shocks that are designed to make the truck ride smooth when unladen. You need adjustable towing shocks.
__________________
I only exaggerate enough to compensate for being taken with a grain of salt.
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11-04-2018, 08:43 PM
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#18
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Senior Member
Name: JD
Trailer: Scamp 16 Modified (BIGLY)
Florida
Posts: 2,445
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I did not notice what kind of truck you have but perhaps a set of Gabriel air shocks and a compressor to adjust the ride height and add some damping.
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11-04-2018, 10:15 PM
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#19
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Senior Member
Name: John
Trailer: Escape 21, behind an '02 F250 7.3 diesel tug
Mid Left Coast
Posts: 2,937
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Quote:
Originally Posted by offroad
That’s an interesting direction. So would need to find a shop that understands shock geometry/physics under heavy load.
This video shows what seems to be happening. https://youtu.be/6Z-2WKwsLTw and maybe heavy duty bilstein shocks will help with this.
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the problem is, those 'good' shocks are very expensive... you find them on higher end motorcycles, and as aftermarket shocks for offroading (king, fox, etc), and racing. they typically have external reservoirs and offer adjustable low speed, high speed damping on both compression and rebound. tuning them is an art form.
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11-05-2018, 06:02 AM
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#20
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Senior Member
Name: Shelby
Trailer: Casita SD
Tennessee
Posts: 1,087
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Quote:
Originally Posted by Donna D.
Did I miss what trailer you're towing? Hummm, if you post that, perhaps someone towing a matched set would post and be more helpful. Because right now it appears we're throwing noodles at the wall and hoping something sticks...
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He's been coy but at 5000 lbs seems it has to be a Bigfoot.
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