New to the forum and I have questions about the Pull Rite travel trailer hitches I have a complete hitch set up that I got for $75 and am wondering about some of the forces involved. I am by no means an engineer and don`t have the math skills to figure this one out. I have included a crude diagram of all the distances and forces that I know. What I would like to know is the downward force at the pin by the diff and also the forces on the bearing rollers? any help would be appreciatedThanksMark[img][/img]

OK pic dis not seem to come up so i'll try again.

My friend had one when he towed a race car with his Ford and also had a Lance camper in the bed at times. The torsion bars also hold the trailer straight to the hitch and the pivot is just behind the rear axles.I can't help you with the forces. Not sure if anyone but pullrite can answer that.

Great hitch and you got a super price! Don't worry about force on rollers if they are in good shape. I had a full size Bronco with the Pull Rite back in the late '80s, pulled a 26' StarCraft TT from FL to AK 18K never a problem. You will (with practice) get into sites easier and amaze others because they really work. No sway at all even on my short wheel base because the pivot point is about at the rear axle, just like a fifth wheel. You will answer lots of questions from people about your funny hitch. Enjoy...BTW they were well over a grand in the late '80's. :) :)

You got yourself a steal and what is considered by many to be the best hitch money can buy. If our member Ron Gratz comes by, I am sure he can give you the numbers you are looking for. In the meantime, you might want to give a good look at this thread by him that is stuck at the top of the forum. Some of the questions you asked may be answered in that threads first post. Barney

Bendder wrote:---What I would like to know is the downward force at the pin by the diff and also the forces on the bearing rollers? any help would be appreciatedMark, welcome to Open Roads Forum.You can get a good estimate of the downward force at the pin by using the following leverage equation:Force * (61.5" + D) = TW * D or Force = TW * D / (61.5 + D)where 61.5" = distance from pin to ball per your diagram,D = distance, in inches, from ball to midpoint between TT's axles, andTW = tongue weight.The above equation assumes there is no significant vertical force exerted on the roller bearings.It is my understanding that the WD bars should be adjusted to minimize this force.For your information, this thread contains a wide-ranging discussion of the PullRite hitch (and a lot of other stuff).This web page by ORF member, Steve Rankin, shows his installation process.BTW, you did a great job on the PullRite diagram -- except the downward force on the ball (which you show as 1000#) is equal to the TW plus the downward pull exerted by the two lift chains minus the amount of load transferred to the TT's axles.For your example the downward force on the ball might be approximately 1000+2000-200 = 2800#. (The 200# depends on "D" in the above equation.)The upward force exerted on the hitch head via the front ends of the WD bars would be 2000#.The net force exerted on the hitch head, and transmitted to the pin, would be about 800#, if we ignore the weight of the drawbar which extends from hitch head to the pivot pin.Ron

PullRite TT hitch questions Update Installed Pic's

Bendder
Explorer
Oct 15, 2014
So I have a good run with the new hitch installed and can attest to it being very smooth. I experienced absolutly no sway from the trailer whether I was passing other vehicles or them passing me. The only time I felt anything was when a SEMI got up to the nose of the truck and pushed me just a bit (nothing to do with the hitch, normal) I will need to get used to where the limit stop is on the rail for max turning but for now my 12yr old hops out and tells me how much turn I have left. It was nice to be able to stop for a shopping stop on the way to the CG and be able to open the tailgate now that the TT is a bit further back. Also nice was getting home and being able to fit the whole rig in the drivway with out the need to unhitch. As you can see from the pics I was able to just get into the length of my driveway and I was at max turn 70*

Overall very happy. Truck rides much smoother, no sway, easy to hich and unhitch, better access to the bed of the truck.

Mark
Moderator edit to re-size pictures to forum limit of 640px maximum width.
jerem0621
Explorer II
Oct 15, 2014
That's a slick set up! Congratulations on the great find!
Bendder
Explorer
Oct 15, 2014
Yup. Very happy with the results. Might need to fine tune the WD bars at the scale to realy dial things in. Need to drop the tilt down a notch on the hitch head. Looking forward to a trip to the scales to see how much weight was realy removed from the truck
Mvander
Explorer
Oct 15, 2014
Great setup. I really like the design of the pull right. The only down side to me is their considerable weight when used on a vehicle with lower payloads.
Bendder
Explorer
Oct 16, 2014
That's true. I weighed mine before the instal and everything weighed 164lbs. Considering the only thing I lost in weight was the spare at 73lbs i have a net gain of only 91lbs. I will be putting my spare under the trailer (truck used 95% to pull it) i will gain some of the 73lbs back but not much. Planning on putting spare just forward of axles. Biggest drawback I see is moving the spare. If i could find a large enough and skinny enough tire as a spare I will stuff it back where it goes. Only thing stopping it is the width of tire.
jerem0621
Explorer II
Oct 16, 2014
Bendder wrote:
That's true. I weighed mine before the instal and everything weighed 164lbs. Considering the only thing I lost in weight was the spare at 73lbs i have a net gain of only 91lbs. I will be putting my spare under the trailer (truck used 95% to pull it) i will gain some of the 73lbs back but not much. Planning on putting spare just forward of axles. Biggest drawback I see is moving the spare. If i could find a large enough and skinny enough tire as a spare I will stuff it back where it goes. Only thing stopping it is the width of tire.

As to the spare tire...many new vehicles are not even coming with a spare tire now. They are coming with an air pump and fix-a-flat trype stuff in them. Walmart sells a similar kit for SUV's for $30-40.00.

I haven't changed a spare tire in years and years. On the side of the road I just put a plug in the tire and air it up.

Thanks!

Jremiah

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