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Old 11-27-2012, 03:19 PM   #43
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Rumship,

The 14,000lb hitch and the 12,000lb hitch use the same spring bars. The 12,000lb would have sufficed for me (my tongue weight can exceed 1000lbs), so being that they both use the same bars, I went with the 14,000lb model because the head unit is beefier.

I should add that my trailer is actually an Avion. It's tongue and frame are much heavier than my Excella's was. It can take a lot more stress without hurting it. With an older Airstream with the 4" tongue (like my '77 Excella had), you have to be very careful to not use too stiff a spring bar.

You can always machine the bars down if you want them more flexible. I've PM'd a few folks on here telling them how to do that. But basically, you could take the 12,000lb model that you had, and take the bars to a machine shop. You'd just need to match the stiffness of the 1000lb bars. If the thicknesses were the same, you'd just machine an hourglass shape into the bars, removing a little material equally from the top and bottom surfaces, and blend it out over a smooth area. For example, if the 1200lb bars were 1.5" tall and the 1000lb bars were 1.25" tall, and both were the same width (just say 1" for an example), then you'd machine .125" off the bars top and bottom, about midpoint between where they go into the head unit and where they contact the L-brackets. Taper it back to full thickness smoothly on either side of the minimum height area. So maybe spread the hourglass shape out about 12" total; say 6" on either side of the midpoint. And you've got it.

If the bars are different thicknesses, then you need to do a little math and make the Moment of Inertia's of the bars match, but the formula is just I=bh^3/12.

That is, Moment of Inertia (Stiffness) = (Base * Height ^3 )/12

So say you have the 1200lb bars and they are 1.5" tall and 1" thick. You want to match up to the 600lb bars. Say they are 1.15" tall and 0.875" thick. You have to calculate the stiffness of the 600lb bars first. Then you would calculate what height to machine our 1200 bars too.

So in this example, the moment of inertia of the 600lb bars are bh^3/12 = { (0.875in) * (1.15in)^3 } /12 Do the math and the answer is 0.111in^4.

So, we want to match 0.111in^4. That is the I value. So again I=bh^3/12. So:
0.111in^4 = { (1in)*h^3 } /12
Do the math and h = 1.1in.

So you take your bars to the machine shop and remove (1.5in-1.1in)=0.4in of height to make the hourglass shape. If you have the bars hitting the L plates at 31" back from the pivot point, put the center of the hour glass somewhere around the middle point. So at 15.5" from the pivot point, machine off 0.2" from the top surface and 0.2" from the bottom surface. Blend that 6" in either direction back to full bar thickness. Now you've got an hourglass shape in your spring bars, centered between the L-brackets and the pivot points, that spreads smoothly over a 12" wide space (6" on either side of the 15.5" mark) and goes from 1.5" down to 1.1" and then back to 1.5" smoothly. Put a paint job on her and call it good.



Anyway, I don't want to put you all to sleep with the math and stuff, but you can make it work. The problem is that the 600lb bars or even the 1000lb bars (to my knowledge anyway) won't fit in the 12,000lb or 14,000lb head. But it's really an easy modification to make.

Inland Andy has discussed overhitching for years and he makes excellent points with it. It's better to have a springier bar deflected 2" to get you the proper ride height than a megastiff bar deflected 1/2" to do the same weight transfer. The heavier your tow vehicle, the less weight distribution you need. I don't want to get too far off topic here so will let it go at that....but you guys are on the right track.

Bob, my "Super Doublers" don't flex a bit

I have been very happy with my Equal-I-Zer.
I think all you guys that bought one have a solid hitch. If a person takes the time to learn how to set it up properly (and I've read many dealers don't know how to do this....), they'll have a nicely towing setup.

See ya on the road,
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Old 11-27-2012, 07:04 PM   #44
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The L brackets on ours have the set screw. They did slip several years ago and I just tightened the bolts a bit (just short of bending them) and they haven't slipped since.

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Old 11-27-2012, 08:01 PM   #45
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Quote:
Originally Posted by JimGolden View Post
Rumship,

The 14,000lb hitch and the 12,000lb hitch use the same spring bars. The 12,000lb would have sufficed for me (my tongue weight can exceed 1000lbs), so being that they both use the same bars, I went with the 14,000lb model because the head unit is beefier.

I should add that my trailer is actually an Avion. It's tongue and frame are much heavier than my Excella's was. It can take a lot more stress without hurting it. With an older Airstream with the 4" tongue (like my '77 Excella had), you have to be very careful to not use too stiff a spring bar.

