As the title suggests, I am looking 2 put harnesses into my Rx 7.
Where is the best mounting points for them....?????....
Thanks all
I\'ve seen a lot of people mounting them off their rear strut braces and am in two minds about how wise this is...
1) For stability mounting off the strut brace will be fine, the bar will be strong enough to cope with that.
2) in the event of a prang it may well collapse as it\'s not designed to cope with forces in that direction.
3) If you crash with enough force to deform the brace then the car\'s going to be badly broken so the brace will be the least of your worries.
I came to the conclusion that if I were to fit harnesses (it\'d be for track day stability) then I\'d also wear the inertia reel seat belt for protection in a crash.
Whatever you do - if you\'re only using hte harness make sure that you find a solid enough mounting point or it\'s your life you\'re risking...
I have got mine on my rear strut brace
For what it\'s worth I\'ve been considering this and was told in no uncertain terms that the rear brace is NOT strong enough and should not be used as a mounting point. There used to be a kit that bolted behind the seats but apparently the manufacturer no longer makes this (Chris at REWORX told me some time ago). If you do find out, let me know plaese.
Often the easiest place is to use the same moutning areas the inertia belts are attahced to - IE: remove the bolts holding in the inertia belts and repalce with the eye bolt of rthe harness. You must be careful not to have the rear should straps at too acute an angle though. When I was looking at the stripped shel of my car there appears to be threaded plates under the rear seats (presumably for rear seat belts?) - I would screw the eye bolts into these areas. You ideally want the eye bolts working in sheer, not traction - IE: an impact would try and snap the bolt in tow, rather than pull it out through the threads.
I wouldn\'t use a strut bar for the harness mounitng.
Good to hear that the rear strut brace isn\'t strong enough... Been thinking about this myself...
I was looking at:
http://www.mazdarotaryclub.com/forums/showthread.php?t=29241 but I\'m still undecided about the strength...
Now, what I am thinking, is mount eyes onto the rear seat belt mounts into the chassis, as this would definately be strong enough, then swing the harness\' over the brace to get them straight to the back of the seat... It would mean in a crash that the brace would still deform, but at least the harness\' would still be attached... Plus it may help absorb the impact a little as I know it hurts like fduk when nothing moves except your head ;)
I wouldn\'t swing them over the brace, let them have a straight run up to the seat and shoulders.
Quote from: TonyCI wouldn\'t swing them over the brace, let them have a straight run up to the seat and shoulders.
Angle would be wrong though. The shoulder part of the harness should be pulling you backwards not downwards.
Quote from: iaintAngle would be wrong though. The shoulder part of the harness should be pulling you backwards not downwards.
Thats exatly what its meant to do. Shoulder harness ideally wouldnt pull down at all (only backwards) and would run at a right angle out of the seat.
That\'s right, I\'ll dig out my blue book and check but really shoulder harness\' want to go straight back, which is often difficult but as straight as possible is best... I guess the boot floor would be OK, but again depends how thick it is... In a big accident you\'d want something else to peel away / buckle however as if you\'re 100% fixed without a HANS device you\'d be more likely to break your neck.
Bluebook will give you a degree of angle that is acceptable. It doesn\'t have to be 100% straight across your shoulders and down - using the far rear seat belt mounts should be ok.
I wouldn\'t swing it over the strut brace to get the straight angle becuase it:
a) puts unusual load on the belt (mid way down the webbing that is slung over the strut brace rather than in the full length of the webbing as it is taut)
b) should the strut brace deform or buckle (and it could easily do so in a big shunt) then the harness will suddenly find itself with an extra few inches to move before it holds you in the chair - IE: you will pull the harness tight on your shoulder with the tension over the strut brace - as soon as that tension is relieved due to the brace deforming or coming loose then the shoulder harness will be slack and you are going to start to flap around inside the seat. Not a good idea.
Mmm, good point there... Things are so much easier with a cage ;)
Aye, you should see the size of the one in the RX I\'ve just bought! And it still needs a couple of extra braces! A harness bar running across the rear cage uprights is a different kettle of fish to a strut brace.
Exactly! I was going to say earlier the harness bar\'s make life easier (as well as the cage stiffer!).
But as I\'d like to keep this as a road car (don\'t htink my gf will appreciate having 2 cars stripped out and caged! LOL!) it looks like the rear seat belt mounts would be the best bet?
My initial inspection of the car suggested they will be ok - I need to pick mine up and really start the prep yet though - I used similar mountings on my previous race car and they passed scrutineering, etc fine for 3 years with no remarks or worries.
