Your opinion please.

[gsbaker]

If you could review crash test data for nine head and neck restraints, coming from 21 crash tests and generating over 200 load measures, which format would you prefer:

1. Individual charts for each load measure comparing side-by-side results for each product (we're talking ~15 charts),

2. A summary universal load analysis which distills all loads to a single value, but which is not intuitively obvious, i.e. second year engineering school, or

3. Both.

TIA

[JIgou]

As much as it might be a pain, I think you'd have to do both.

There are some folks who will just buy based on a recommendation from a trusted friend.
There are some folks who will want to read everything they can, but may not be able to interpret the second-year-engineering charts.
There are some folks who ARE engineers, and will want those charts.

It's only more work and money to produce both, right? :D

Personally, not seeing it I don't know if I could interpret option 2 properly or not.....so, I'd want the option of both just in case.

Jarrod

[gsbaker]

It's only more work and money to produce both, right? :D [/b]
In this case no. We are putting together all (option 3) of this stuff anyway for an SAE presentation next week, so there is no incremental effort.


Personally, not seeing it I don't know if I could interpret option 2 properly or not.....so, I'd want the option of both just in case.

Jarrod
[/b]
Makes sense Jarrod. Thanks.

To expand a bit, Option 1 presents such load measures as axial force, shear and bending about all three axes (X, Y & Z) for every product tested at both Wayne State and Delphi. That's the "choke a horse" part. This is very straight forward data but may leave drivers asking what it all means, only because there is so much of it.

Option 2 utilizes "principle stress analysis" which was discovered by a German structural engineer named Otto Mohr in 1882. It is a proven mechanism for taking all the load data and resolving it to a single number. This is exactly the type of thing people are looking for (a single measure), but unless you are familiar with the technique it will sound like mumbo jumbo. Worse, from a business standpoint, the uninitiated may think we are making this stuff up just to make our product look good--and we do look good--when in fact it is a classic analysis tool.

Another option is to express the summary loads as percentage head load reduction. That still has problems, but at least it is less intimidating.

We should probably throw it all out there and adjust as needed.

[tom91ita]

first of all, i appreciate you discussing this in public. that, imho, says a lot of you and your confidence.

i think it was discussed before, but i prefer that the powers that be at nasa or scca make the requirements for H & N restraints be something like x% reduction using sled test methods ABC and not make it to an SFI.

any company that can meet this should be approved. i can respect people's choices for the HANS, Isaac, R-3, etc.

i am one of the ones waiting on the side lines (i think we are relatively numerous since the last events i was at, the majority had horse collars or nothing) to buy something because i am not sure that my ~$1000 investment will be formally approved and the $#%@ rules always look like there will be something announced in the next couple of months.

i think i have been waiting a couple of months for a couple of years.

[Wreckerboy]

It depends upon your target audience. Remember, it's very easy to lose 'em up front with to much information, rather than piquing their interest with not enough.

I would suggest that a stepped approach is in order - start with a broad overview, and depending upon audience reaction and need, be prepared to delve into the minutia. Keep it simple, and avoid mind-numbing graphs with a zillion colours. It may look good to you, but to the guy sitting in the 23rd row it's a blur, and he or she will dose off.

[lateapex911]

Distilling the info into one number is tempting, but it's highly political and suspicious as well.

If YOU do it, the uninitiated will suspect you've chosen to give more value to your stong suits, and have "cooked the books", so to speak.

If an organization does it, there is still some suspicion that the organization did the same thing, but for other reasons.

I'd say that to the average person, if an organization did it it would bear more weight than if an individual company did it.

Then we have people who are critical thinkers.

They want numbers and math.

So, my answer is both, and show and explain the math for the idiots like me...LOL

[pballance]

To expand a bit, Option 1 presents such load measures as axial force, shear and bending about all three axes (X, Y & Z) for every product tested at both Wayne State and Delphi. That's the "choke a horse" part. This is very straight forward data but may leave drivers asking what it all means, only because there is so much of it.

Option 2 utilizes "principle stress analysis" which was discovered by a German structural engineer named Otto Mohr in 1882. It is a proven mechanism for taking all the load data and resolving it to a single number. This is exactly the type of thing people are looking for (a single measure), but unless you are familiar with the technique it will sound like mumbo jumbo. Worse, from a business standpoint, the uninitiated may think we are making this stuff up just to make our product look good--and we do look good--when in fact it is a classic analysis tool.

Another option is to express the summary loads as percentage head load reduction. That still has problems, but at least it is less intimidating.

