Load Capacity: Tow Hooks

[Sweet 72]

Does anyone know what the load capacity is on the factory tow hooks from 67-72?

[jerry moss]

Originally Posted by Sweet 72

Does anyone know what the load capacity is on the factory tow hooks from 67-72?

not sure on the exact poundage is BUT it's way more than the frame would tolerate-in other words you would rip the frame apart before the hook would break.

[mike16]

I recall some one peddaling some cast iron look alike junk and selling them for outrageous money. crooked and and unsafe

[dennislbrooks]

Someone will know, but comparing to Gemplers forged steel hooks, probably above 9000 lbs per hook. I wonder why the removed thread guy did not offer cast steel instead of the cast iron, as cast steel probably also would have surpassed the frame strength.

Just wondering...

[donandal]

Originally Posted by dennislbrooks

Someone will know, but comparing to Gemplers forged steel hooks, probably above 9000 lbs per hook. I wonder why the removed thread guy did not offer cast steel instead of the cast iron, as cast steel probably also would have surpassed the frame strength.

Just wondering...

I have had castings made locally for old motorcycle and car restoration. The company that does the casting will do aluminum, bronze, and cast iron. He says he doesn't do steel, so I guess it is more involved.

I thought the thread removed guy said he destroyed his molds...
Hmm?

[Sweet 72]

The thread wasn't removed by me, you can thank the admin.

[Sweet 72]

I'm having them drop forged reproduced.
And these will rip the frame from right under your seats.

[SS Tim]

Spent about two hours looking through some GM engineering docs and manuals I have to no avail.

So using simple numbers and accepted practices for winching a rolling load I'm thinking that they need at least a 70,000lb plus load capacity. Taking into the fact the the C30 maxs at 14,000lb gvw and the accepted safety factor of 5:1 that puts us at 70K as a safe low working limit.

[dennislbrooks]

Here is a link of a guy who supposedly designed them for GM.


http://forums.trailvoy.com/showthrea...s/20968?page=1


70K sounds a little high for a 1/2 thru 1 ton but not saying you are wrong. Grade 8 bolts and frame may give before that.

Probably if you are a GVW you better hook to both hooks.

[Sweet 72]

Originally Posted by SS Tim

Spent about two hours looking through some GM engineering docs and manuals I have to no avail.

So using simple numbers and accepted practices for winching a rolling load I'm thinking that they need at least a 70,000lb plus load capacity. Taking into the fact the the C30 maxs at 14,000lb gvw and the accepted safety factor of 5:1 that puts us at 70K as a safe low working limit.

Thank you.

[Sweet 72]

Originally Posted by dennislbrooks

Here is a link of a guy who supposedly designed them for GM.


http://forums.trailvoy.com/showthrea...s/20968?page=1


70K sounds a little high for a 1/2 thru 1 ton but not saying you are wrong. Grade 8 bolts and frame may give before that.

Probably if you are a GVW you better hook to both hooks.

Thank you.

[SS Tim]

Originally Posted by dennislbrooks

Here is a link of a guy who supposedly designed them for GM.


http://forums.trailvoy.com/showthrea...s/20968?page=1


70K sounds a little high for a 1/2 thru 1 ton but not saying you are wrong. Grade 8 bolts and frame may give before that.

Probably if you are a GVW you better hook to both hooks.

Can you repost what info/quotes the page has? It wants to me to register see the page linked.

[dennislbrooks]

I don't think you have to register just arrow down to the the thread. But here is the quote.

Tow Hook Strength
I used to design tow hooks for GM trucks.

Real-life conditions, such as jerking, cold weather, random pull angles, repeated use, etc., make defining a specific load rating impossible.

GM does consider things like trailers and helicopters when designing tow hooks, so it's safe to say they will take several thousand pounds in any reasonable pulling direction.


http://forums.trailvoy.com/showthrea...s/20968?page=1

[Sweet 72]

Originally Posted by mike16

I recall some one peddaling some cast iron look alike junk and selling them for outrageous money. crooked and and unsafe

Well I don't know about cast iron being junk... I only cook with my cast iron.

[Gromit]

If it were me I would take into account (in the tow hook design) not just the capacity but also what happens to the pieces assuming the tow hook fails.

Assuming 70,000 lbs any loose fragment will be moving away from the fracture at ballistic or at least potentially fatal speeds.

I recall reading about a bulldozer trying to pull another bulldozer (that had become stuck) using a chain. One of the workers standing nearby was killed when a link parted. It is in the OSHA reports from around 1972 or so in Southern California.

[Sweet 72]

Originally Posted by dennislbrooks

Someone will know, but comparing to Gemplers forged steel hooks, probably above 9000 lbs per hook. I wonder why the removed thread guy did not offer cast steel instead of the cast iron, as cast steel probably also would have surpassed the frame strength.

Just wondering...

I don't know if it was mis understood in that original thread, but that other thread was for cast steel, not iron. Inside the thread it was posted what the specification was, "astm a148" 80/50 (80,000 tensil, 50,000 yield), which is a steel specification. But there was so much chatter that I wonder if people actually took the time to read or just jumped to assumptions.

I am looking a drop forged now, because I am still a little concerned how well cast steel would hold up in actual usage.

Still open to conversation.

[dennislbrooks]

Well, there is a pair of eom on ebay for $250 and you actually do not know for sure the abuse or non use they have taken. So I guess the pricing may determine the need. I would think you would have to produce and buy so many for them to make them --drop forged being probably the more expensive than cast steel. As I understand yes drop forged is stronger but depending on the alloy of the cast steel they get closer. Cast steel may bend easier before breaking -- but still exceed the bolts and frame and could be a better thing than an explosive break. Dunno

I would be satisfied with quality cast steel. I worked on crews that had to unstick and pull backhoes and small dozers with digger trucks and stake bodies and you need common sense on where to stand to protect yourself from a winch cable or chain or hook if something gave.

