Modifying Black Vinyl Seats for Submarine Belt

[BrewCityCobra]

I was wondering if anybody has modified their Black Vinyl seats for the submarine belt (so it is properly positioned)? Is it worth trying or are there better options out there if you want to low-back look?

[mburger]

I want to do the same. I was going to bring them to an upholsterer but haven’t yet.

[i.e.427]

The main purpose of the sub belt is to keep the lap and shoulder belts in place. You can effectively bolt the sub belt to the floor directly in front of the standard seat and it will do it's job. If you're going to be racing, get a racing seat.

[Jeff Kleiner]

The main purpose of the sub belt is to keep the lap and shoulder belts in place. You can effectively bolt the sub belt to the floor directly in front of the standard seat and it will do it's job. If you're going to be racing, get a racing seat.

Precisely. Don't run without it; your belts will never fit right or work as intended.

Jeff

[AdamIsAdam]

Good info. How important is wearing the shoulder belts for casual rides? I typically just wear lap and sub.

[JohnK]

The main purpose of the sub belt is to keep the lap and shoulder belts in place. You can effectively bolt the sub belt to the floor directly in front of the standard seat and it will do it's job. If you're going to be racing, get a racing seat.

The Simpson instructions are pretty clear that they do not recommend this. I know that lots of folks have done it, and it's definitely better than nothing and is probably fine for street driving, but it's not what Simpson recommends. I have the leather seats, and I've had the same thought about taking them to an upholstery shop to have them add a slot for the crotch strap. I also want to add an inflatable lumbar bladder, as well as seat heaters. Not sure if a slot can be cut in the seat heaters for the crotch strap.

[Jim1855]

The goal is to keep the lap belt across your hips not through your gut. At the hips the belt will work. At the gut you'll get cut through to your backbone and it won't be pretty.

If the anti-sub belt is attached under the seat but around the front it may not be absolutely proper but it will be way better at controlling the lap belt position than nothing. A race seat is a great idea and will help in many more ways than just facilitating the belts.

Always wear the shoulder harnesses. If you don't want to please do a pivot check to see where you'll faceplant.

There's a lot of discussion about oil pans being below the frame rails, too much horsepower, proper tires, driveshaft loops and more. All of this you can control, the moron pulling out in front of you not so much.

Jim

[egchewy79]

I just installed my harness today. Anchored submarine belt about 3-4" in front of my seat mount through the floor. 129314

[i.e.427]

The Simpson instructions are pretty clear that they do not recommend this. I know that lots of folks have done it, and it's definitely better than nothing and is probably fine for street driving, but it's not what Simpson recommends.

I made no mention of the Simpson instructions. I did make it clear however, that if you're going to track the car, (race) get a racing seat.

https://www.kirkeyracing.com/category/Series55V/55v-series---vintage-class-bucket

[JohnK]

I made no mention of the Simpson instructions. I did make it clear however, that if you're going to track the car, (race) get a racing seat.

https://www.kirkeyracing.com/category/Series55V/55v-series---vintage-class-bucket

Sorry, I assumed you were referring to the Simpson harness as that's what comes with the kit. However, the guidance against routing the crotch strap over the front of the seat vs. through a pass-through isn't unique to Simpson. In fact, below is SFI's guidance. I'm not trying lecture here. I just think that if someone prefers not to put a pass-through in their leather or vinyl seats, or go to race seats, they are better off going with a harness system that doesn't rely on a crotch strap for the anti-submarine function. The Schroth Profi II ASM FE, for example, is a 4 point harness that has anti-submarine technology in the shoulder harness and doesn't need a crotch strap. IMO, that's a better option for the street than routing a crotch strap around the front of the seat.

https://www.schrothracing.com/item/profi-ii-asm-fe/competition-harnesses

https://www.sfifoundation.com/wp-content/pdfs/guidelines-bulletins/Seatbelt%20Installation%20Guide%2006-05-12.pdf

https://thefactoryfiveforum.com/attachment.php?attachmentid=129318&d=1590987113

[mburger]

I’m not sure that the belt bolted to the floor will do it’s job properly as it was designed if routed over the front of the seat. My sub belt is bolted to the floor and wraps over the front of the seat, but I’m taking mine to an upholsterer to have it routed properly, through the seat at the angle recommended by the belt manufacturer. If I’m going to have a sub belt, it will be eventually through the seat. I’ll wear it like that and any passengers will as well. I haven’t installed my heaters yet so that’s a bridge I’ll need to cross when I get there.