[/b]

I am assuming, maybe wrongly, that you will include an unrestrained load measurement as well. It seems to me that if I know how much of a reduction is made by device "A" in axis X,Y, or Z and then compare that to the corresponding data of device "B" I could then start to evaluate the effectiveness of the particular device. In other words, device "A" might reduce 2 of the three loads substantially but the third could be off the charts.

Summary loads appeals to me for a quick look, but the real meat of the issue is in the data and the comparisons across the options. The hard part will be making the data representation simple enough for a casual user, not the SAE engineering types.

Just another $.02 worth form someone else who is waiting to make a purchase. I really do appreciate your being up front about the issue and opening yourself up to criticism. Thanks.

Paul

[x-ring]

Then we have people who are critical thinkers.

They want numbers and math.

So, my answer is both, and show and explain the math for the idiots like me...LOL
[/b]

Hey Jake -

Do you work in sales? :wacko:

I always have trouble explaining math using monosyllabic words. :P

[gsbaker]

I am assuming, maybe wrongly, that you will include an unrestrained load measurement as well.[/b]
Yes, there will be "baseline" data for all tests, i.e. a dummy with a helmet but no restraint, and is always listed as the first value on each chart.


It seems to me that if I know how much of a reduction is made by device "A" in axis X,Y, or Z and then compare that to the corresponding data of device "B" I could then start to evaluate the effectiveness of the particular device. In other words, device "A" might reduce 2 of the three loads substantially but the third could be off the charts.[/b]
Bingo. That's the entire purpose of the exercise. Here's an example of how different designs yield different strengths and weaknesses.

Good tension numbers for a certain group of designs:

http://www.isaacdirect.com/images/TestGraphs/Chart1.GIF

...and HANS rules the roost in frontal shear:

http://www.isaacdirect.com/images/TestGraphs/Chart3.GIF


The hard part will be making the data representation simple enough for a casual user, not the SAE engineering types.[/b]
Agreed, and with nearly 20 charts it becomes a challenge.


I really do appreciate your being up front about the issue and opening yourself up to criticism. Thanks.

Paul
[/b]
Anytime. The adults know that there is no such thing as a perfect product, and that all have strengths and weaknesses. We look pretty good when you add everything up, so we'll just leave it there.

[planet6racing]

Be sure to proof read (especially graph titles). Nothing casts doubt about data faster than careless mistakes (well, to me, anyway).

[gsbaker]

Thanks Bill.

[tom91ita]

i think i have a good idea that "z" is the vertical load or tension on the neck since "z" is elevation for other equations i use frequently (ChE). but just for the record, what is considered to be "x" and "y" in a car? is "x" forward motion and "y" lateral?

cause to the first users of grids in algebra, "x" is usually laid out on the paper for left to right, "y" is vertical and "z" goes into the paper and some have construed that to be forward or behind, etc.

also, the threshold of injury for a typical hard hit of 50 g's, etc. would be nice. i was quite impressed with the numbers on your website and i think a line for injury threshold would be a good way to illustrate what is above and below (essentially, inadequate and adequate), etc. would be nice and quick and most of all, intuitive.

and will there be any three dimensional graphs? cause in any crash video i have seen, the neck is going in all three directions at once and i am assuming that the resultant vector/force (i hope that makes sense cause it has been way too long since i had to use or listen to these kind of words!) is part of what has to be considered.

[gsbaker]

i think i have a good idea that "z" is the vertical load or tension on the neck since "z" is elevation for other equations i use frequently (ChE). but just for the record, what is considered to be "x" and "y" in a car? is "x" forward motion and "y" lateral?

cause to the first users of grids in algebra, "x" is usually laid out on the paper for left to right, "y" is vertical and "z" goes into the paper and some have construed that to be forward or behind, etc.[/b]
Yes, Z is vertical. The X axis is front-to-rear (from the dummy's perspective) and Y is left-to-right.


also, the threshold of injury for a typical hard hit of 50 g's, etc. would be nice. i was quite impressed with the numbers on your website and i think a line for injury threshold would be a good way to illustrate what is above and below (essentially, inadequate and adequate), etc. would be nice and quick and most of all, intuitive.[/b]
That's a good point. Unfortunately, threshold limits are not available for all measures, but we could include them where available.


and will there be any three dimensional graphs? cause in any crash video i have seen, the neck is going in all three directions at once and i am assuming that the resultant vector/force (i hope that makes sense cause it has been way too long since i had to use or listen to these kind of words!) is part of what has to be considered.
[/b]
This is the appeal of a summary measure. Given the bone geometry one can determine the unit stress and relate it directly to the bone strength. In other words, the net effect of all these loads acting simultaneously can be analyzed to be either above or below the fracture threshold. This would not require a 3D graph--although one could be used.

