rob20rx7

iTrader: (1)

I just got the 5 Point harness i ordered. I have already made the bar across the back for the 2 sholder pieces but where is the best place to bolt the side straps and the one down the middle. Do i replace the factory seatbelt bolt with the screw the belts bring and also replace the part where the factory seatbelt buckles on the inside with the same?

John Magnuson

Yes, use the factory mounting positions for the side belt. I used eye bolts there (available at any racing store) and just clip my 5 point in and out as needed for events.

For the submarine belt I drilled a hole in the floor pan under the seat and put an eye both through with a VERY large size washer on the outside. This is probably not the best set up but it passed tech.

rotoboy661

just get a hraness bar from rotaryextreme.com

or wrap ur beltz on the rear strut bar

zullo

No! Nowhere near strong enough. You'd be as well off duct-taping them to the back of the seat. Don't try it; I'm only joking

John Magnuson

Yeah the rear strut tower brace isn't the best attachment point. If you're using that make sure you use your stock 3 point seatbelt IN ADDITION.

DamonB

The Rotary Extreme bar uses the stock end pieces from the stock strut tower brace and this is NOT how you want your harness attached to the car if you want your harness to actually function. Consider the Rotary Extreme harness bar for show only.

If you really have need for a harness locate an M2 harness bar, install a cage or remove the divider and attach the belts to the trunk floor.

Pic of the RE bar. The bar itself is plenty stout but attaching it to the flimsy stock brackets is not safe.

Mahjik

iTrader: (1)

For reference, here's the M2 ends:

http://mahjik.homestead.com/files/FD...e/MVC-005F.JPG

clayne

I had no idea the RE bar used the stock mounting brackets. That's pretty much negates it's use as a harness bar. What's up with that Chuck?

DamonB

I specifically discussed this with Chuck some time ago and his opinion was that the stock parts were more than adequate. I pointed out to him the flimsy tabs of metal on the stock brackets that support his harness bar and he again insisted they were more than adequate. I strongly disagree. To Chuck's credit the website does state that the bar mounts with the stock brackets.

rob20rx7

iTrader: (1)

where can i get those M2 end Parts?

macdaddy

I won't get into the argument about the shoulder strap mounting location. I'll assume from your mods that you're not talking about autox. If you have reached the level in road racing (or HPDEs) or the 1/4 where you're putting in harnesses, you should at least have a roll bar. If you have a roll bar, you either have or can weld in a harness bar as part of it. That's where the shoulder straps go.

An alternative to drilling a hole in the floor for the sub strap on the 5 pts is to use a 6 pt harness. If you do that, you can mount the two ends of the sub strap to the same place as the lap belts. You sit on those straps and pull them up between your legs to the lock. You don't have to cut your seat (or have a race seat with a hole there) to bring the sub strap up like you really should do with a 5-pt. As folks mentioned above, I just replaced the stock seat belt bolts with eye bolts and clip my lap and sub straps in. It's a little tight to get both snaps on one eye (actually not hard to get them on, but harder to get them off), but definately doable, and you can still use your 3-pt belts on the street. It meets SCCA tech for Solo I. Just one more way to skin a cat. If you do use the 5 pt, make sure you have an adequately beefy backing plate for that bolt - don't just use washers.

adam c

iTrader: (2)

If the stock rear stut bar isn't strong enough, it would be really easy to have one made. Any decent welder could make one with very little trouble.

rob20rx7

iTrader: (1)

i was gonna have a rear stut bar machined out of 1.5 x 1.5 inch solid aluminum. then just drill the holes for the shoulder straps to bolt to. i dont have a roll bar yet but do plan on having one by march then i can mount the shoulder straps on there.

clayne

1.5" x 1.5" x 36" 6061 bar (52$):

Part Number 9008K47
$52.05 Each
Shape
Sheets and Bars

Sheets and Bars Type
Plain

Plain Sheet Type
Square Bar

Thickness
1.5"

Thickness Tolerance
±.014"

Length
36"

Length Tolerance
±1"

Width
1-1/2"

Width Tolerance
±.014"

Material
Alloy 6061 Aluminum (Multipurpose)

Finish/Coating
Unpolished (Mill)

Tolerance
Standard

System of Measurement
Inch

Material Certification
Without Material Certification

Temper
T6511

Hardness
95 Brinell

Yield Strength
35,000 psi

Specifications Met
ASTM B221

Flatness Tolerance
.006" per inch of width

--

1.5" x 1.5" x 36" 2024 bar (97$):

Part Number 86895K26
$97.35 Each
Shape
Sheets and Bars

Sheets and Bars Type
Plain

Plain Sheet Type
Rectangular Bar

Thickness
1.5"

Thickness Tolerance
±.003"

Length
36"

Length Tolerance
±1"

Width
1-1/2"

Width Tolerance
±.003"

Material
Alloy 2024 Aluminum (Extra-Strength Aircraft-Grade)

Finish/Coating
Unpolished (Mill)

Tolerance
Standard

System of Measurement
Inch

Material Certification
Without Material Certification

Temper
T351

Hardness
120 Brinell

Yield Strength
45,000 psi

Straightness Tolerance
.050" per foot

Specifications Met
ASTM B211


Both from mcmaster.com.