AdamIsAdam, I never wore the shoulder harness after first buying my car and my Mk1 didn’t have a sub belt at the time. I was doing 30 minding my own, when a pickup pulling a boat blew a red light. I almost T boned him. From that night on, I wear the shoulder harness and have added the sub belt. If I was going racing, I’d change the harness (expired), seat, tires, suspension, etc., etc...

[AdamIsAdam]

I'll start wearing shoulder. Very good points made here. Thanks.

[walt mckenna]

I'll start wearing shoulder. Very good points made here. Thanks.

There's one other wrinkle I'll add to the 5 point harness/standard seat discussion. At my first on-track tech inspection, the inspector denied my entry because of two things, both related to the seat. First, was the submarine belt draped across the front which was already mentioned here. The second, was the condition where the shoulder belts, when pulled tight, will preload your spine setting you up for serious injury should you have an accident (a high back seat with opening for shoulder belts are above your shoulders and so hold you tight to the seat without preload).

[AdamIsAdam]

There's one other wrinkle I'll add to the 5 point harness/standard seat discussion. At my first on-track tech inspection, the inspector denied my entry because of two things, both related to the seat. First, was the submarine belt draped across the front which was already mentioned here. The second, was the condition where the shoulder belts, when pulled tight, will preload your spine setting you up for serious injury should you have an accident (a high back seat with opening for shoulder belts are above your shoulders and so hold you tight to the seat without preload).

ok, so let me restate so I'm sure I understand what you're saying: If the mounting point of the shoulder belts is lower that my shoulder height, then it's compressing my spine when pulled tight and therefore very bad?

would it help to wear the should belts close but not so tight as to pre-load the spine? Or is the only answer to either mount above shoulders or at least install high back seats where the belts feed through them above the shoulder?

I was considering high back seats for safety's sake anyway, but of course the look is not as good unless I find a vintage looking high back that works.

[walt mckenna]

ok, so let me restate so I'm sure I understand what you're saying: If the mounting point of the shoulder belts is lower that my shoulder height, then it's compressing my spine when pulled tight and therefore very bad?

would it help to wear the should belts close but not so tight as to pre-load the spine? Or is the only answer to either mount above shoulders or at least install high back seats where the belts feed through them above the shoulder?

I was considering high back seats for safety's sake anyway, but of course the look is not as good unless I find a vintage looking high back that works.

I answer to your first question is yes. When I sat in the standard seat, the pivot point for the shoulder belt was the stop of my shoulder, not the seat or the pivot point in the trunk.

To the second question on how tight to run the shoulder belts is a personal one and so I will not comment.

As far as the third question on harness mounting, there is a little room to raise the belt where is comes through from the trunk, but you would have to add some additional structural square tubing to that already existing to maintain the pivot point strength needed.

[BrewCityCobra]

I was hoping to modify the vinyl seats to both maintain the classic look but still have proper belt location (E.g., the submarine belt). Sounds like if worse comes to worse I can always modify the bottom of the seat to try to at least get that location right.

Hoping to do track days and autocross with the kit once its done - are the low backs that much of an issue (or a rule breaking issue)?

[Ian G]

I have had a lot of compliments about my high back Kirkey seats.

[rsw81]

Hey guys, given one of the tangents on this thread relates to NOT wearing the shoulder straps. I have to advise against this, even in street driving. In background, I'm a spinal cord injury doctor. Shoulder belts were invented due to incidence of "Chance" fractures (look them up, it isn't pretty) that is caused by sudden, excessive and focused forward flexion of the spine. This can result in paralysis. Hardly worth the minor effort of wearing the shoulder straps in my opinion.

Regarding the location of the shoulder straps. Yes, ideally the straps would be anchored above your shoulder line, unless seated backwards like a babyseat in which they need to anchor below the shoulder line. Yes, this has to do with how the seat belts load the spine during an accident. However, a low shoulder anchor is still better than no shoulder anchor as noted above.

[AdamIsAdam]

I have had a lot of compliments about my high back Kirkey seats.

PICS please! And details.




