Go Back   iRV2 Forums > TRAVEL TRAILER, 5th WHEEL & TRUCK CAMPER FORUMS > 5th Wheel Discussion
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 11-09-2013, 08:16 PM   #1
Junior Member
Join Date: Aug 2013
Posts: 1

What is chucking? I have a problem with my 5th wheeler bouncing on city streets. Feels like the truck and trailer get into some kind of oscilation and it feels like my truck will bounce off of the street. Any info to help?

danbarnes194 is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 11-10-2013, 09:20 AM   #2
Senior Member
caissiel's Avatar
Join Date: Oct 2011
Posts: 1,312
Originally Posted by danbarnes194 View Post
What is chucking? I have a problem with my 5th wheeler bouncing on city streets. Feels like the truck and trailer get into some kind of oscilation and it feels like my truck will bounce off of the street. Any info to help?
To soft springs and shock absorbers not doing their job. Might be the pin load also to light for weight of trailer. Very dangerous.

Barbara and Laurent, Hartland Big Country 3500RL. 39 ft long and 15500 GVW.
2005 Ford F250 SD, XL F250 4x4, Long Box, 6.0L Diesel, 6 Speed Stick, Hypertech Max Energy for Fuel mileage of 21 MPusG empty, 12.6 MPusG pulling the BC. ScangaugeII for display..
caissiel is offline   Reply With Quote
Old 11-10-2013, 09:59 AM   #3
Senior Member
road dogs's Avatar
Join Date: Jan 2013
Location: 7S5
Posts: 571
You don't provide much information to help folks answer your question. What TV do you have? What 5th wheel are you pulling? What is the pin weight, trailer weight, what kind of hitch are you using, what suspension mods, if any? If you can provide some info, I'm sure someone can help you....
2004.5 GMC SLT CCLB, Ride Rites, Turbo brake, EFI Live
2012 Arctic Fox 29 5T 5th Airborne, B&W, Prodigy
Papillon navigators Lily, Buddy and Willow
road dogs is offline   Reply With Quote
Old 11-10-2013, 08:29 PM   #4
Senior Member
hjsdds's Avatar
Join Date: Apr 2013
Posts: 330
Chucking is a physical phenomena, when you have uncoupled entities exerting unequal forces upon each other. The fact that you have a hitch in between means nothing, the truck and the trailer are two different entities held together by the hitch. Here's where the "fun" begins. You typical pickup will weigh between 6-8,000 pounds, an equal weight fifth these days is an entryway clunker, most better fifths you'll see are around 12K and they go up from there (sky's the limit). You hitch up 16-18K fifth behind that pickup and you have 2-3 times weight differential coming into that pickup and acting on the truck's rear suspension (through the hitch pin). Second, the fifth typically has much longer wheel base compared to the truck so it responds to motion differently. Thirdly, the brakes on the fifth are nor coupled directly to the truck brakes, you can fiddle with the controller to try to match them (in response time) but you can come close only at certain speed and certain brake pressure, the minute you increase (or decrease) the speed from the set point the adjustment goes out the window, the minute you put the hammer down hard, the adjustment goes out the window. Which means there will be typically a time lag before the brakes on the fifth start reducing the force vector pushing the truck. If you set the fifth's brakes on the aggressive side you will get the opposite, a jerk back.
We instrumented a hitch pin few years ago with a strain gauge,

to see what kind of forces we could see on the pin, the fifth and the truck during pulling, starting and stopping. There is a lot of weird stuff going on there and there is anywhere from two to three (or more) up and down and forward and back cycles before things settle down after any "disturbance", going over dip, pothole, braking or even just getting off the gas.
The bigger the truck/trailer weight differential the bigger the chucking problem. HDTs exhibit the least amount of chucking, even with big fifths

for two reasons. Typical HDT will weigh more or close to the fifth it pulls (even the "big ones") and second typical HDT conversion places the hitch behind the rear axle.

Which means that whatever motion is generated between the fifth and the truck gets dissipated behind the rear axle and into the rear axle, very little of it transitions forward into the cab area.

hjsdds is offline   Reply With Quote
Old 11-13-2013, 08:24 PM   #5
Senior Member
Ray,IN's Avatar
Join Date: Aug 2001
Location: North America somewhere
Posts: 13,905

The first item to check is the truck shocks. OEM shocks last about 25,000 miles of ordinary driving, towing a trailer cuts that severely. The pin weight of your 5er should be 18-25%, depending on mfgrs design.
When you replace shocks, several have lifetime warranties, Rancho, Bilstein, and several other brands. I bought Rancho shocks from Sears and installation. They have replaced them 2X now in 84,000 miles at no charge. I used to tow a 15,500# 5er with my dually, and it was obvious when the shock were failing. I would get chucking and the truck would bounce more than 2X when driving over potholes.
2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member,FMCA."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert the Constitution. "Abraham Lincoln"
Ray,IN is online now   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Featured Campgrounds

Reviews provided by

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 10:02 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.