Harnesses vs Inertia belts

[Neal H]

My main problem on the road with harnesses was the inability to easily lean foward to get a decent view at junctions. This is a problem in an Elise/Exige which has a number of blind spots! Aren't harnesses illegal on the road in some countries - Japan for example? I seem to recall Japanese spec 2-eleven's being fitted with inertia reel belts.

 

Ideal world is to have both fitted - three point belt on the road but harnesses on track. Safety issues aside, I love the way harnesses lock you in place which gives you a better feel for what the car is doing.

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I'll take my chances with a 4 point harness any day thanks.

 

I used to run 4 point harnesses but never again. There's a reason they are being progressively  outlawed in motorsport.

 

I don't have issues with people using harnesses - just the blanket "they are safer". Yes they have advantages in a very select number of scenarios but come with their own baggage. 

Edited August 13, 2015 by ads_green

[C8RKH]

I used to run 4 point harnesses but never again. There's a reason they are being progressively  outlawed in motorsport.

I'm no expert but this is news to me. Can you confirm which forms of motorsport have progressively outlawed them as every form of 4 wheel motorsport I spectate seem to use 4 point harnesses.

 

They are also used in planes extensively (not commercial passenger flights) for the reasons outlined earlier, that they hold you in place, stop you moving around, dissipate the crash forces more evenly across the body etc. 

 

I can see pro's and con's for both, but hurtling at 60 mph towards a tree I think I would prefer to be fully strapped in, preferably with a reinforced safety seat around me, than having my upper half of body, neck and head rolling and sloshing around all over the place over the top of a diagonal chest belt that was crushing my pelvis and putting all the restrain force through my sternum and right or left shoulder!

 

I don;t have a choice in my Evora, just have the inertia reel, but can see benefits to both but I am truly intrigued with regards to the progressive outlawing of 4 point harnesses in msport.

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Following on from the Exige V6 thread I inadvertently high jacked:

 

I find driving with harnesses great and generally would spec cars with them.

However in my opinion I'm not doing it for safety reasons as a I believe harnesses have some serious gotchas:

 

Racing harnesses are designed for high speed impacts usually encountered on track. The principle is simple - the car's occupants are safer if they stay in the main passenger cell of the car. Being ejected during a crash is usually "a bad thing". As such the harnesses are made from different material, much wider and importantly feature a very different thread construction. 

 

All these things together result in a belt that is strong and doesn't stretch anywhere near as much in an impact. Good things when you want to keep the people in the car.

The extra width of the material and the extra shoulder contact point do allow the energy to be spread over a larger area.

 

Bad Points about a harness on the road though:

- visibility.

you simply can't move about to view the road especially at junctions. You can adapt but you always have to be aware of the limitations.

 

- impact reduction

Conventional belts stretch a huge amount during an impact (I've seen a few) where the idea is to increase the time the impact force is applied to the body. So the same change in velocity over a longer time will be felt as a softer impact. A good example is hitting a hammer on a desk then repeating with some test with thick piece of rubber between them. The total energy of the impact is the same but the rubber slows down the application making it much harder to do any damage to the table.

This is important as a big and common complication of a vehicle crash is internal deceleration injuries (not from me - my wife is a trauma neurosurgeon so will take her word on it). As harnesses don't stretch as much the occupant will experience a faster deceleration than an inertia belt wearer. 

 

There is a flip side to this though... Inertia belts (even with multi stage pre tensioners) are similar to airbags in that they are most effective on the first impact. If you are unfortunate enough to be involved with a multiple impact scenario then harnesses will hold together better.

 

- head restraint

Holding the torso in place is great however on the road very few wear HANS devices. Even without a crash helmet this can cause some neck injury in a front impact.

 

- roll over

If the car hasn't got a full cage then being held bolt upright with no opportunity to change position can be devastating in a roll over scenario. At least with modern Lotus based cars they have the rear roll bar but this isn't a full strength bar and will deform on impact.

 

- side impact

Whilst you are less likely to "fall sideways" out of a inertia belt similar things apply as with the roll over. if you side impact into say a tree then the tree will always win. Plenty of cases where the tree simply pushes its way through the passenger cell. One of my (very lucky) friends found this out when he crashed into a tree and was still in his seat but over on the passenger side. Being bolted to the chassis would prevent this movement but do nothing to stop the tree.

 

- submarining.

with 4 point belts (even the ASM variety) you can shoot under the lap belts and out of the harness. Inertia belts don't do this as the pre tensioner will pull the belt tight enough. 5/6 point belts obviously prevent this but are pain on the road. 4 point belts are being phased out of motorsport so they might as well be for the road too.

 

- stupid owners

Inertia belts are hard (still possible) to get wrong.I can't count the number of people I've seen put on harnesses in a way that makes me wince... The common ones being too loose or the buckle up near their belly button. It takes time to fit a harness properly and that breeds contempt.

 

 

I guess there are plenty of accidents where people walk away from wearing no belts (just google "russian dashcams"!) and similarly for all manner of belts. I use harnesses and probably always will... But I do so knowing quite clearly the pro's and con's of each and accept the implications. 

 

 

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I'm no expert but this is news to me. Can you confirm which forms of motorsport have progressively outlawed them as every form of 4 wheel motorsport I spectate seem to use 4 point harnesses.

 

 

From the lotus cup rules for example:

1.3.2 All participants are required to have a minimum of four-point safety harnesses. A minimum of five point harnesses is required for all race group participants with non-expired FIA or SFI 16.5 certification.

 

So 4 points with a current FIA certification will be valid however there is a definite move to phase them out.

[qwerty123]

Ads is right.

With a harness and no airbag to arrest your head in a full stop scenario (with no HANS device) you are going to get whiplash at least or Basal skull fracture at worst.

The airbag, designed in conjunction with a conventional seatbelt with pre-tensioners will protect your head much better. The harness will keep you routed to the spot but won't help your noggin! (Unless you wear a helmet and HANS routinely, you strange person...)