Hey guys, given one of the tangents on this thread relates to NOT wearing the shoulder straps. I have to advise against this, even in street driving. In background, I'm a spinal cord injury doctor. Shoulder belts were invented due to incidence of "Chance" fractures (look them up, it isn't pretty) that is caused by sudden, excessive and focused forward flexion of the spine. This can result in paralysis. Hardly worth the minor effort of wearing the shoulder straps in my opinion.

Regarding the location of the shoulder straps. Yes, ideally the straps would be anchored above your shoulder line, unless seated backwards like a babyseat in which they need to anchor below the shoulder line. Yes, this has to do with how the seat belts load the spine during an accident. However, a low shoulder anchor is still better than no shoulder anchor as noted above.

THANKS! message received.

[mburger]

Good information Rob. My spine is fused C1 to T2 and spinal injury never seems far from my mind. Also makes for quite a show watching me get in and out especially with the top on! :-)

[AdamIsAdam]

This thread has me re-thinking installing high back seats. I just want something that looks as 1960's as possible.

Also, I'm sure this has been discussed elsewhere, but for street use, does anyone know for sure how often simpson harnesses should be replaced? Seems odd that OEM belts can last for decades but these have a 2 year shelf life. I'm wondering if that's just for extreme duty (ie, racing) in which case I can understand. But these garage queen's harnesses are probably safe long after the 2 year date comes and goes.

[edwardb]

Also, I'm sure this has been discussed elsewhere, but for street use, does anyone know for sure how often simpson harnesses should be replaced? Seems odd that OEM belts can last for decades but these have a 2 year shelf life. I'm wondering if that's just for extreme duty (ie, racing) in which case I can understand. But these garage queen's harnesses are probably safe long after the 2 year date comes and goes.

The date coding is required for race sanctioning bodies. IMO they're plenty safe for street use after the date if they're in good condition. From their website:

How often should I inspect and/or replace my harnesses?

We recommend replacing your harnesses every 2 years. This is a requirement for most sanctioned racing.

You should inspect your belts before every use. Replace belts that have nicks, cuts, excessive wear, fraying and/or have been exposed to harmful chemicals or the environment.

Proper harnesses are a very important factor in safety. Replace any belts that experience a crash or anything other than normal use. Do not use the harness system ever again, even if it appears OK.

Again, most sanctioning bodies require racing harnesses be replaced 2 years after the date stamped on the SFI tag. Consult your sanctioning body for more information.

Do you re-certify harnesses?

No. Our first priority is your safety and we do not believe this is a safe practice.

[AdamIsAdam]

Thanks, i did read through their site. I guess for me, I'll continue to investigate new high back seats. If/when I find one I like, I'll install them along with a fresh set of harnesses. They're not that expensive anyway.

[JohnK]

Hey guys, given one of the tangents on this thread relates to NOT wearing the shoulder straps. I have to advise against this, even in street driving. In background, I'm a spinal cord injury doctor. Shoulder belts were invented due to incidence of "Chance" fractures (look them up, it isn't pretty) that is caused by sudden, excessive and focused forward flexion of the spine. This can result in paralysis. Hardly worth the minor effort of wearing the shoulder straps in my opinion.

Regarding the location of the shoulder straps. Yes, ideally the straps would be anchored above your shoulder line, unless seated backwards like a babyseat in which they need to anchor below the shoulder line. Yes, this has to do with how the seat belts load the spine during an accident. However, a low shoulder anchor is still better than no shoulder anchor as noted above.

Rob, thanks for sharing your thoughts in this thread. I'm curious what you think of using a HANS device with low-back seats for track days? Is this of value, or is a high-back seat required for the HANS device to be effective?

[GTBradley]

I'd like to know where the information is coming from regarding the anchor point of the shoulder belts. I checked mine and they are definitely below the top of my shoulder and that made me think, if this is wrong why is FFR doing it this way? So I got my Simpson manual out for belt installation and Simpson advises to: " (https://bucketeer-6a1c3869-11ee-400c-8e6c-029add2ed33c.s3.us-east-1.amazonaws.com//app/public/spree/theme_assets/23580/original/Simpson-Performance-Seating-Positions-Seatbelt-Installation-Manual.pdf?1575913197)Anchor shoulder straps at point zero to 10 degrees below the top of the shoulder. Note: Preferred mount is as close to shoulder as possible." (https://bucketeer-6a1c3869-11ee-400c-8e6c-029add2ed33c.s3.us-east-1.amazonaws.com//app/public/spree/theme_assets/23580/original/Simpson-Performance-Seating-Positions-Seatbelt-Installation-Manual.pdf?1575913197)

This would indicate to me that the high back seats, or attaching the belts, as some do, to the roll bar causes the shoulder belts to be too high.

