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mcarter
podders Helping podders - pHp
Joined: 07 Apr 2016
Location: Greenbrier, TN
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Posts: 3419
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Topic: Should I adjust my towing setup? Posted: 13 Aug 2018 at 3:21pm |
Jato,
As I recall you don't use a WDH. So a hitch drop could help, with the WDH the OP has , they should be able to compensate for sway if properly adjusted.
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Mike Carter
2015 178
" I had the right to remain silent, I just didn't have the ability."
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john in idaho
Senior Member
Joined: 04 Nov 2014
Location: Eagle Idaho
Online Status: Offline
Posts: 611
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Posted: 13 Aug 2018 at 6:52pm |
I got rid of the last little bit of side to side movement in the mirror by changing out the Load range C tires with 50 lbs of air for load range E with 80 lbs of air pressure. I have found that my Ram PU likes to pull at 62 mph in tow-haul mode. And I hardly ever have to pass anyone. But we have real mountains to contend with.
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OldNeumanntapr
Senior Member
Joined: 23 May 2018
Location: CA
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Posts: 204
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Posted: 13 Aug 2018 at 7:24pm |
Originally posted by GlueGuy
Double nickel is the limit for vehicles with trailers in California. We've gotten used to going slow and easy, and enjoying the trip.
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I too live in CA and I’ve been passed by people pulling trailers that were doing at least 75. I’ve NEVER seen a CHP pull over a truck and trailer for speeding.
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jato
Senior Member
Joined: 23 Feb 2012
Location: Kewadin, MI
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Posts: 3237
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Posted: 13 Aug 2018 at 9:25pm |
Good memory Mike, you are correct as I have never used a WDH and you are again correct in saying the OP, by properly adjusting his WDH, he should be able to safely compensate for sway.
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God's pod
'11 model 177
'17 Ford F-150 4WD 3.5 Ecoboost
Jim and Diane by beautiful Torch Lake
"...and you will know the Truth and the Truth will set you free."
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clickscrazy
Senior Member
Joined: 09 Aug 2017
Location: FL
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Posts: 106
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Posted: 14 Aug 2018 at 7:37am |
So I think my plan will be this. Drop my WDH ring down one back to where it was (So it is not as tight) and run my Sway Control this time. Also, if I can, move a few more items up front I will.
We will see how that goes before dropping the ball.
I run 60lbs in my tires. I have the 2018 with 15" wheels.
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2018 R-Pod 171
2014 VW Touareg TDI
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mcarter
podders Helping podders - pHp
Joined: 07 Apr 2016
Location: Greenbrier, TN
Online Status: Offline
Posts: 3419
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Posted: 14 Aug 2018 at 7:57am |
Good plan, you'll get it right, takes some adjusting.
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Mike Carter
2015 178
" I had the right to remain silent, I just didn't have the ability."
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offgrid
Senior Member
Joined: 23 Jul 2018
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Posts: 5290
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Posted: 28 Aug 2018 at 5:41pm |
Sorry for the slow response, I've been off boondocking/off grid camping the past couple of weeks.
One issue with wd hitches is that they reduce the load on the rear axle of the TV by moving it to the front axle and to the trailer axle. To the extent that our rPod axles are, shall we say to be polite, not over-engineered for the application, you may want to either forego use of or or minimize the tension on your wd hitch springs to help reduce the rear axle load. This assumes your TV is robust enough to handle it.
Many of us however, myself included, chose an rPod so we could tow it with a midsize SUV. Then if we are boondocking we load them up with water, dual batteries, dual propane, solar etc. This requires use of a wd hitch and creates the need to find a balance point between hitch tension and trailer axle load. What you don't want to do is crank on your wd hitch until the TV "looks level" without first doing the math to know what that is doing to your trailer axle.
Here is a link to a nice calculator. The only missing item in it I could see was accounting for the wd hitch itself, they're not light. Add the hitch to the weight of your TV and you should be good to go.
https://www.ajdesigner.com/apptrailertow/weightdistributionhitch.php
In my case, I have a wd hitch rated for 1200 lbs, and if I crank that much tension on its springs my Highlander does indeed level out and looks nice, but I have added 230 lbs to my trailer axle load in the process. Not good.
I also highly recommend taking your rig fully loaded with everything and everyone for camping to a public scale and weighing all three axles, then two, then one. If you do that, with and without the wd hitch under tension you can directly see the effects. Also if you then drop your trailer and weigh your TV separately you can obtain your tongue weight without a special scale or the "bathroom scale procedure".
