Broken TNT Track Bar bolt

[AZ XJ]

Well, bolt has been replaced with a 3/8x16x3.5" grade 8 Hex bolt from Lowes. It fits perfectly, but for some reason I'm feeling like I just installed a weaker bolt.
Upon further investigation, the bolt that was in there is indeed a grade 12.9 bolt. Lowes had socket head cap bolts, but they were only grade 8, and the longest they had was 3". Should I look for a bolt that is equivalent to what was initially in there, or will the grade 8 hex bolt suffice?

 

[ehall]

do you have a pic of the failed bolt?

 

[Begster]

Well, bolt has been replaced with a 3/8x16x3.5" grade 8 Hex bolt from Lowes. It fits perfectly, but for some reason I'm feeling like I just installed a weaker bolt.
Upon further investigation, the bolt that was in there is indeed a grade 12.9 bolt. Lowes had socket head cap bolts, but they were only grade 8, and the longest they had was 3". Should I look for a bolt that is equivalent to what was initially in there, or will the grade 8 hex bolt suffice?

Metric grade 12.9 is equivalent to a standard Grade 8 bolt.
The numbers are what are fooling you, because 12.9 is numerically higher than 8. But, they only have different ratings because one is standard (inches) and one is metric.

Which brings me to my next thing. If the trackbar came with a metric bolt, it should be replaced with a metric bolt, because metric and standard bolts are not the same size.

 

[amadeus3]

Well I would call TNT and make sure you had the right size bolt to begin with. Maybe they sent you the wrong size bol to begin with, probably not but there has to be some explanation for why that bolt broke.

 

[AZ XJ]

do you have a pic of the failed bolt?

I'll try to get one tomorrow, and post it up.

Metric grade 12.9 is equivalent to a standard Grade 8 bolt.
The numbers are what are fooling you, because 12.9 is numerically higher than 8. But, they only have different ratings because one is standard (inches) and one is metric.

Which brings me to my next thing. If the trackbar came with a metric bolt, it should be replaced with a metric bolt, because metric and standard bolts are not the same size.

Okay, I understand. That makes sense to me. I'm gonna contact TNT because, it then appears that the bolt that came with the kit is metric, however the bolt that I just put in, fits very slightly more snug than the bolt that was removed. The thought of the bolt failing again is unsettling, because I could find myself in a much more precarious position next time.