I\'d hope so, given their supposed to be strong enough for seat belts!
In my MR2 it\'s pretty easy, just a couple of spreader plates behind the rear bulkhead and about 3 metres of spare harness length ;)
It\'s nice to hear people thinking of the rear purpose of harness\', as Iain said if it\'s mounted to the rear strut brace you\'d be wise to wear the inertia reel as well.
I hope this has helped n4bes as well ;)
Here are some pics of one of my cars with a proper set up!
As you will see it\'s quite simple really.
I still use my normal/standard seat belt for day to day use with the Harness in place as it is there with no bother.... best of both worlds.. :Thumbs-up
What about a rear strut brace that is designed for harnesses?
I know RE Amemiya used to do them with specific screw in mounting points on the bar itself.......are you saying its the bar that\'s the problem or the towers moving/deforming in a crash?
TRex, that looks ideal! Did you use the front seat belt mounts for the lapbelts or did you drill a couple of holes and use spreader plates seperately? And it looks like the rear seats are still useable in an emergency right?
Rob, I think it\'s the mounting of the rear strut brace that\'s the issue, it\'s 3 small bolts that are designed to be pushed together, not pulled forwards... Basically, the reason to use harness\' is that they\'re very safe in a big accident that *could* happen even on a trackday and it really is your life, so if you\'re using a bit of a dubious method, you\'d be better off with the Mazda designed interia reel seat belts ;)
You cant use a strut brace for support for a harness!!!! (x1000)
Look at a cage and the diagonals used within.
The strut brace is only designed to work in one direction and has no torsional strength in the front/back plane.
Harnesses aren\'t to be messed with, there was a guy at Thruxton killed because his wasn\'t tight. I spend ages rocking my shoulders back and forth on the grid trying to make sure there is no play in the belts.
They have a natural stretch and if not done up tight enough you will hit your head on the wheel.
If you want to use harnesses then why not take the rear bins out? You can then use the mounting points for the rear belts. Make sure the angle isn\'t too acute against the back of the seat, that can cause the belts to damage too.
The other option is, as already mentioned, use the normal belts. But get one of the clip ons that stop the belt from moving once its tight. They were selling them at the auto sport show last year for about £40 each.
Quote from: AtomicRexThe other option is, as already mentioned, use the normal belts. But get one of the clip ons that stop the belt from moving once its tight. They were selling them at the auto sport show last year for about £40 each.
These are the puppies:
http://www.cg-lock.co.uk/
I\'ve heard really good things about these, TBH I\'m getting tempted to try one out for the odd trackday rather than the whole harness thing... I like harness\' but I\'ve done tons of trackdays with just the 3 pointers fine, just end up with bruised knees!
Hi all,
Just thought I\'d follow up on this, I\'ve just got a couple of CG-locks, takes all of 5 minutes to install! Very easy!
So took it for a short test drive (any excuse!) and can say it really does make quite a difference, sure it\'s not full harness\' but it\'s pretty close, as you can pull the lap belt tight and hold your hips in place you hardly move in the seat! I\'m impressed! I\'d say try one of these especially if you\'re going to do a harf-ar$ed harness install ;) At least you know the Mazda seatbelts are attached very safely and have been tested to destruction!
Personally I think I\'ll be happy with one of these, but the true test will be on the track, so when I finally get the car trackworthy I\'ll let you all know.
i went for the nemesis half cage and used the rear horizontal bar for harnesses that loop over and around them. i couldn\'t use the rear seat belt mounts as i have no rear seats-just bins. there\'s no subsistute to being tightly strapped in with some good quality 4" belts!
i still have a cage for sale if anyone is interested.
4" belts....blimey....a tad overkill but you will be safe!!!
Just make sure they are tight....the number of times you see people with loose harnesses!! (just realised Ive repeated myself, but it is my biggest bug bear!)
As a quick tip, when you are fitting the belts, the ones that clip into the eyes, put either a split pin or a small cable tie through the hole to stop the clasp opening, it could wiggle itself to a point where it opens under load....I had to do all of mine at Pembrey when the scrutineer didn\'t like it, but to me it made good sense!
I\'m thinking of getting some harnesses and like TRex\'s set up. Daft question what type of harnesses would I need to fit where the standard seatbelts do?
e.g. would the clubman 4 point below be ok?
http://www.sabelt.co.uk/harness5.php
Also how easy to fit, looks reasonably straightforward but I am a bit useless :Hammer
Anyone know?