[JohnK]

The SFI guidance (See the link I posted above) is very similar, i.e, 0 deg. to 20 deg. from horizontal, with -10 deg. being optimal. The thing to keep in mind is that this is in the context of an upright seat with a recline of up to 25 deg. If you look at the diagrams you'll see that what they are effectively saying is that the top of the shoulder harness should be roughly perpendicular to the plane of the back of the seat, in other words pulling straight back and not down so it's not pre-loading the shoulders. Their diagrams always conveniently show a driver whose shoulders are exactly even with the top of the seat or the harness slot. If you're tall enough that the top of your shoulders is above the seat belt slot, this is what creates the steeper harness angle and pre-loading.

As far as why FFR does it this way, I just have to assume because it's "authentic (ish)" looking. To make the shoulder harness attachment points SFI compliant would pretty significantly change the look of the seats and/or rear cockpit wall of the car. They also don't mention anything about installation of the crotch strap in the instructions, and just leave it up to folks to figure out for themselves if/how to install them.

[GTBradley]

Not to start a debate, I'm just trying to reassure myself that my shoulder harnesses aren't going to injure me or my passenger because they are mounted incorrectly. The Simpson diagram does not show a seat at all and the SFI doesn't say that the seat back has any influence on the belt. It would concern me if I thought these belts installed with up to a -20 (-10 for Simpson) degree down angle was dangerous, but I have to take Simpson's installation instruction as the proper way to install and use these and they do state clearly that a flat to down angle from the shoulder is proper: "Anchor shoulder straps at point zero to 10 degrees below the top of the shoulder." Beyond -10 degrees I understand would not be appropriate. Anybody else seeing it differently than me?

[1932]

Puting kirkey road race seats in 33 and having hard time getting seat back support bracket made, and working with waterfall.
Please every one use the harness with 5 point. We love the power and speed, so be safe and drive more days!!

[David Hodgkins]

re: shoulder harness height. There is also an option to anchor the shoulder belts on the rollbar: This is before I trimmed-to-length and heat-sealed the ends of the straps:

https://thefactoryfiveforum.com/attachment.php?attachmentid=48566&d=1450040878

:)

PS No, the car is not that yellow. Getting accurate pics with my old cell phone was impossible.

[RoadRacer]

A related thread with a great answer to how to put a hole through a seat. I'll be trying this: https://thefactoryfiveforum.com/showthread.php?36245-Ebrake-reach&p=414139&viewfull=1#post414139

[JohnK]

That's cool. Thanks for sharing.

This thread prompted me to search again for seat options that have a bit more bolstering than the stock leather seats and also have a pass through for an anti-sub strap. I like the functionality of the Kirkey seats, but I'm not a huge fan of the look (sorry, I hope I don't offend anyone). I've seen examples where folks have had their Kirkeys re-upholstered with added foam and whatnot, and those look better to me. I came across a thread from a couple years ago where someone mentioned this seat:

https://www.ultrashieldrace.com/catalog/product/seats-hot-rod-classic-bucket/cobra-bucket-seat/

This looks very promising to me, as structurally it looks very similar to the Kirkey and aesthetically it looks a lot more like a nicely re-upholstered Kirkey. It also has an anti-sub strap slot already built in. I can't really seem to find any feedback on this particular seat anywhere, but Ultrashield seems to be a respectable seat company in general.

[davekp]

The problem with anchoring to the roll bar is the seats are not aligned with the roll bar- they are offset.

[JohnK]

That's true, but the seats aren't really aligned with the slots in the rear cockpit wall either ;)

[Badfish]

Good thread. When I had my Corbeau high back seats, they had those plastic inserts in the seat pan for the sub belt. Very non-intrusive in those seats, but the roadster seats are a bit softer, so may (or may not) bother your legs. I want to figure something out, don’t like using the 5 point as a 4 point.

For shoulder harness, I had a bar welded into the roll bars. Significantly more comfortable.

