Curt fifth Wheel Hitches

jerem0621 wrote:

Cummins12V98 wrote:
I personally would like to know what the grade of the 4 bolts are that hold the head to the base and the two bolts that hold the base together are if I owned one and towed heavy like I do.

Our previous conversation about this led my research to find that these are grade 5 metric equivalents. Nearly PSI for PSI.

I don't have the confidence to say they are grade 8 equivelant.

Here is a chart that should help some.

Chart

Seems that the eyeball size of the bolts are around 16 mm...

The proof load of a 16 mm 8.8 bolt is 600 MPa or 87,022.62 psi

So it has more in common with a grade 5 bolt than a grade 8 it's a little stronger than a grade 5 at 85,000 psi but no where near a grade 8 bolt at 120,000 psi...

But a grade 5 is more than strong enough for this application...

Those four bolts combine for 348,088 psi strength just in the bolts.

Thanks!

Jeremish

Thanks! Being from China what guarantee do we have that the bolts are actually what they should be.

I bet that was a sad day at the Curt Plant when they let the employees know their 5er hitches will be made in China.