Yes or No? What is the popular wisdom on using washers when installing a bolt in bar/cage?

 

I'm assuming you're talking about the underside. Use the biggest thickest washers appropriate for the bolt size. Grade 10 stuff.

Warren

 

I used the thick plate that's supplied with the Autopower bar.

 

Used washers to keep the bolts/nuts from digging into the cage itself. Used washer for the nuts when bolting through the floorboards to keep the nuts from binding on the plate. All this was on the Autopower cage in my dead Civic. I also changed all the nuts that came with it from two grade 5 nuts jammed together to a nylock type grade 8. HTH

 

Are you sure changing the bolts was a good idea?

If I remember correctly (again, I could be way off base), the higher the grade, the stronger the bolt when pulled only. Its ability to resist shearing forces (as would be the case on a rollcage) is actually reduced, as the metal is more brittle.