There is truth in that, but the sub does more than that. It also can be setup to control forward "sub-roll" of the hips and downward travel of the torso. If it is a proper cradle setup with good mounting, a sub can actually reduce chest loads by engaging the entire belt system more quickly, thereby reducing kinetic energy.

I dissagree. The load on the fastener is the same, albeit in a different direction. The big difference is how the load is rendered. If forward mounted, the load is not opposed by the mount and direction of the belt. That load is put into the seat base - concentrated at the pass through hole - as the forward force tries to pull the belt up.

If mounted aft, the force is directly countered by the sub belt "pulling back" in more linear opposition. This is the "pushing/pulling the rope" reference that Greg made. An astute reference indeed.

 

Here;

Let's clear up the mystery and set it straight, at least in terms of sub performance. I have just published an article I wrote on this to my website. Take this link for a discussion on how subs work.

http://www.redlinerennsport.com/CrashBiomechSub.pdf

 

So by all that can I infer that for my 25 min DE sessions, the "sit on sub" method is fine, but that for longer sessions or if I went to Club, that through the seat to some yet to be determined, almost certainly compromised unless fab & welding is involved, anchor point?

 

Nice succinct article, btw! THX!

 

Hey;

Two things. 1) If it does not bother you to wear a sub in that fashion, then go for it. It works. 2) If it does not bother you, it is likely a sign that it is not tight enough!

Test: If after tightening the lap belt as tight as possible, the lap belt rises to any significant degree when you tighten the shoulder belts, then the sub is adjusted too loose.

 

Good rules of thumb...thx.