RedlineMan

Example of the status quo;



Subs mounted to tin floor with eye bolts. If you look closer you can see that the arrow points to the zenith of a large dent in the floor pan. Result; instant loose sub straps. Let me offer some statistics;

- Subs see in the neighborhood of 1500lbs force in the "average" 30-40G hit.
- With a 6-point T-bar sub like this one (Schroth Profi), the sub not only holds the lap belt low, but gives some cradle to the hips. A loose sub means degraded hip control.
- The quicker you stop hip motion, the faster the rest of the system takes up slack.
- With a very solid and snug lap/sub system, chest loads are reduced as much as 10-15%.
- With the same setup, neck tension loads can be reduced by as much as 5-10%.

I think all can see my point here.

PT

John,
Where do you mount the sub belts then?

thanks...

TheOtherEric

I don't, but I can guess. I think you're saying that we're gluing a popsicle stick to a kleenex. I don't totally disagree.

p.s. here's what Schroth's website says, I think:

"The pelvic movement combined with the shoulder belt forces will load the anti-sub straps to more than 6 kN [1,320 lb] each in a 5- or 6-point racing harness and can be intentionally higher in a F‑type model where the anti-sub straps are routed rearwards."

jester911

I am curious about this as well. I am in the process of installing roll bar, 5 point harnesses and fixed seats. I don't have a problem adding some beef in there.

What do you guys suggest?

Cory M

Drill though the floor with a holesaw and bolt them to the ground underneath the car

RickBetterley

Smart guy; that would slow you down a bit, wouldn't it?

Sean F

Well I hope you're going to fix that piece of sh*t. What kind of a jerk would do that? Man, some people really have no clue what they're doing.

I'm glad I took the rollbar out before you saw it

P.S. I thought this was in accordance with Schroth instructions.

jester911

Well I can see getting a straight answer around here might be a bit of a challenge

No problem.

Lemming

I have faith that John will post his answer as soon as he is done correcting the problem and has the next series of photos.

RedlineMan

Hey;

I didn't do this to say that everyone who has a sub mounted like this is an idiot. It is the convention. Most times you see racing rules or manufacturer specs, they talk about this method. It is common wisdom. Also do remember that the Earth was at one time known for a fact to be flat.

I did it for no other reason than to make people think. When you DO think about it, you should see that a sub mounted in this fashion does not stand much of a chance of actually staying in its original position. It took about 4-5 shots from a 4lb hammer to bonk the floor back down. Not much force there.

Truth be told, the sub is generally the hardest belt to mount. Stay tuned...

PT

ok - I'll tie my sub-belt thru the tin to my concrete floor in the garage in the meantime as suggested then

sjanes

That's how I have my subs mounted except they are further apart, so I'm interested in your solution. When I mounted mine, I considered putting a 10"x4" steel plate under the floor and put the eyebolts through it, but I never did.

PT

You mean adding a 10"x4" steel plate to the garage floor? That sounds a little excessive

jester911

I had concerns myself about this before I saw this thread. I just started doing DE's in my car. I installed a Das roll bar and have 5 point harnesses to install. I plan on picking up some fixed buckets as well. The drivers side is a pain already because of the dme under the seat. I was contemplating using some steel plate underneath or maybe some small angle iron that would span to more structural areas.

I would be interested in what you come up with, John.

86' Carrera coupe

Sean F

I'm interested too