Seat belt mount heght

[RAYLEE29]

Hi, section 31 page 2 no. 17
"A Lap/diagonal belt "effective upper anchorage" location must be at least 140mm from the longitudinal centre line of the seat (see note 14)."
knew id seen something somewhere.
I read it as only applying to normal seat belts and not harnesses but ive spaced mine accordingly as i may use some ordinary belts or harnesses.
so ive put in two top mounts per side and may put an extra one near the floor below the top mount so i can use an inertia real belt as i find harnesses a pain to use
anyway there it is
hope it helps
Ray

[Enoch]

Hi Ray, that is for a "normal" seat belt with a diagonal strap that goes from (on driver's side) right shoulder to left hip, harnesses are not diagonal belts. I was quite surprised that there was not a requirement for spacing of upper mounts when there is one for lower mounts. I guess I will just do mine so they are comfortable. Thanks for your responses and for taking the time to look it up.

[spud69]

Originally Posted by Enoch

Hi Ray, that is for a "normal" seat belt with a diagonal strap that goes from (on driver's side) right shoulder to left hip, harnesses are not diagonal belts. I was quite surprised that there was not a requirement for spacing of upper mounts when there is one for lower mounts. I guess I will just do mine so they are comfortable. Thanks for your responses and for taking the time to look it up.

The main thing he will check Dave is the the upper mounts are not lower than your shoulders so that they do not go up from the mounts to pass over your shoulders. They need to be level or above your shoulders. The strength of the brackets and bolts, plus that when your belts are tight you can release the catch and comfortably remove your arms / shoulders from the belt without slackening them off, he will try this himself a few times. Stick with the industry standard 7/16 unf 8.8 grade bolts and nuts (should be marked on the bolt) just to be sure.

Maybe we'll get another first time pass.......

Regards...AndyH

[carlknight1982]

so you cant take the strap over the roll bar and secure it to a point lower down the chassis, it has to be on the rolll bar?

[Enoch]

Thanks Spud. I have made mine so that they are higher than my shoulders, I guess I have to hope that the tester isn't 6ft7 tall

[snapper]

.so you cant take the strap over the roll bar and secure it to a point lower down the chassis, it has to be on the rolll bar?

I think you'll find you can, the roll bar becomes the "effective seat belt mount" for the mounting point height measurement.
The real mounting points should of course be upto standard and the bar the belts loop over will be assesed for strength "as if they were mounted there" as in the event off a crash all the load would be consentrated on the mounting and the bar.
I did this at SVA, any retractable belt system uses this method as the mechanism is usually lower than the place the belt retracts into.
IVA has not changed the requirements from the SVA from what I have read.

[james3004]

so if you put them where the book specifies they would be wrong?
The reason I ask is because i haven't decided what seats to get yet but want to start making the roll bar soon.
I was going to make it like ash has done, but i'm unsure of the height of the cross brace and the hole spacings for the bosses to be welded in

[HandyAndy]

Originally Posted by james3004

I was going to make it like ash has done, but i'm unsure of the height of the cross brace and the hole spacings for the bosses to be welded in

Hi James,

I have just finished my roll bar / harness mounting & have also done similar to Ash,s build, have a look at the thread titled "Hi All" in the "off subject" section, there is a photo showing my roll bar/harness mounting position...........if this is similar to how you intend doing yours then I can give you the measurements I used .

cheers
andy

[james3004]

Yes andy that's how i was gonna do it but maybe with a smaller diameter cross bar, yours looks really fat?

[HandyAndy]

Originally Posted by james3004

Yes andy that's how i was gonna do it but maybe with a smaller diameter cross bar, yours looks really fat?

makes up for me being a skinny wotsit lol.

it certainly is very thick walled I must admit

let me know if you would like the dimensions etc.

cheers
andy