I’ll show you some bolt info
@Railwelder93 ! Take this!
No - I am not smart enough to figure this out. I found it on another forum and figure someone will double check these calcs. The winch bolts are 8.8 with the X-Bull winch, which appear to be just fine for the application given there are 4 bolts total.
Here’s the scoop:
Most winches are mounted feet forward so the bolts aren't under much strain, particularly in a straight pull. If you've mounted feet down the bolts are in shear (e.g. the plate wants to cut them off). Feet forward puts the mount into compression, which isn't straining the bolts beyond the off axis load.
Generally pascal is a measure of pressure, which is force per area. One pascal is by definition one newton per square meter, e.g. 1 Pa = 1 N / m^2. The imperial unit that is similar is lbs per square inch, e.g. psi.
What this means to a fastener is you find its area and multiply that by its psi or pascal rating. Metric bolts give you their ratings directly, 8.8 meaning tensile strength<dot>yield strength. IOW, an 8.8 means 800 MPa and 80% of tensile, e.g. 640 MPa is it's rating. A 10.9 is 1000 MPa and 90%, e.g. 900 MPa.
If you convert 640MPa to psi you'll find that to be 92,824 psi, which is as noted basically the same as an SAE grade 5.
Next you find bolt area, which is just geometry. A 10mm bolt has radius of 5mm or 0.005 meters and area = pi * r^2, e.g. it's 7.85 x 10-5 m^2.
So a 10mm 8.8 bolt will handle 7.85x10^-5 m^2 * 640 x 10^6 N / m^2 = 50,240 N or 50.240 kN.
Newtons are measure of force, which can be converted to pounds-force by dividing by 4.448, e.g. that bolt can handle 11,294 lbf. Bolts are rated in tension, so if you're using them in shear you have derate them to 60% usually. That means in shear a 10mm 8.8 will take ~6,777 lbf working.