What is the Grade Rating on the Replacement Hex Head Bolt for Thule Goalpost

Question:

My previous bolt started showing tear, so I was wondering what grade of steel is this part? What grade is the original Thule part meant to be?

asked by: Rodolphe D

Expert Reply:

I went to our warehouse to pull this hex head bolt # 908-1240-54. This bolt will have a property class of 8.8 and is classified as a high strength steel bolt.

The point at which a bolt fails is the tensile strength, and because it is elongated (much longer than the actual width), the bolt probably failed because it was used past the yield point. As a result, causing permanent deformation and wear. The most common property classes most often used are 5.8, 8.8 and 10.9. If there isn't a number/marking on top, that will indicate a lower grade bolt with low strength. See the picture I included of the top of this bolt.

expert reply by: Chris B