Hitch Pins

[ahlkey]

I have found it hard to find how high a 5/8 hitch pin is rated at? I recently purchased a large forged ballmount rated at 20K and want to make sure that the 5/8 hitch pin is not the weak link? It would seem that if you can get a larger capacity forged ballmount that it should be possible to get a hitch pin rated for higher capacities as well. At the local supply stores the hitch pins have lower capacity rating that are less than 14K so I wonder if I will be ok? Any thoughts on where I can get a higher capacity hitch pin for use on my new forged ballmount?

 

[MikeD74T]

From a quick look at hitch manufacturor websites it seems that 5/8" pins are used for receivers up to 2-1/2" & a 3/4" pin is used for 3" receivers.
The 5/8" pin appears good to 18k lbs hitch rating.

It would also seem that you've upgraded to the 3" hitch for the 25k capacity. If you have a 3" receiver you probably want this pin Super Titan Trailer Hitch Pin and Clip for 3" Receivers Draw-Tite Hitch Accessories 58388,

Have you measured the hole in your receiver & ball mount? MikeD74T

 

[ahlkey]

Actually this is a 2" inch receiver. It is on my F650 diesel truck and is welded inside a large beam that is welded to the flatbed frame of the truck. I had a recent thread on this subject regarding if I could go to a larger forged ballmount with this setup. I even took the truck into a local hitch shop that makes construction trailers and they agreed I would be be fine with going to 20K on my truck hitch setup. However, this got me thinking that maybe my hitch pin would shear or be problem at a higher capacity.

Online the Curt 5/8 alloy steel hitch pin only lists a 12,000 GVR rating? I basically want to load my tri-axle trailer with sawlogs to around 17K to 18K maximum (trailer weighs 5,000 so load of around 13,000lbs) given the tires but want to be sure my hitch pin is at least rated for 20K or so? I did notice that the forged heated treated 5/8 "red head" type hitch pins used in farm applications have a grade 8 rating but I can't find a GVR rating on those? I also see 2 receiver inch pintle hookups at 20K but can't find any information on the pin ratings. Somewhere I thought I heard or read that 5/8 th hitch pins have a shear rating of 30,000 lbs but then why is Curt and others only listing the GVR rating at 12K or 14K? Thoughts?

 

[Diamondpilot]

I do not have the answer but I tow nearly daily upto 25k and have used the same pin since 2004 No issues and have even broken a hitch and on another occasion bent a ball mount.

Chris

 

[SPYDERLK]

Actually this is a 2" inch receiver. It is on my F650 diesel truck and is welded inside a large beam that is welded to the flatbed frame of the truck.

Somewhere I thought I heard or read that 5/8 th hitch pins have a shear rating of 30,000 lbs but then why is Curt and others only listing the GVR rating at 12K or 14K? Thoughts?

30K sounds good for single shear ... but you have 2 simultaneous shears -- the pin shears in 2 places during failure. So the actual shear force should be about 60K at failure. A safety factor of 4 in use if limited to 14K rating. That allows for the extremes that occur in a crash.
larry

 

[ahlkey]

All makes sense but I still wonder when you look at the specifications from the manufacturers why they only list them at 12,000 GVR or so???

 

[Mace Canute]

I found a rough rule of thumb on this site that says:

"As an empirical guide, shear strengths of carbon steel fasteners may be assumed to be approximately 60 percent of their specified minimum tensile strengths. For example, an SAE grade 5 hex cap screw has a specified minimum tensile strength of 120,000 psi. Therefore, for design purposes, its shear strength could be reasonably assumed to be 70,000 psi."

A link in that site leads to this site which gives tensile strength for Grade 5 and Grade 8 fasteners.

A Grade 5 5/8" fastener has a sheer strength of about 11K so double that as SPYDERLK has explained and you get 22K...3/4" Grade 5 gives you about 31.8K...5/8" Grade 8 gives you about 27.6K and 3/4" Grade 8 gives you about 39.7K

How does this relates to the strength of hitch pins you ask? I'm not sure! But I suspect a hitch pin would be very close to the equivalent of a Grade 5 bolt at least.

I don't think you have a thing to worry about as long as the pin you use is a good fit for the hole in the receiver.

 

[Skyco]

I don't think there is much to worry about shearing a 5/8 pin unless you get rear ended really hard. Then the pin is the least of your worries if the hit is that hard...
Back about 1970 I was in a Ford pickup that got rear ended so hard it sheared off all 4 bolts that held the step bumper on...don't know the size or grade of those bolts but they were pretty hefty. The truck was virtually undamaged, should have seen the car that hit me though.

