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Yes. You will mount the lap belts to one of the unused holes in the rails.
Here is my current setup.
I'm not exactly a safety-****, but I like the idea of the lap belts being mounted to the steel seat studs going thru the bottom of the car rather than the aluminum mount. That said pretty sure if you were in a frontal impact so hard to rip your lap belts out of 1/2'' thick aluminum you'd probably be cut in half, but I still like the idea of mounting to steel.
So, I do have a concept to make some sexy, super strong, low profile eye bolts that will mount right to the studs in the back of seat. These eyebolts would be custom machined pieces and offered as an add on, but there are many ways to mount lap belts so not everyone might want to use these, so I wouldn't include them with every mount.
I'm not exactly a safety-****, but I like the idea of the lap belts being mounted to the steel seat studs going thru the bottom of the car rather than the aluminum mount. That said pretty sure if you were in a frontal impact so hard to rip your lap belts out of 1/2'' thick aluminum you'd probably be cut in half, but I still like the idea of mounting to steel.
So, I do have a concept to make some sexy, super strong, low profile eye bolts that will mount right to the studs in the back of seat. These eyebolts would be custom machined pieces and offered as an add on, but there are many ways to mount lap belts so not everyone might want to use these, so I wouldn't include them with every mount.
Mark can you show picture of how to mount the lapbelts with your new seat mount to the studs as you mention above?
With my previous setup there was a crossbar in back of the seat that had eyelets that the lapbelts and sub belts would clip on to.
Here's our CAD mock-up of the rear hook to mount your lap belts. We'll make them out of hardened 17-4PH which has a yield strength of 190,000psi. Figure something like $50 for the pair. I'll get material ordered for these today and try and get some ready to ship this week.
Very nice work Mark. I'm thinking I am going to need one of these. I'm getting tired of breaking off the air inlet on the top of my helmet as I try to squeeze into my car!
Alright folks this is the last weekend to get in on the giveaway, and the pre-sale price goes away August 9th.
We're shipping a mount today to a giant - 6'7" in a C7Z. Knowing he's gonna need the seat all the way to the back, we came up with a different stud for the rear. Otherwise the stud would impinge on the seat, or you'd have to raise the seat an inch to clear the stud. That might not be a problem for some guys, but when you're 6'7" headroom is at a premium. Unfortunately the larger seat studs are a fact of life, so we chopped them down, and used a nordlok washer and thin hex nut. This way your seat clears the stud and only sits a half inch above the mount. We will most likely just use this setup on all mounts going forward.
2020 Corvette of the Year Finalist (track prepared)
C3 of Year Winner (track prepared) 2019
That rear inner bolt/nut looks like a M'fer to tighten. Mine are not that low and it was a hand-cramping nightmare to reach. Not a critique, just an observational based on experience.
That rear inner bolt/nut looks like a M'fer to tighten. Mine are not that low and it was a hand-cramping nightmare to reach. Not a critique, just an observational based on experience.
Yup, it's gonna suck. That's why we got rid of the nylon lock nuts. At least with this setup you'll finger tighten and then get a couple cranks on it with an open ended wench. Won't be fun, but will be possible.
Lap belts should be mounted so they are at the proper angle to go through the seat pass through and they shouldn't go around the back of the seat to get to the pass through. They need a straight shot from the mount to the pelvis. Anything that deflects them from that straight path becomes part of the restraint and can be subject to up to 3000 lbs of shock load in an incident. Seats will deform under that kind of a load and when that happens you get slack in the belt.
Here are the SFI Guidelines:
LAP BELTS
Lap Belt Angle: -45° to -80° from the horizontal
• Belt should ride within the curvature of the pelvic bone preferably just below the iliac crest
• There should be clear passage through the seat opening without webbing being corded or binding on edges of seat openings with a direct path to the mounting point
• The webbing should not ride against any hardware such as seat mounting brackets, bolts, or tabs
• Lap belt adjusters should be clear of the seat openings. Pull-up adjusters if outside the seat opening should be a minimum of 2” below the opening when the lap belt is tightened
• Belts to the mounting point should be as short as possible mounted beside the seat and never behind the seat
• Lap belt should be allowed to pivot freely at the mounting point
• Webbing should be allowed to pull on hardware in plane (straight)
By the time we're done I feel we'll meet most of the important parts of those SFI guidelines. You can see the quick version we did below for a concept eye bolt. Kinda missed the fact that the eyebolt needs to turn 90 degrees. Also going to move it a little further back and out to the side, so the lap belt angle is the closest it can be to the correct angle. I would rather have the lap belts running to a solid steel bolt attached to the frame rather than some guy drilling a hole in our aluminum mount and threading in some eyebolt of unknown quality. Every integrated lap belt solution I've seen seems to be a compromise in some fashion, and I believe this will have less compromise than most of them.
Last edited by Mark@AMT Motorsport; 08-04-2017 at 07:13 PM.
Put me down for 2 on the pre-sale Mark. I don't need them immediately. New seats go in next month. I'll communicate with the options. Waiting to see how the lap belt hook comes out.
07-26-2017, 09:27 PM
