Chromoly traction bars?!

[c5fourj]

Has anyone out there tried using chromoly for set of traction bars vs the basic DOM tubing? I have a buddy wanting me to try a set of 72", 1 7/8 bars on my truck. Didn't know if they could handle the same tensile strength as all of the other 2 in DOM trac bars.

 

[Bdsankey]

Has anyone out there tried using chromoly for set of traction bars vs the basic DOM tubing? I have a buddy wanting me to try a set of 72", 1 7/8 bars on my truck. Didn't know if they could handle the same tensile strength as all of the other 2 in DOM trac bars.

Should be fine depending on wall thickness. I built my traction bars out of 2" ODx0.25" wall A513 DOM. My bars have taken a beating without any issues. 4130 chromoly has a yield strength of ~63ksi whereas A513 DOM is ~75ksi. For example, people have used schedule sized pipe which is usually ~30ksi yield.

 

[c5fourj]

Are those all yeild strengths for 2" bars?

 

[Bdsankey]

Are those all yeild strengths for 2" bars?

Yield strength is a material property, not a result of size. You would have to use Euler's buckling formula to determine what the maximum load the member/beam (bar) can support is.



What is the wall thickness on the bars your friend wants you to run?

 

[Chevy1925]

i built many chromoly traction bars back in the day and still run them to this day on my truck. you can run a much thinner wall than the typical 1018 hrew steel or even DOM due to its strength. that 513 steel is about on the same playing field as chromoly but is much more likely to crack/break than the chromoly due to its tensile strength. part of the reason racing bodys wont let you consider it the same as chromoly.

i would much rather run chromoly over typical hrew or cold drawn. never had one fail even under sled pulling conditions.

 

[c5fourj]

Never asked on the wall thickness, but good to know James. Thanks for both of your imputs.