4 point Harness in BBW
Discussion
Hi,
I am considering fitting a four point harness in the 450SE. I have heard of different mounting options and a bloke I know has done this...
www.pixeltechnology.co.uk/wedge/harness.html
Comments??
Is this safe? is this legal? would it pass an MOT?
MikeB
I am considering fitting a four point harness in the 450SE. I have heard of different mounting options and a bloke I know has done this...
www.pixeltechnology.co.uk/wedge/harness.html
Comments??
Is this safe? is this legal? would it pass an MOT?
MikeB
I would be a bit worried about fixing to the GRP even with large plates. If the car was involved in an accident, there is potential to pull the steel plates straight through.
There is some mention in the "bible" that even if you fix harneses, you still require conventional seat belts. (something to do with the MOT)
If I was to fix a harness I would look for a fixing on the chassie. If you have a copy of the bible there is a mention of something similar in fitting a role bar.
There is some mention in the "bible" that even if you fix harneses, you still require conventional seat belts. (something to do with the MOT)
If I was to fix a harness I would look for a fixing on the chassie. If you have a copy of the bible there is a mention of something similar in fitting a role bar.
I've considered mounting a harness in this way and if you do the sums a plate of area 0.4m square is sufficent to withstand a 500Kg load ( big bloke with a 5G stop) with a fair bit of safety factor. so it should be fine, however as Pete says a roll-over bar should be considered before the harness.
Matt
Matt
GreenV8S said:
If you have a rollover bar, attach the harness to the rear stays. If you don't have a rollover bar, don't fit a harness. The harness will keep you upright in the seat, which will be briefly rather painfull if you roll the car since it will basically land on your head.
Totally agree, having taken the hoop apart to recover it and finding that it is only fiberglass with a plate either side I realised it wasn't going to offer much protection if I rolled the car. As I wanted to fit harness's this was the primary reason for fitting the roll bar.
Hi
There is a way of making a frame for bolt onto the chassis which will allow you to atach the harnesses onto the back shelf, I cant remember the link to this site, ill have a look, its a good alternative to the roll over barr
Putting steel plates behide the back fiber glass wall will spreed the pressure about but could make the fiber glass crack and fail- not the best idea.
By lay you must retain the rachet seat belts to pass an MOT, the lay says 4 point harnesses arent safe enought
, may be this is why F1 cars arnt road legal 
You should use a steel plate under the floor to mount the seats on, this gives it added strenght and support, specialy if you put bucket seats in and think about the roll over barr to stop this happening to you [url]www.t-v-r-services.co.uk/towerviewraceser.html[/url]
Cheers
Campbell
There is a way of making a frame for bolt onto the chassis which will allow you to atach the harnesses onto the back shelf, I cant remember the link to this site, ill have a look, its a good alternative to the roll over barr
Putting steel plates behide the back fiber glass wall will spreed the pressure about but could make the fiber glass crack and fail- not the best idea.
By lay you must retain the rachet seat belts to pass an MOT, the lay says 4 point harnesses arent safe enought
, may be this is why F1 cars arnt road legal You should use a steel plate under the floor to mount the seats on, this gives it added strenght and support, specialy if you put bucket seats in and think about the roll over barr to stop this happening to you [url]www.t-v-r-services.co.uk/towerviewraceser.html[/url]
Cheers
Campbell
19560 said:
There is a way of making a frame for bolt onto the chassis which will allow you to atach the harnesses onto the back shelf, I cant remember the link to this site, ill have a look, its a good alternative to the roll over bar.
Yep, I've seen it done this way too. Quite neat and the harness holds you steady on track days.campbell said:
By law you must retain the rachet seat belts to pass an MOT.
Which law is that? My local MoT guy says the opposite?
sevans said:
Having taken the hoop apart to recover it and finding that it is only fiberglass with a plate either side I realised it wasn't going to offer much protection if I rolled the car. As I wanted to fit harnesses this was the primary reason for fitting the roll bar.
Hmmm. Structurally that hoop construction is strong and weight efficient on the same theory as honeycomb F1 construction.
