Engineers - please chime in on this thread...

[SaddleUp]

That bolt is in a shackle, if I remember right making it a double shear...but it may have been single. Still impressive.

John

No more impressive (to me anyway) than the pin in the average hook on a winch. That's even smaller and is often subjected to an even greater pull. Great sales gimmick though.

 

[Mark]

No more impressive (to me anyway) than the pin in the average hook on a winch. That's even smaller and is often subjected to an even greater pull. Great sales gimmick though.

Those tiny pins have got to be the weak link! I have trouble trusting them.
You should see the pins on the D-rings that I upgrade to - as thick as your thumb!

 

[SaddleUp]

Those tiny pins have got to be the weak link! I have trouble trusting them.

I've never seen one fail. I've seen the hooks break before though.

 

[Mark]

I've never seen one fail.

Must be because they are mounted double shear!
I'm smarter already. ;D

 

[drader]

Anyone have pics of the safest setup. I plan on installing shoulders sometime soon. Any link, pics, or advise is appreciated.

 

[SaddleUp]

Anyone have pics of the safest setup. I plan on installing shoulders sometime soon. Any link, pics, or advise is appreciated.

This probably isn't what your looking for but it is what I consider as pretty safe. 5 point belts tied directly to the roll cage at all 5 points. Additionally the seats are connected directly to the cage as well. Connected in this manner the entire roll cage can be ripped loose from the body and the occupants will all hopefully stay inside the cage where it will be the safest. The rear seat doesn't have quite as much protection. It only has 3 point belts. The seat and belts for it though are also tied directly to the cage.

 

[4x4x289]

More info.

I found this pic at http://www.stockcarracing.com/howto/scrp_0603_racing_seatbelt_installation/

The direction of force for both of these applications is assumed UP towards the top of the picture. For the application on the right, the bracket acts as a crowbar against the bolt head causing increased stress on the right side of the bolt shank and also on the bracket. The increased stress on the bolt and bracket is caused by moment. This senerio is simular to attempting to pop off a cap of a beer bottle. Will it fail? I don't know, -it depends on the strength of your hardware and the pull. There are no Yes/No answers. The only thing I am willing to say is that the BOLT and BRACKET on the left are "less likely" to fail "only if" the BOLTS and BRACKETS are equal on both sides, and "only if" the force which causes the failure is up. This does NOT mean failure will occur, or that your steel tab(s), welds, or base metal won’t fail first. Your total system strength is only as strong as your weakest link. Your weakest link, in fact, might be considered your torso as stated earlier. If, in fact, the bolt or bracket fails on the right, to help visualize it, the two likely failure scenarios are like actually removing a bear bottle cap, or pulling a plastic six pack ring off a single beer can.

Yes the application on the right is commonly used by industry, HOWEVER, the application on the right for industry is generally for forces going to the RIGHT, ie., with bolt mainly in shear (single shear BTW, with some moment), and remember that industry does test it. The bolt on the left sees double shear with force going up.

I value the opinions of a people with experience. To engineer is human. A non-engineer can still build something based on knowledge of prior success and failur, comparisons, i.e, experience. When in doubt, an item can still be tested. An engineer is not god. An engineer can still misguide, miscalculate, misapply, or fail to calculate/evaluate a failure that actually occurs.

 

[SaddleUp]

More info.

I found this pic at http://www.stockcarracing.com/howto/scrp_0603_racing_seatbelt_installation/

The direction of force for both of these applications is assumed UP towards the top of the picture. For the application on the right, the bracket acts as a crowbar against the bolt head causing increased stress on the right side of the bolt shank and also on the bracket. The increased stress on the bolt and bracket is caused by moment. This senerio is simular to attempting to pop off a cap of a beer bottle. Will it fail? I don't know, -it depends on the strength of your hardware and the pull. There are no Yes/No answers. The only thing I am willing to say is that the BOLT and BRACKET on the left are "less likely" to fail "only if" the BOLTS and BRACKETS are equal on both sides, and "only if" the force which causes the failure is up. This does NOT mean failure will occur, or that your steel tab(s), welds, or base metal won’t fail first. Your total system strength is only as strong as your weakest link. Your weakest link, in fact, might be considered your torso as stated earlier. If, in fact, the bolt or bracket fails on the right, to help visualize it, the two likely failure scenarios are like actually removing a bear bottle cap, or pulling a plastic six pack ring off a single beer can.

Yes the application on the right is commonly used by industry, HOWEVER, the application on the right for industry is generally for forces going to the RIGHT, ie., with bolt mainly in shear (single shear BTW, with some moment), and remember that industry does test it. The bolt on the left sees double shear with force going up.

I value the opinions of a people with experience. To engineer is human. A non-engineer can still build something based on knowledge of prior success and failur, comparisons, i.e, experience. When in doubt, an item can still be tested. An engineer is not god. An engineer can still misguide, miscalculate, misapply, or fail to calculate/evaluate a failure that actually occurs.

Great article. Looks like I got mine set up right.