You will then have all the data you need to run the math and know if you have all your axles as well as your GCVW within limits and by how much. I used the free scale at my local waste transfer station for this and asking politely, but do try to go during a quiet time so you're not holding folks up.
In my case I was at about 3350 on the trailer axle with full tension on the wd hitch. By backing off to about 700 lbs tension on the hitch I dropped to 3250 on the axle while still having large reserves on both front and rear TV axles. However, as I still have some more mods (weight) to add to the rPod, I think an axle upgrade is probably in my future.
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold
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offgrid
Senior Member
Joined: 23 Jul 2018
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Posts: 5290
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Posted: 01 Sep 2018 at 6:22am |
I was curious so I spent a bit more time on the question of what else besides the trailer axle can be overstressed by excessive weight distribution hitch tension. Turns out there are a couple of additional problem areas.
First are the trailer frame rails. Consider that the trailer structure is basically two single ended cantilever beams supported at one end by the hitch and by the trailer axle inboard from the other end. The loading on these beams is more or less uniform along their length without the wd hitch load. By tensioning the wd hitch I am adding a point load 2.5 ft in from the hitch end. This load combination creates a max bending stress on the rails somewhere near where the tongue is welded to the main frame rails under the front of the trailer box. On my 179 at 1200 lbs tension on the wd hitch and a fully loaded trailer I am increasing the max bending stress on the frame rails by about 80% at that point.
So, is this additional frame loading a problem or not? I'm not a vehicle design engineer and am not interested in picking up any liability for taking a position on that. I will only say that taking a quick look on line at the g load factors typically used in vehicle frame design and checking the section properties of the rPod frame rails (which on my 179 are 0.1 in thick 4x2 box tubes) I wouldn't want to drive around very much with 1200 lbs tension on my hitch.
Second is the receiver hitch. Think of the wd hitch as the equivalent of a really strong guy shoving a big breaker bar into the receiver and rotating it to push the front wheels down into the pavement. There is a giant moment (torque) being applied at the receiver (3000 ft-lbs on my hitch at 1200 lbs tension). What could possibly go wrong? If you don't have a hitch rated for wd use here's what can happen. And no, that's not my Highlander. So, be sure your hitch (and its attachment to your TV) is rated for wd use. This one wasn't.
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold
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GlueGuy
Senior Member
Joined: 15 May 2017
Location: N. California
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Posts: 2632
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Posted: 01 Sep 2018 at 9:37am |
Originally posted by offgrid
First are the trailer frame rails. Consider that the trailer structure is basically two single ended cantilever beams supported at one end by the hitch and by the trailer axle inboard from the other end. The loading on these beams is more or less uniform along their length without the wd hitch load. By tensioning the wd hitch I am adding a point load 2.5 ft in from the hitch end. This load combination creates a max bending stress on the rails somewhere near where the tongue is welded to the main frame rails under the front of the trailer box. On my 179 at 1200 lbs tension on the wd hitch and a fully loaded trailer I am increasing the max bending stress on the frame rails by about 80% at that point. |
I believe that the tension can not be that high. To begin with, the tongue weight on a fully loaded RP-179 is going to be in the neighborhood of 500 lbs. That means the maximum weight you can distribute is 500 lbs. Some portion of that tongue weight gets transferred to the front wheels. The amount is determined by the length of the moment arm, which is driven by the distance between the WDH and the rear wheels of the TV. Conversely, some of that tongue weight is transferred back to the trailer wheels. Because the moment arm is much longer, the amount of weight transferred back to the trailer wheels will be much smaller.
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bp
2017 R-Pod 179 Hood River
2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost
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BVK
Newbie
Joined: 21 Jul 2018
Location: Pacific NW
Online Status: Offline
Posts: 21
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Posted: 01 Sep 2018 at 10:09am |
Originally posted by GlueGuy
Double nickel is the limit for vehicles with trailers in California. We've gotten used to going slow and easy, and enjoying the trip.
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Oh, I like that rule.
In parts of Washington, slow turn-outs are enforced for vehicles with 5+ vehicles behind them. With people driving as if the 5mph-over rule is real, it can prove for some stressful times. I just remind myself that, if I'm going the speed limit, I'm not a slow vehicle.
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2012 RP-171 HRE, 2006 F-150
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