But I think you'd probably be better off with some oversized tubing or something anyways.

clayne

I guess the 275$ price tag Chuck has on his "6061 CNC machined anodized black bar" has a 220$ difference from the same bar stock you buy at McMaster because of that "CNC" machining and hefty price anodizing (like it's needed). Not to mention you know how much labor it is to drill and tap holes (give me a break).

Regardless you still have to come up with a better bracket to the strut towers with both options.

macdaddy

rob20rx7: if you're going with a harness bar that mounts to the strut towers without being part of a roll bar (against good advice) then at least don't weaken it by drilling holes in it. Just loop the shoulder harnesses around the bar, rather that looping them around a bracket that you would bolt to the bar.

artowar

iTrader: (1)

If using the lap belt mounting points is an acceptable alternative for the sub belt, what is it an alternative to? In other words, where are the "standard" 6-point sub belt termination points?

macdaddy

The function of the sub strap (antisubmarine belt) is to keep the lap belt from riding up above your pelvic brim - i.e. to keep you from sliding down underneath the belt. The bones of your pelvis are fairly strong - and can resist much greater impact. If the lap belt is not over your pelvis but over your abdomen when you undergo sudden deceleration, the lap belt can rupture your bowel, abdominal aorta, spleen, liver, kidneys, and all those other nice soft parts you'd like to keep.

With a 5-point belt, the end should be mounted almost directly beneath the harness latch. If you have a racing seat with a hole in it for the sub strap, that's fairly easy to do in most cars. If for some reason, you can't put a bolt right below the middle of the seat, you can use a 6-pt set up to mount each of the ends on either side of midline, and still bring the tab that fastens into the harness latch through the hole. Formula cars routinely use 6-pt belts - I'm not sure if it has to do with the more reclined position of the driver compared to production cars, or (I think more likely) that formula cars have tube frames and better places to fasten the belts on either side rather than in the middle, since the floor pan is not structural.

If you're installing 5pt harnesses in a production car with street seats, there really is no good way to run the sub strap straight down - you have to run it forward over the edge of the seat, then down - but this negates the function of the strap, because you can now slide forward and down in an impact. You can cut a slit in the seat and run the belt down through that, but now you're not just putting a hole in your floor for the mounting bolt but cutting your seat up, too. The "alternative" to either an ineffective 5pt set up or cutting your seat is to use 6-pt harnesses as I mentioned. Because the ends can mount to the same points as the lap belts, you don't have to drill a hole in your floor. Because you sit on the two ends and bring the tab up between your legs (sort of like a parachute or climbing harness), you don't have to cut your seat.

artowar

iTrader: (1)

I'm familiar with what you've described. All I'm asking is where are the standard termination points for a 6-point sub belt?

macdaddy

Either bolts through the floor about 6" to either side of midline (of the seat) with the usual backing plates, or the cockpit floor tubes (for a tube chassis car).

the_glass_man

iTrader: (2)

Is this still the case? Cause he's the only game in town now that M2 is no longer.
*Edit*
NM, I just checked the site and it does seem that it still uses the stock mounts (wft?).
Wish I knew who made the M2 stuff, their bar and harness braces were top notch.

wickedrx7

iTrader: (14)

He use to not put on his website that it used the stock mount locations so I got a big surprise when I ordered the bar in '03. I was dissapointed with many things with the bar, but will only post his reasoning for the design:

From Chuck December 26th 2003:

"You probably don't know stock ends are stronger due to its construction. The dome style is a lot stronger than a flat piece of aluminum with two links welded on. That's why they are reused. The welding are 2 dimensional instead of just one, like the M2. M2 can't reuse the stock links because they center bar is just a piece of rectangular hollow steel metal rod. They can't make the ends of the center bar like mine. "

Needless to say, I have been using the bar but I am pretty sure I am going to get a roll bar which negates the use of this harness bar.

maxcooper

I've got a 6-point harness that I clip to the same eye bolts as the lap belt using the stock belt mounting holes. I put the sub straps through the space where the seat bottom and seat back meet and sit on them before they come up through my legs and attach to the bottom of the buckle/camlock. The sub straps are joined at the ends by a single plate that clips into the camlock.

The only thing I don't like about this setup is that it doesn't hold you as tightly in the vertical direction as a "straight down" sub strap setup would. Especially for short folks like me that have the seat more forward of the lap/sub belt anchors than a tall person would. But I believe the sub straps would serve their purpose in the event of an accident by preventing me from sliding out under the lap belt.

Note that the standard harness mounting eye bolts somewhat amazingly thread right into the stock holes -- I guess the seat belt bolt attachments are a federal regulation or something like that, hence the standard (non-Metric) threads.

-Max

zullo

Wow, that 6-point "wrap-around" setup sounds hard on the gonads in the event of a collision - or even when simply cinching them down tight.

It also seems the two straps would cut into / chafe the insides of your legs. Note that 3-inch 5-pts have a narrower sub strap, I assume to address this issue.

Either of these concerns caused you any problems?

Speedworks

about the mounting bar... What material, thickess,solid/hollow tube are we talking here?

I have those ring attachements as well so the betls can not be wrapped


If you have the "click-in attachements with ring bolts you could also run the straps going to the back directly to the bottom behind the seat and attach them to ring bolts attaching the seat rails? Or would that put tomuch stress on 1 spot?