The problem for most people with roll over bars is that because they need to be at least 150mm above the top of your head/helmet to be of any use you cannot then fit the roof on. Speaking to Richard at Moore racing he told me that he overcomes this problem by having approx the top third of the RO Bar detachable so that you can store it in the boot when the top is up - only bad news is if you want to do a track day with your roof up. lol Of course for shorter wedge drivers this isn't a problem at all.
Yes it's strong and weight efficient and might even support the weight of the car if very carefully placed on it, but it's still nowhere near strong enough to count as roll-over protection. The only thing I would count on from the hoop/roof/windscreen is that they act as a skid plate. You might get squashed but hopefully not get bits of flesh ripped off by the road surface.
Ideally the rollover protection would be far enough above your head to stop you coming anywhere near the road, and the MSA specifies 150mm clearance. But this simply isn't practical for an everyday car.
My theory is that in the heat of the moment you can bend quite a long way and if it means you end up with your chin on your chest you will probably still be alive. Yes more protection would be better, but it just isn't practical for an everyday car.
I used to think the deal with the MOT was that the seat belt had to be kite marked (which most harnesses aren't), but I think these days it is enough to be E marked. In any case I think at most MOT places it would probably come down to the tester's attitude most of the time. If he reckons it's OK because it looks safe and is in good conditon, you OK. If he reckons it's non-standard and he isn't having any of it, he probably isn't going to pass it no matter how right you are.
Ideally the rollover protection would be far enough above your head to stop you coming anywhere near the road, and the MSA specifies 150mm clearance. But this simply isn't practical for an everyday car.
My theory is that in the heat of the moment you can bend quite a long way and if it means you end up with your chin on your chest you will probably still be alive. Yes more protection would be better, but it just isn't practical for an everyday car.
I used to think the deal with the MOT was that the seat belt had to be kite marked (which most harnesses aren't), but I think these days it is enough to be E marked. In any case I think at most MOT places it would probably come down to the tester's attitude most of the time. If he reckons it's OK because it looks safe and is in good conditon, you OK. If he reckons it's non-standard and he isn't having any of it, he probably isn't going to pass it no matter how right you are.
Tower View fitted a harness mount in my 400 a few years back, as described in the Bible I think. An eye bolt screws through the rear shelf into a mount connected to the chassis. The other two points use the existing left and right seat belt mounts, although I have retained the standard belt as well for those who dont wish to use the harness (the missus). Haven't got a roll bar, will take my chances in the event of a flip, especially as they don't exactly enhance the appearance of the Wedge.
GreenV8S said:
Yes it's strong and weight efficient and might even support the weight of the car if very carefully placed on it, but it's still nowhere near strong enough to count as roll-over protection. The only thing I would count on from the hoop/roof/windscreen is that they act as a skid plate. You might get squashed but hopefully not get bits of flesh ripped off by the road surface.
I think that that's pessimistic. I have seen Wedges that have rolled and the occupants have walked away. I do however agree with your basic point that the standard roof cannot be considered to be a roll over bar.
GreenV8S said:
Ideally the rollover protection would be far enough above your head to stop you coming anywhere near the road, and the MSA specifies 150mm clearance. But this simply isn't practical for an everyday car.
IMHO by using the solution offered by Moore racing it is practical. Whatever.
GreenV8S said:
My theory is that in the heat of the moment you can bend quite a long way and if it means you end up with your chin on your chest you will probably still be alive.
I think that that's very optimistic.
The rear boot panel will pull away in the event of an accident and are simply just not up to the job. They need to be fixed to the chassis or roll bar or roll cage. Period. No exceptions.
The height measurement is 5 cm not 150 mm. Just chceked it in my 2005 Blue Book.
None of the Tassie coupe racers have a problem nor the convertibles with a hard top. The problem comes with complying with drawing Q60 for open top cars where an extension is needed to create a clear safety zone. Most of this add a bit on so the bar is still there.
The 520 has a similar roll cage and the roll bar is underneath the roof. I have only been queried once about this and that was with the roof off . Put the roof back on to show why it didn't protrude and the Scrutineer was happy. The cage has been also been checked and approved for the car's competition car log book that it needs as it competes on slicks. The other trick is that the bar is actually behind me so that I can't hit it.
