Are 2 zinc 3/4 bolts strong enough to hold ICC/DOT bumper/tube?

I'm driving a 579 with a bulk rack. Whatever they're called. In construction so the truck bounces around quite a bit.

Not having any issues.

 

Grade 2 is not strong enough for structural and stay away from anything stainless.

Grade 8 and most will be zinc plated. Try fastenal, tractor supply or farm fleet.

 

Tractor Supply has Grade 8. That’s where I get them.

 

Tractor supply will have them.

 

I was just @ my local TSC and they did have from 2 to 8” in stock in 3/4.

 

Let a licensed engineer here tell ya somthin' about hardware:

First of all, you mean a Zinc-plated bolt, as Zinc itself is a very weak metal. This is likely just a 'hardware grade' bolt with a zinc plating for a bit of rust prevention, as well as making it look pretty. Zinc plating comes in 'electroless zinc' (shiny), and yellow zinc (yellowish). You might also be able to find them in black anodizing. These are your cheapest choice, and also your weakest. If you drive in the northeast, this bolt will corrode in 2-3 years.

Stainless will not corrode, but is also brittle. Strength is a bit higher, though, but they will still look nice after a few winters. Will likely break in an accident, though.

Graded bolts are made of a tougher steel grade, and and are forged. Great strength, stands up to rust for literally decades, but costs the most and is kinda ugly. Still, of the bunch, this is the only one likely to survive an accident intact.