Dual cam VS Equalizer...I have both

chipster wrote:


Dual cam, uses the cam method to stop sway by applying more force when the trailer tries to push the bars out of the locked in cam position. Only problem I see is this cam fitment is very very poor. Look at your wear marks on the bars and the cams themselves and you will be lucky if more than a third of the surface area has any wear marks. Thus not providing near as much friction or metal on metal area the equalizer does. Also the trunion style bars have so much play in them at the connection point on the head. Sure under weight will they move not likely but they can where the equalizer has no play thus to me providing an overall better hook up.

My tongue weight is 1650# so I am inclined to keep using the Dual cam but if I had the 1400# setup for the Equalizer I think I would go that route.

Plus the Equalizer is so much easier to set up, trying to get the cams seated 100% takes some time, and also if the TV and Trailer and not loaded exactly every-time it could change the geometry of cam position not seating 100%. Equalizer flat surface, no worries.

Hi chipster,

I just want to try and help you understand one of your thought processes is not correct. It "appears" you are saying that the amount of surface area of DC contact makes the Reese less effective than the Equal-I-zer because the EQ has more surface area contact. Did I under stand this correct?

If so, that is not a correct thought process. Technically the amount of surface area in contact does not enter into the equation of how much force it takes to break free a friction holding system. I know this sounds strange, but it is one of those Laws of Friction.

Quoting Irvnig Levinson in his 1971 Text Book, Statics and Strength of Materials page 114 has these 3 points about the Laws of Friction:

Levinson wrote:
These laws state that when one solid body slides over another, the frictional force is:
1. Proportional to the pressure force between the bodies,
2. Independent of the area of contact, and
3. Independent of sliding velocity.

Using the formula below which states.

The max Force required to start an object moving (F) = Force normal (N) or the perpendicular weight of an object acting on a surface X the Coefficient of Friction (f)

F = N X f

See here:
Friction and coefficients

Surface area does not enter the equation. To increase holding power of WD bar from sliding, you either create more force acting on the bar or you change the coefficient of friction between the 2 objects.

Think of it this way. Put a cardboard box which measures 12" x 12" (1 sq foot)on your concrete drive way and put 10# of weight in it and then push or pull it. The force to break free the static friction and make it start sliding will not change if you have a box 1 sq ft. of area or 3 square feet of area. If you increase the weight in the box, then the force to start it sliding goes up proportional to the increase in weight.

Both hitches are very good and very close in effectiveness. Neither will fix a problem of sway in your TV & Camper combo by changing hitch brands. The problem is the elsewhere then the "brand" of hitch if you have a problem.

Both hitches have pros and cons due to the way they are built. I myself prefer the Reese trunnion bar DC. I will not buy the round bar Reese due with the DC due to the lack of hitch head tilt adjustment.

As far as DC wear, see my cams with 24K miles on them, notice the date.




Here are the 1,200# bars that worked with them


I am now a little over 50K miles on the same cams with 1,700# bars and a TW of 1,500 to 1,600# pending loading. The wear on the cams is not a lot more then what you see in those pics. I mark the WD bars left and right and always put them on the same side. If not, you will start a new wear pattern over and over again.

When the cams are brand new, metal dust will form quick as the high spots on the WD bars make their mark in the DC. It tames down in ~ 1K to 2K miles and then wears less as the contact patch increases. Due to my high TW, I do use a real light coat of vase-o-line on the cams. While yes there is a very slight loss of holding power, my rig is stable with no sway control and I do not notice any loss of holding power. But I do notice less noise and wear.

Good luck and hope this helps

John

PS. When the DC is set correct and you are talking TW's of 1,200# and up, changing TW loads of ~ 100 to 200# will not affect DC setting. Set it correctly, keep the WD bars on the same side and you are all set unless you change 200# or so plus TW change.