As for the window strength. It flexes quite nicely and has let the roof panel fly off at speed (140 mph). I now have internal latchs to retain it. Yes I have seen cars roll and get away with it but I wouldn't trust it at all.
>> Edited by shpub on Thursday 27th January 07:50
The height measurement is 5 cm not 150 mm. Just chceked it in my 2005 Blue Book.
None of the Tassie coupe racers have a problem nor the convertibles with a hard top. The problem comes with complying with drawing Q60 for open top cars where an extension is needed to create a clear safety zone. Most of this add a bit on so the bar is still there.
The 520 has a similar roll cage and the roll bar is underneath the roof. I have only been queried once about this and that was with the roof off . Put the roof back on to show why it didn't protrude and the Scrutineer was happy. The cage has been also been checked and approved for the car's competition car log book that it needs as it competes on slicks. The other trick is that the bar is actually behind me so that I can't hit it.
As for the window strength. It flexes quite nicely and has let the roof panel fly off at speed (140 mph). I now have internal latchs to retain it. Yes I have seen cars roll and get away with it but I wouldn't trust it at all.
>> Edited by shpub on Thursday 27th January 07:50
I believe the MOT problem with 4 pint belts is that if they have the aircraft style release buckle, joe public will be confused and not be able to release you in an accident and your out for the count. The baynet style is universal and all idiots and undo it, answer would be find a 4 point which uses a baynet/push button release system or retain the old belts as well just for the MOT
I've had Willans 4-point harnesses fitted in my SEAC since it's rebuild. The original seat belts were removed. I've never had MoT problems, but I've always been to 'TVR friendly' MoT testers (handbrake - what handbrake 
).
The harness is attached to the rollbar and the rollbar is really stongly mounted. I wouldn't feel happy with mountings just in fibreglass.
As for the roll bar being unattractive....
When my car was being displayed in the 'Ultimate Muscle Car' display at Goodwood FoS two years ago I was told that Lord March was discussing the 'originality' of my car and was heard to comment that the roll-bar couldn't be original...
it looked far to good to be factory fitted
). The harness is attached to the rollbar and the rollbar is really stongly mounted. I wouldn't feel happy with mountings just in fibreglass.
As for the roll bar being unattractive....
When my car was being displayed in the 'Ultimate Muscle Car' display at Goodwood FoS two years ago I was told that Lord March was discussing the 'originality' of my car and was heard to comment that the roll-bar couldn't be original...
it looked far to good to be factory fitted
paul gotts said:
Tower View fitted a harness mount in my 400 a few years back, as described in the Bible I think. An eye bolt screws through the rear shelf into a mount connected to the chassis. The other two points use the existing left and right seat belt mounts, although I have retained the standard belt as well for those who dont wish to use the harness (the missus). Haven't got a roll bar, will take my chances in the event of a flip, especially as they don't exactly enhance the appearance of the Wedge.
Reading all these posts - this one sounds the best for the road .. but roll bars sound good but have their down sides ..
i.e If you don't have a helmet on and hit the bar with your head in an accident - you will probably do more damage to yourself than the accident will cause
They are noisy (fuel pump noise !
rev-erend said:
roll bars sound good but have their down sides ..
i.e If you don't have a helmet on and hit the bar with your head in an accident - you will probably do more damage to yourself than the accident will cause
They are noisy (fuel pump noise !
Very true, although a properly positioned bar will be out of reach of your head. They certainly do transmit more noise into the cabin though.
All seat belts must carry the BS "kite-Mark" to be road leagl.
Most 4 point ones have not been BS tested and are not so marked, however I beleive there are a few that have and as such are legal.
Ready to be shot down on this, if I have read the law wrong..
>> Edited by pebbledash on Thursday 27th January 14:23
Most 4 point ones have not been BS tested and are not so marked, however I beleive there are a few that have and as such are legal.
Ready to be shot down on this, if I have read the law wrong..
>> Edited by pebbledash on Thursday 27th January 14:23
Speed Matters | Wedges | Top of Page | What's New | My Stuff