[BrewCityCobra]

re: shoulder harness height. There is also an option to anchor the shoulder belts on the rollbar: This is before I trimmed-to-length and heat-sealed the ends of the straps:

https://thefactoryfiveforum.com/attachment.php?attachmentid=48566&d=1450040878

:)

PS No, the car is not that yellow. Getting accurate pics with my old cell phone was impossible.

Are those the "vintage aluminum race seats?" If so did those holes come stock? Perhaps that is the perfect balance between low-back seats and proper support/protection.

[AdamIsAdam]

so who's running a great looking seat that looks period correct in a Cobra yet provides head support (and then also higher shoulder harness support)? I found these:

129418

129419

129421

Miata modified seat:

129420

[rsw81]

Rob, thanks for sharing your thoughts in this thread. I'm curious what you think of using a HANS device with low-back seats for track days? Is this of value, or is a high-back seat required for the HANS device to be effective?

A HANS device would be fantastic, I just can't imagine how it could get secured in a low back seat. If someone has a solution to this, I'd love to see it.

[walt mckenna]

A HANS device would be fantastic, I just can't imagine how it could get secured in a low back seat. If someone has a solution to this, I'd love to see it.

A HANS device is simply sandwiched between your body and the shoulder harness, so should work with any seat. If you decide to go with the HANS device, swap out the 3" shoulder belts for 2" (Simpson #30010BK) because the 3" belts are too wide for the HANS belt slot. If you decide to try to track a car with low backs, check with your local club to be sure they would pass tech inspection.

[SSNK4US]

Dave where did you get those rollbar mounts?
And as always tell your brother FIGHT ON! ;)

[tonywy]

This is a great discussion, can anybody show how/where they mounted the sub belt.

[rsw81]

A HANS device is simply sandwiched between your body and the shoulder harness, so should work with any seat. If you decide to go with the HANS device, swap out the 3" shoulder belts for 2" (Simpson #30010BK) because the 3" belts are too wide for the HANS belt slot. If you decide to try to track a car with low backs, check with your local club to be sure they would pass tech inspection.

My mistake, thanks for the education. I was under the impression that the HANS device also anchored behind the seat to a solid/frame member. The more you know!

[fostia]

Roadracer had earlier posted what I had planned to do. https://thefactoryfiveforum.com/show...l=1#post414139

I just finished doing my passenger seat and I think it came out alright. Right now the submarine belt is just bolted to the seat frame. I think this is okay because that frame is directly bolted to the real frame.

I removed the faux leather pull over part from the little rod underneath, cut out the foam, inserted the plastic through thingy, bolted the submarine belt to the frame and then put the pull over back on the little rod.

130188130189130190

[Badfish]

That looks really good, nice job.

[RoadRacer]

Roadracer had earlier posted what I had planned to do. https://thefactoryfiveforum.com/show...l=1#post414139

I just finished doing my passenger seat and I think it came out alright. Right now the submarine belt is just bolted to the seat frame. I think this is okay because that frame is directly bolted to the real frame.

I removed the faux leather pull over part from the little rod underneath, cut out the foam, inserted the plastic through thingy, bolted the submarine belt to the frame and then put the pull over back on the little rod.

130188130189130190

Turned out great!! I plan on doing this with my seats when they show up.

[Mark K]

Roadracer had earlier posted what I had planned to do. https://thefactoryfiveforum.com/show...l=1#post414139

I just finished doing my passenger seat and I think it came out alright. Right now the submarine belt is just bolted to the seat frame. I think this is okay because that frame is directly bolted to the real frame.

I removed the faux leather pull over part from the little rod underneath, cut out the foam, inserted the plastic through thingy, bolted the submarine belt to the frame and then put the pull over back on the little rod.

130188130189130190

Are those suicide doors?

Edit: Nevermind - I just realized it's a hot rod.

[Railroad]

Roadracer had earlier posted what I had planned to do. https://thefactoryfiveforum.com/show...l=1#post414139

I just finished doing my passenger seat and I think it came out alright. Right now the submarine belt is just bolted to the seat frame. I think this is okay because that frame is directly bolted to the real frame.

I removed the faux leather pull over part from the little rod underneath, cut out the foam, inserted the plastic through thingy, bolted the submarine belt to the frame and then put the pull over back on the little rod.

130188130189130190

Very nice work. I was throwing this around mentally, and just realized I put seat heaters in.
I could have probably worked around the heat pads, during installation, but guess I will have to pass for now.
I like the mod.