You can always machine the bars down if you want them more flexible. I've PM'd a few folks on here telling them how to do that. But basically, you could take the 12,000lb model that you had, and take the bars to a machine shop. You'd just need to match the stiffness of the 1000lb bars. If the thicknesses were the same, you'd just machine an hourglass shape into the bars, removing a little material equally from the top and bottom surfaces, and blend it out over a smooth area. For example, if the 1200lb bars were 1.5" tall and the 1000lb bars were 1.25" tall, and both were the same width (just say 1" for an example), then you'd machine .125" off the bars top and bottom, about midpoint between where they go into the head unit and where they contact the L-brackets. Taper it back to full thickness smoothly on either side of the minimum height area. So maybe spread the hourglass shape out about 12" total; say 6" on either side of the midpoint. And you've got it.

If the bars are different thicknesses, then you need to do a little math and make the Moment of Inertia's of the bars match, but the formula is just I=bh^3/12.

That is, Moment of Inertia (Stiffness) = (Base * Height ^3 )/12

So say you have the 1200lb bars and they are 1.5" tall and 1" thick. You want to match up to the 600lb bars. Say they are 1.15" tall and 0.875" thick. You have to calculate the stiffness of the 600lb bars first. Then you would calculate what height to machine our 1200 bars too.

So in this example, the moment of inertia of the 600lb bars are bh^3/12 = { (0.875in) * (1.15in)^3 } /12 Do the math and the answer is 0.111in^4.

So, we want to match 0.111in^4. That is the I value. So again I=bh^3/12. So:
0.111in^4 = { (1in)*h^3 } /12
Do the math and h = 1.1in.

So you take your bars to the machine shop and remove (1.5in-1.1in)=0.4in of height to make the hourglass shape. If you have the bars hitting the L plates at 31" back from the pivot point, put the center of the hour glass somewhere around the middle point. So at 15.5" from the pivot point, machine off 0.2" from the top surface and 0.2" from the bottom surface. Blend that 6" in either direction back to full bar thickness. Now you've got an hourglass shape in your spring bars, centered between the L-brackets and the pivot points, that spreads smoothly over a 12" wide space (6" on either side of the 15.5" mark) and goes from 1.5" down to 1.1" and then back to 1.5" smoothly. Put a paint job on her and call it good.



Anyway, I don't want to put you all to sleep with the math and stuff, but you can make it work. The problem is that the 600lb bars or even the 1000lb bars (to my knowledge anyway) won't fit in the 12,000lb or 14,000lb head. But it's really an easy modification to make.

Inland Andy has discussed overhitching for years and he makes excellent points with it. It's better to have a springier bar deflected 2" to get you the proper ride height than a megastiff bar deflected 1/2" to do the same weight transfer. The heavier your tow vehicle, the less weight distribution you need. I don't want to get too far off topic here so will let it go at that....but you guys are on the right track.

Bob, my "Super Doublers" don't flex a bit

I have been very happy with my Equal-I-Zer.
I think all you guys that bought one have a solid hitch. If a person takes the time to learn how to set it up properly (and I've read many dealers don't know how to do this....), they'll have a nicely towing setup.

See ya on the road,
Hi Jim,

I don't think you are off topic at all...this thread is about the E hitch. I like how you think. I have often thought about the same thing...but with a lot less math. I believe my 1,000 lb. bars are actually square. Without using the hour glass shape you mention, I would just leave the two ends the same, as there is really no option.

About an inch from the socket, and about an inch or two from the place where the sharpest turn would slide the bar on the L-bracket, I would just drop down to the dimension of the next smallest bar. For the sake of conversation, if my current 1,000 lb. bar is 1-1/2" square, I would have the middle section as described, milled down to 1-1/4" square...or what ever the 800 lb. bars are.

So instead of 800 lb. bars they would be somewhere more than 800 but a lot less than 1,000. As long as they were consistent on both sides it should work.

I have moved my L-brackets out to the farthest measurement recommended...it think it is 32", to allow for a bit more flex...seemed to make sense to me and seems to help with the ride. But I still don't get alot of bow when hitched up, less than an inch.

I really have no comparison on how a trailer should ride, but I often see a jumpy trailer in the rear view mirror...I do live in Southern Cal though, and certain sections of our freeways are a bit grim... (I never understood the repeated comment that A/S's like a "soft ride"...what trailers like a "stiff ride"? Is there a brand?)

Has anyone ever actually done this? I have heard it mentioned on several posts, but never seen pics or read a review. Jim, will you be the first?

And Bob...great thread.
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Old 11-27-2012, 08:24 PM   #46
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Quote:
Originally Posted by No. 13 View Post

I have moved my L-brackets out to the farthest measurement recommended...it think it is 32", to allow for a bit more flex...seemed to make sense to me and seems to help with the ride. But I still don't get alot of bow when hitched up, less than an inch.

