Street bumper mounts

[DanEC]

Originally Posted by mikeinatlanta

The above statement is 100% untrue and nothing but an internet myth, however, even an ungraded bolt will be stronger than your bumpers so I would worry more about fit than bolt grade. Mcmaster has a wide range of sleeve materials from aluminum to stainless and in a range of wall thicknesses to suit the look you want.

In the case of my bumpers, they are made from 18 gage cold rolled and the mounts are 18 gage hot rolled. The whole mess can be moved by hand and even an aluminum bolt is stronger than the bumper and mount.

I agree that an ungraded bolt (Home Depot all-tread) should be sufficient for this application. But since it was suggested that he go to Mcmaster for some "high tensile strength" rod - I felt there was no need to go overboard on high strength - grade 8 material. Yes, the issues of Grade 8 brittleness are primarily related to continuously stressed applications where work hardening can lead to brittleness versus where a Grade 5 will yield and deform instead. I'll give you that it isn't an issue with a bumper bolt that isn't exposed to cyclic loading.