If you do not have that sense --- you may easier become a victim.

[Grumpy old man]

This whole idea of reproducing tow hooks to cash in on the price of originals is just scary at best . Who would be crazy enough to buy reproductions for anything more than $50.00 a set ? I really wonder why anyone would ? The price has risen over the rarety of originals not availability of reproduction look alikes ? Like I said before it reeks like the south end of a north bound BULL ! I say build them , test them , copy right your version , and then spend weeks marketing your reproductions ! Best over insure them on the liability side as I'm sure they would be put to the test just cause . It's all just speculation until the op ponies up his version for approval or dismissal ! In my own personal opinion . We can all wonder if they would look right or tow 10 lbs or 10,000 lbs we'll never know until their produced .
Posted via Mobile Device

[Sweet 72]

Originally Posted by Grumpy old man

This whole idea of reproducing tow hooks to cash in on the price of originals is just scary at best . Who would be crazy enough to buy reproductions for anything more than $50.00 a set ? I really wonder why anyone would ? The price has risen over the rarety of originals not availability of reproduction look alikes ? Like I said before it reeks like the south end of a north bound BULL ! I say build them , test them , copy right your version , and then spend weeks marketing your reproductions ! Best over insure them on the liability side as I'm sure they would be put to the test just cause . It's all just speculation until the op ponies up his version for approval or dismissal ! In my own personal opinion .
Posted via Mobile Device

Well Grumpy old man, like I said just a couple posts back... Jumping to assumptions. Who said anyone was "cashing in on the price of originals"? The same question can be asked why anyone would pay near $800 for a complete repro of a GMC grille, why because they are no longer in production. It's not complicated to figure out, supply and demand is still a factor. Especially when you are looking for 40+ year old parts. I find it amusing that this causes so much assumption chatter and negative responses when dealing with tow hooks, but no chatter or negatively when it comes to repro fenders, grills, bumpers and so on.
One last thing on your thought about why someone would pay more than $50 a set... For the same reason you pay $12 for a Big Mac (at least that's what it was 10 years ago, most likely more now) value meal in Waikiki, Hawaii McDonalds verses $6 in your local McDonalds, supply and demand. And hey, the beautiful thing about America, no one is forcing you to pay $12, or even $6 for a $1 (production cost) meal, you can still choose to eat somewhere else.

[El Dorado Jim]

I like the idea of reproduction tow hooks as long as they are strong, I wasn't for them if they are for looks only...good luck and depending on price I may want a set for my 72 K20

[Sweet 72]

Originally Posted by El Dorado Jim

I like the idea of reproduction tow hooks as long as they are strong, I wasn't for them if they are for looks only...good luck and depending on price I may want a set for my 72 K20

Yeah I understand that. Believe me I wasn't for them being for looks either. The main reason for that statement was because some people are only out there to sue someone.

Thanks

[donandal]

Originally Posted by Sweet 72

I find it amusing that this causes so much assumption chatter and negative responses when dealing with tow hooks, but no chatter or negatively when it comes to repro fenders, grills, bumpers and so on.

Seriously?
you are not able to see the difference?

I'll help out then, here is a clue;

if a fender, grill, bumper, etc. fails in some way, it is doubtful that that would cause personal injury....

[Sweet 72]

Originally Posted by donandal

Seriously?
you are not able to see the difference?

I'll help out then, here is a clue;

if a fender, grill, bumper, etc. fails in some way, it is doubtful that that would cause personal injury....

Thanks for the clue donandal. And yes, grills, fenders and bumpers also come into play with safety and as potential results in injury. Why is it that there are minimum requirements put into place for those parts? Safety. That's why if I have a choice to buy and install on my vehicle I'm sticking with original fenders, bumpers and grills. I like the extra protection up front, verses low grade, paper thin sheet metal. But like I said earlier, that's my choice to buy it or not buy it.


You are going to me more likely to get hurt or killed by a chain or strap breaking than one of these hooks, unless of course the bolts are doing what they are designed to do first, which is break/shear off.

[donandal]

Originally Posted by Sweet 72

Thanks for the clue donandal. And yes, grills, fenders and bumpers also come into play with safety and as potential results in injury. Why is it that there are minimum requirements put into place for those parts? Safety. That's why if I have a choice to buy and install on my vehicle I'm sticking with original fenders, bumpers and grills. I like the extra protection up front, verses low grade, paper thin sheet metal. But like I said earlier, that's my choice to buy it or not buy it.


You are going to me more likely to get hurt or killed by a chain or strap breaking than one of these hooks, unless of course the bolts are doing what they are designed to do first, which is break/shear off.

It is also doubtful a fender would fail in normal use.
Maybe it would do a little worse in an accident. Maybe...

What's normal use for a tow hook?

[trac209]

Originally Posted by donandal

It is also doubtful a fender would fail in normal use.
Maybe it would do a little worse in an accident. Maybe...

What's normal use for a tow hook?

A tow strap can exert tremendous stress On a hook especially if being yanked from a stuck position. I have personally seen idiots using hitch balls and have them snap off and go flying threw windshields and body panels like butter. A tow hook should be able to handle extreme stress and I'd rather have a non production looking hook that's meant for it than a exact copy not built for use. Most if not all tow hooks are forged Steel and not cast. Forged steel will bend and at least take some energy out of the failure. Cast will snap and become a projectile that could easily kill a person