Hi, my "L" brackets were originally installed at around 29"s and I moved them back to the max, 32"s. At the max / 32"s it gives the spring bars more leverage and more room to flex.
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Old 11-27-2012, 08:46 PM   #47
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I was having problems with the L brackets walking as well; I tried the 3rd bolt trick mentioned above, which has helped, but as the L brackets and link plates were warped to a point that I couldnt straighten them, still had the problem.

I replaced the L brackets and link plates a couple months ago, and found that the manufacturer has made some changes to the design from when I bought the hitch in 2010 - the link plates are thicker (but not to the extent as Jims!) and the method by which the L brackets are mounted changed slightly. On last trip, they walked slightly, but probably need a little more tightening.

Manufacturer's website has new part numbers and drawings for the updated plates.

Steve
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Old 11-27-2012, 08:56 PM   #48
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We have a 2008 Tahoe and tow a 2012 20 foot. I bought the 600lb rating because when we had a 2008 19, it came with the 1000lb bars and it poped rivits on the trailer. I was not going to let that happen with our new one. I also have the plastic pads and I did noticed the difference without them. All I did was torque the hitch head bolts a little more and it seems to work fine. The problem with this vintage Tahoe, (GMT 900) is that GM installed the hitch in the bumper and therefore need a longer drop bar. I feel it moves around some and someone mentioned about stainless shims in their receivers. I sure would like to know more about that. Otherwise I've had a few other brand trailers and the EQ hitch made all the difference for me so I'll continue to use it. It is simple to install and remove at any angle.
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Old 11-28-2012, 12:12 AM   #49
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" *I have moved my L-brackets out to the farthest measurement recommended...it think it is 32", to allow for a bit more flex...*seemed to make sense to me and seems to help with the ride. But I still don't get alot of bow when hitched up, less than an inch. "


They will flex as you are driving. Acting a bit like a shock absorber so not to over stress the rig.
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Old 11-28-2012, 08:36 AM   #50
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Hitch modifications

Here are the things I have done to make my Equalizer perform easier/better for me. The extra bolt you see in the L-pin pic is a smaller bolt I added to maybe keep the L brkt from getting lost if the set screw loosens.
Attached Images
    
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Old 11-28-2012, 09:42 AM   #51
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We were happy with our dealer installed (read that spendy) EQ brand hitch until after a couple of short trips when the L-brackets started moving around on the frame.

Hmmm read the blanking manual - apparently the technician did not read it .... as the cross bolt was already leaving a mark on the propane line as the L-bracket moved from a purely perpendicular position to a more diagonal position. Easy fix to move into proper bolt position... move propane line bracket, and shield the line from any further abrasion with PVC tubing - oops, small bend in propane line is not a problem.

Next, I checked the coupler to L-bracket distance where the manual says that 32" is optimum. I changed it from the 27" as originally installed by the "technician" to the 32 as spec'd in the manual. It makes more sense to me that if the support points are further apart allowing more flex in the load bars, then the ride will be a bit smoother for the AS. I was also sold a 10K EQ brand hitch for a rather light weight Bambi. Reading on this forum that heavier duty load bars might stress the A-frame and potentially pop some rivets, I next attacked the bar stiffness / thickness as I posted on here some time ago. (The lighter bars are not interchangeable with my head) You can read the process in those old posts, but the bottom line is that I re-contoured the bars with a smoothe reduction in thickness all around by grinding off some corner material. So, I now have something between the 10K and 6K capacity load bars. The bars have been sanded, re-primed, and sprayed with hardening bed-liner via rattle can. I also have them marked with a red dot on the top of the bar for right and a white dot for left. The bed liner coating (except for the last 3.5" where the bars ride on the L-brackets & pads) makes cleanup much easier when stowing the bars after driving through mud, rain, or snow. For storage, we also use 2 lengths of PVC electrical conduit (gray) with caps on one end of the two tubes. I drilled one small hole in each end of the tubes to hold the tubes together with a short length of line through the holes - thus preventing the tubes from rolling around in the back of the TV. The last mods were to grind off and round the bottom of the excessively long shank (needed when we went from a 1/2 T to 3/4 T TV) as well as the two 5" x 3/4" shank bolts attaching the head to the shank. I had left a great deal of leg skin on the bolt ends before cutting them flush with the nuts. They are hardened bolts, so grind with care - hacksaw was of no use.

