Just about lost our toad

[Mike_Harriet]

We use hitch pins on the tow, to facilitate quick release in case of car fire. Want to pull away quickly if there is one, but we do have one other safety precaution. Using a bungee cord hooked between the pin handles. Stretch it tightly left to right in case lock pin comes out. Considering a similar method to make blue ox tow system Quick release, but only when traveling. Keep lock (anti-theft) when car not hooked up.

[oatmeal]

Originally Posted by Winemaker2

I had a lock on my last MH and ended up having to cut it off after some corrosion prevented key operation.

Same here. Found a key and thought, "What is this?" and finally tracked it down to the tow bar connection to the motorhome. It's going to take a torch to get that thing off.

I can't remember why we put the lock on it. We bought the tow assembly from someone else, and think it came with the lock, and just used it.

[tuffr2]

Towing a toad seems way too complicated. Lots of little pieces.

[hohenwald48]

Originally Posted by RVPioneer

Grade 6 & 7 don't exist. Apparently they skipped over those just as there is no WD-39.

True for a steel bolt. SS shear strength is between a grade 5 and grade 8 steel bolt so most folks just call it a grade 6/7. There are charts if you want know the exact shear strengths.

And actually, there was a WD-39. It was the "Water Displacement" formula they tried just before they came up with the 40th formula.

https://www.wd40company.com/who-we-are/our-history/

[hohenwald48]

Originally Posted by RVPioneer

Graded bolts are rated for tensile strength as this is their designed function. Shear strength is generally considered to be 60% of tensile strength, so a grade 5 or 8 bolt will have more shear strength than a grade 2 "butter bolt". A pin designed and rated for shear strength would be a more appropriate component for such an application.

So, are you saying a Grade 5 bolt is not strong enough? Or are you just explaining the bolt grading system to us?

[RVPioneer]

Originally Posted by hohenwald48

So, are you saying a Grade 5 bolt is not strong enough?
Nope. Never said that. I said a Grade 5 or 8 for that matter is not designed for use as a hitch pin.
Or are you just explaining the bolt grading system to us?

Don't really see a need to explain the grading system. Just why it's the wrong fastener for the job.

[RVPioneer]

Originally Posted by hohenwald48

True for a steel bolt. SS shear strength is between a grade 5 and grade 8 steel bolt so most folks just call it a grade 6/7. There are charts if you want know the exact shear strengths.

And actually, there was a WD-39. It was the "Water Displacement" formula they tried just before they came up with the 40th formula.

https://www.wd40company.com/who-we-are/our-history/

Is there a Grade 6 or 7 on those charts?
Let me know if you come across a can of WD-39.

[RVPioneer]

Originally Posted by tuffr2

Towing a toad seems way too complicated. Lots of little pieces.

It really quite easy when done correctly. And we don't have to drive a dually everywhere once we land.

[RVPioneer]

Originally Posted by oatmeal

Same here. Found a key and thought, "What is this?" and finally tracked it down to the tow bar connection to the motorhome. It's going to take a torch to get that thing off.

I can't remember why we put the lock on it. We bought the tow assembly from someone else, and think it came with the lock, and just used it.

Periodic maintenance will prevent these problems.

[tuffr2]

You mean you do not get to drive a safe dually if you get sonewhere.

[hohenwald48]

Originally Posted by RVPioneer

Is there a Grade 6 or 7 on those charts?
Let me know if you come across a can of WD-39.

Of course there is no Grade 6 or 7 on those charts. I guess you just didn't pay any attention to the part where I said "so most folks just call it a grade 6/7". And I guess you missed the part where I said "there was (didn't say is) a WD-39". You gotta' read all the words.

[Winemaker2]

RVPioneer
At the risk of I'll provide one more post - I don't see any reference info or data to support your statements only opinions - you are certainly welcome to your opinions but I'd welcome some facts to back them up.

Originally Posted by RVPioneer

Hitch pins are rated for GVW, not shear strength. A 10K rating would match up with the rating for most of our hitches. Some 5/8" pins are rated at 18-31K.
True - but that's the same range as the Gr 5 & 8 Bolts in shear - addn'l info below

A hardened bolt or pin can cause the hole in the hitch and receiver to "egg out", creating a situation the would require replacing both components.
Same with a hitch pin if there is movement - they are in fact the same except for the retainer being threads / nut vs a hole and retainer pin

Originally Posted by RVPioneer

Don't really see a need to explain the grading system. Just why it's the wrong fastener for the job.
So rather than an opinion explain why a Gr 5 bolt is any different than a Gr 5 hitch pin (so long as the shear plane is through the bolt shank and NOT the threads)

Originally Posted by RVPioneer

Is there a Grade 6 or 7 on those charts?
Let me know if you come across a can of WD-39.
There is in fact a Gr 7 in the charts - never have seen one but apparently they do exist - see below

So - My contention / opinion is...

1. To say "Graded bolts are rated for tensile strength as this is their designed function." is false - Bolts are used in in shear in structural applications routinely
   
   
2. Bolts are rated for BOTH tension and Shear (in fact many tables show both single and double shear values) and Double shear is actually stronger then the tension values (120%) The only case where bolts are lower is where the double shear plane is through the threaded portion and the effective cross sectional area is reduced thus reducing the strength.
   
3. Rated Hitch pins are rated using the same SAE Standards as Bolts
   
   
4. Gr 5 Bolt or Hitch Pin provide the same strength (and wear characteristics) so long as the bolt threads are outboard of the receiver (shear plane)
   
   
5. The (double) shear strength tables for both show same / similar capacities
   
   
6. Best practice when using a Gr 5 or 8 bolt in a receiver would be to double nut it to prevent loosening (I guess I see a NyLock nut providing a similar safety factor)

[RVPioneer]

Winemaker2,

You are entitled to your opinion as well. And you are free to use any means you feel are appropriate to tow with your RV.

As recreational vehicle operators we are exempt from most of the regulations imposed on commercial drivers yet we are driving 30,000 plus pound vehicles while towing 7000 pound SUV's or trailers. All this with no specialized training required. I've spent a career in an industry and owned equipment that was subject to inspections every 90 days in addition to inspections at commercial scales. The smallest infraction will result in the equipment being taken out of service on the spot and frozen until it has been corrected. Therefore I choose to use equipment that was designed for it's intended purpose.

I do this for the safety of myself and my vehicles as well as all the other drivers on the road.

[Unplanned Tourist]

Whatever works for the towee and is safe, works for me.

Happy Glamping.