I need to install the 5th belt of my harnesses in my NB Miata. On the driver side, I have a Sparco Junior seat mounted to a Sparco slider, mounted to a Planted bracket. On the passenger side, I have the same seat, mounted directly to the Planted bracket.
In the current Exocet thread, Keith, you wrote "Use a 5 point harness instead of 6. Some seat bases (like the ones from Planted) have sub mounting points built into them, so the sub belt moves with the seat."
The Planted brackets I received don't have a mounting point there, but, I would assume I could drill through the bracket and create a mounting hole. Having never installed harnesses, what is the preferred method for mounting the sub belt?
These are the brackets I have:
And these are the seats in the car:
I wouldn't want to drill through anything for fear of weakening the seat mount. If it were me, I would wrap the sub belt around the rear cross like you do on a harness bar and call it done. The bracket is the strongest mounting point (save drilling the floor pan and adding a backing plate).
Thought - the purpose of the sub strap is to keep the buckle stabilized so the shoulder belts don't pull the lap belts off of your pelvis "so you get a SIMPSON tattoo on your liver". With that in mind, anything that keeps the sub strap mounted as straight down as possible should be best.
Do you really ever need to move your seat? Why should any part of the belt be attached to the seat?
imgon
Reader
3/4/17 1:38 p.m.
Are you running with a particular group, SCCA, NASA, local club....? If so maybe ask on their forums. I drilled a hole in the rear cross bracket on my slider for the sub belt mounting point. I feel like it is safe but I don't play an engineer on TV or in real life so not sure if it is an unsafe idea. To me it will take a lot of force to shear the bolt or tear the hole out of the bracket. Use good hardware, grade 8 or better and I think you will be OK.
NordicSaab wrote:
I wouldn't want to drill through anything for fear of weakening the seat mount. If it were me, I would wrap the sub belt around the rear cross like you do on a harness bar and call it done. The bracket is the strongest mounting point (save drilling the floor pan and adding a backing plate).
That seems like a brilliant solution. I'll investigate further.
Knurled wrote:
Do you really ever need to move your seat? Why should any part of the belt be attached to the seat?
I need the ability to move the driver seat because I'm going to share the car with my daughter, who is only 5'1". She needs the seat much closer to the pedals than I do. I have one side of the lap belt attached to the frame of the car (the outboard factory lower seatbelt anchor point) and the other side of the lap belt is attached to the ear of the seat bracket (you can see it in the photo pasted in my first post). The shoulder belts are wrapped around the harness bar of the roll bar.
Mine are wrapped around the seat mount so they move with the slider. Make sure you keep the belt as short as you can do you can shove it under the seat when you use the standard belts.
Do not drill into the mount it is too narrow to be strong enough.