To monitor movement of the L-brackets on the frame, I have drilled through the surface paint (1/8" bit) and barely into the metal of the frame where the front of the L-bracket meets the frame. A dot of contrasting paint (wife's old fingernail polish works well) in the resulting crater / dimple serves as a "wittiness mark" to check for any L-bracket movement. It is easy to tell if there is any movement if the dot "vanishes". It also occurred to me that the closer the load bars were to meeting the L-brackets' mating surface in a parallel manner, the less vibration would be transferred into the L-bracket / frame juncture thus minimizing movement of the L-brackets on the frame. As soon as I rectified that issue by minimizing the offset, more surface of the bars was evenly exposed to the L-bracket & pads and the "walking" around of my L-brackets ceased to be a problem. One bolt hole up or down to adjust the L-brackets for load does not seem to make a large difference in the mating surface now so long as the initial downward tilt / # of washers put you into the proper equalization range.

There was much measuring and re-torquing during the process over the first season and I am glad that the the EQ brand offers all of those adjustments. We spent 48 days on the road this past season with out a hint of a towing issue. When not "hitched up", we cover our freshly greased ball with the cut off end of a large plastic pill bottle to save the pants legs ... incidentally, Progress Mfg will send you new stickers for your hitch & bars simply for the asking. We keep ours looking like new that way.
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Old 11-28-2012, 10:54 AM   #52
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Quote:
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Thanks for starting this thread.

I have a 2007 27' Safari SE. My TV is a Dodge Ram 1500 quad cab. I bought the trailer used one year ago. The previous owner had a Equalizer Hitch that came with it. It has 1200lb. spring bars. I noticed that when the trailer when over bumps it snapped back quickly causing shock to the trailer and things moved inside. When I investigated I found the hitch was not set up properly. After a proper set up the performance improved, however there was still shock to the trailer when I went over bumps. I bought a Equalizer hitch with 1000lb. spring bars and installed it properly. This again improved the performance and reduced the shock to the trailer. I think I now have the best hitch for my trailer and TV, and am satisfied at this point.

I would like to hear from other owners that have a 27' trailer and TV similar to mine. I want to learn from your experience to see if I need to do anything else that would improve my towing.

Thanks,
Henry
Henry.

Your absolutely correct when you say "bigger is not always better".

You now have experienced a better ride for the trailer by down sizing the hitch bar rating.

Also, keep in mind that the equalizer bars bend the least of all other bars of the same rating, with the same loading. That means that more shock from the same bump is transfered to the trailer when using Equalizer bars.

If you now continued the down sizing to 800 and then to 600 pound bars, you will find that the shock continues to decrease as you decrease the ratings.

Hitch bar ratings are all to many times chosen to match the tongue weight. That is not how it works.

The tow vehicle type must also be included in the math. The heavier the tow vehicle duty, the lighter rating the bars should be.

Example: 800 pounds of tounge weight would use a 1000 pound hitch bar with our old time large cars. That would drop to 800 pounds when used with a 1/2 ton truck. The rating would further drop to 600 pounds when used with a 3/4 ton or greater truck.

Those tests were done some 40 years ago, and still apply, since Physics don't change.

If heavier was better, then lets talk about using railroad track for bars. Obviously, most everyone would agree that would be "crazy".

So where then, is the line drawn that says "whoo" that's too much.

Unfortunately, all to many dealers and owners have gone to the "bigger".

Simply put, the bigger bars, the bigger the repair bills for correcting unnecessary damages to the trailer.

My 46 years experience with Airstreams, continues to prove those tests, to this very day, as well as the income from those damages.

Hitch manufacturers as well, promote the "bigger". Why?? More profit, and they feel less liabilty.

Not one hitch manufacturer has yet tested various bar ratings and other manufacturers products, to any degree. I have done that though to a small degree, but enough to more than demonstrate the differences.

I also wrote an article, called "The hitch torsion bar story", that clearly demonstrates the differences in the bend factor of a few hitch bars.

Perhaps someday, someone may take the time and money, to further the tests that I conducted.

Andy
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Old 11-28-2012, 11:32 AM   #53
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After looking at pics I posted earlier, I realized a description should have been included. My post # 17 may be far enough back that viewers won't know what these are. First pic is of the hair pin in the extra hole drilled in the "L" pin that lessens binding. Pic #2 is the Tek screws in the A-frame to prevent clamps for the brackets from working their way rearward. The last two are pics of the inside-of-frame straps made into channel iron to stiffen them so they won't bend when tightened.
Dan
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Old 11-28-2012, 11:50 AM   #54
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Thank you again, Andy.
It was your empirical testing that led to my bar "reduction" project!
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Old 11-29-2012, 12:33 AM   #55
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mefly2,

Can you post a pic...or a link to your old posts? Thanks
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Old 11-29-2012, 01:59 AM   #56
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Quote:
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mefly2,

Can you post a pic...or a link to your old posts? Thanks
Will this help you?

The Hitch Torsion Bar Story

Andy
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