 

[Diamondpilot]

One word of caution for you folks reading this. DO NOT put in a hardened pin. I have seen this done to only damage the hitch itself. I have seen the 5/8" hole egged out to better than 1" total ruining the hitch its self. I would much rather replace a $3 pin than a $150 hitch.

Chris

 

[SPYDERLK]

I found a rough rule of thumb on this site that says:

"As an empirical guide, shear strengths of carbon steel fasteners may be assumed to be approximately 60 percent of their specified minimum tensile strengths.
A Grade 5 5/8" fastener has a sheer strength of about 11K so double that as SPYDERLK has explained and you get 22K...3/4" Grade 5 gives you about 31.8K...5/8" Grade 8 gives you about 27.6K and 3/4" Grade 8 gives you about 39.7K

Mace, Could you go over your numbers? ... Using the 60% Im gettting around 21K for single shear on Gr5 -5/8. ... 0.3 sq-in right :confused2:
larry

 

[Mace Canute]

OOPS! :ashamed:You're right. I divided by 2000 instead of 1000. For some reason I was thinking of how many tons it was.

 

[schmism]

how do you people plan on generating 22,000 lbs of horizontal force on hitch pin?

 

[Skyco]

I don't think one can, unless rear ended as I mentioned...:laughing:

 

[some zilch]

even if you get hit hard enough in the rear to shear a hitch pin in 2 places, the hitch cant go anywhere, b/c the ball will hit the opening of the square tube. my guess is that if you get hit that hard, you are probably not going to be pulling the trailer home.

 

[wallace]

Guys have you ever been to the local fair when they are doing the 4wd truck pulls.........Those trucks put the pins to the ultimate test. Case you guys don't know or did realize, that sled starts out around 34,000lbs.
If you have ever seen any of the trucks hop, jump, jerk. You would have faith in the pin.
I have been around that sport for 25yrs and yet to see one hitch pin break.
I seen tons of hitches break and guys rip the receivers off but never a hitch pin break.

 

[SPYDERLK]

Guys have you ever been to the local fair when they are doing the 4wd truck pulls.........Those trucks put the pins to the ultimate test. Case you guys don't know or did realize, that sled starts out around 34,000lbs.
If you have ever seen any of the trucks hop, jump, jerk. You would have faith in the pin.
I have been around that sport for 25yrs and yet to see one hitch pin break.
I seen tons of hitches break and guys rip the receivers off but never a hitch pin break.

If you are saying that the sled presents 34K minimum resistance to being pulled and then goes up from there Id say youre in the range of bull dozer pulls. Nothing as lightweight as a pick up type truck is going to have sufficient traction to move against a 34K# resistance. Their weight would have to be in excess of 30K to have a chance of moving any distance at all.
larry

 

[Diamondpilot]

Guys have you ever been to the local fair when they are doing the 4wd truck pulls.........Those trucks put the pins to the ultimate test. Case you guys don't know or did realize, that sled starts out around 34,000lbs.
If you have ever seen any of the trucks hop, jump, jerk. You would have faith in the pin.
I have been around that sport for 25yrs and yet to see one hitch pin break.
I seen tons of hitches break and guys rip the receivers off but never a hitch pin break.

I was thinking the same thing. I can not tell you how many shrubs and stumps I have jerked on in my younger days without a single failure.

Chris

 

[Duffster]

I have seen several pins snap at truck pulls. The hopping and jerking is usually what gets them but sometimes it is in the middle of a nice smooth pull.

 

[Raspy]

I worry more about what keeps the pin in. It seems like the snap clip could easily come off and let the pin begin to walk out. I use a 5/8 bolt a lot of the time and screw on a nylock nut. The bolt is long enough that the unthreaded part is taking the load at the holes. But that's hard to change compared to a simple pin. There doesn't seem to be any foolproof and yet simple design.

 

[Skyco]

The hitch pins I use are locking ones...they have a set of 4 digit combination wheels on the end to retain the pin.
3 advantages- they can't come off and they prevent someone from easily stealing the drawbar. I also leave a receiver mounted winch on the front of my truck and it is locked the same way. Third advantage is I set my own combi and don't have to keep up with yet another key as with the common key locking pin..
Even worse I heard of a prankster once stealing the pins out of drawbars with trailers attached, then the unknowing owners went down the road and had their trailers come off the truck, with the drawbar of course firmly coupled onto the trailer.

Image below shows them- made by Trimax and a google will turn up widely priced sources for them