I think we will be keep it rather simple, with references to more detail as some sort of appendix.

Thanks all.

[John Herman]

For clarity, a simple diagram showing the x,y,z directions and also the the direction of the forces you are referencing. I invision a simple drawing of a head/neck/shoulders, a simple axis system imposed on it, and then the arrows showing the forces. For the engineering types, terms such as shear and axial make sense, but for the non-engineer, I imagine a picture with arrows (and maybe some very simple text) would be easier to visualize. For example, an axial force occurs when lifting someone by their head, a shear force occurs when the vertebrae of the neck want to slide across the top of each other. Then, given the mechanics of the basil (sp?) injuries, is there one or more of these forces which is considered more critical?

[gsbaker]

For clarity, a simple diagram showing the x,y,z directions and also the the direction of the forces you are referencing. I invision a simple drawing of a head/neck/shoulders, a simple axis system imposed on it, and then the arrows showing the forces. For the engineering types, terms such as shear and axial make sense, but for the non-engineer, I imagine a picture with arrows (and maybe some very simple text) would be easier to visualize. For example, an axial force occurs when lifting someone by their head, a shear force occurs when the vertebrae of the neck want to slide across the top of each other.[/b]
Something like this should work (at higher res, of course):
<div align="center">
http://www.isaacdirect.com/images/TestGraphs/SignConventionSmall.jpg</div>


Then, given the mechanics of the basil (sp?) injuries, is there one or more of these forces which is considered more critical?
[/b]
Yes, which complicates things further. We are not doing anyone any favors if they infer that all loads are equally dangerous.

Fz is the most important. It is the first value people want to see.

[planet6racing]

The above image is helpful, but would be more helpful if it listed Fz, Fx, etc.

How I wish I was travelling to the SAE show to see this presentation (and, more importantly, some of the crowd reactions!). :happy204:

[gsbaker]

The above image is helpful, but would be more helpful if it listed Fz, Fx, etc.[/b]
Done.

[planet6racing]

Thanks Gregg! I don&#39;t know why, but the whole "Yes" "No" thing didn&#39;t make sense to me until you put the My and Mz into there...

[RacerBill]

Others have already expressed my preference, but I will add my vote. Show us the numbers!!! Then tellus what they mean. My right brain is really fighting with my left brain. Pictures go a long way in describing the forces that are being measured, numbers allow me to evaluate options. Having a BS in Computer Technolgy (a form of engineering), I can appreciate the composite number you talk about and agree that it too would be useful as long as it is explained in terms that everone can understand and realize what it means.

Great work! Good luck with the presentation!

[gsbaker]

Show us the numbers!!![/b]
Not yet, Bill! We&#39;ve assigned the copyrights to the paper to SAE International. They cover their costs and provide peer-reviewed screening by selling copies, so we don&#39;t want to steal their thunder before it is published in the next few days. It is data we collected from various sources, however, so we have every right to present it in our own format eventually. We support SAE&#39;s work so we don&#39;t want to do anything that would hinder their efforts.

[John Herman]

Looks good to me. :023: :023:

[Z3_GoCar]

....
Option 2 utilizes "principle stress analysis" which was discovered by a German structural engineer named Otto Mohr in 1882. It is a proven mechanism for taking all the load data and resolving it to a single number. This is exactly the type of thing people are looking for (a single measure), but unless you are familiar with the technique it will sound like mumbo jumbo. Worse, from a business standpoint, the uninitiated may think we are making this stuff up just to make our product look good--and we do look good--when in fact it is a classic analysis tool.

Another option is to express the summary loads as percentage head load reduction. That still has problems, but at least it is less intimidating.

.....
[/b]

Mohr&#39;s theory states that the largest pricipal stress will be used to predict failure. I assume you&#39;re going to force normalize your graph to compress it down to one line. Also, for directional purposes I&#39;d suppose you&#39;d use the same directions used to define vehicle centered coordinates, i.e. x-left, y-fore, z-down and mx-pitch, my-roll, mz-yaw.

James

[gsbaker]

Mohr&#39;s theory states that the largest principal stress will be used to predict failure. I assume you&#39;re going to force normalize your graph to compress it down to one line. Also, for directional purposes I&#39;d suppose you&#39;d use the same directions used to define vehicle centered coordinates, i.e. x-left, y-fore, z-down and mx-pitch, my-roll, mz-yaw.

James
[/b]
X and Y axes are reversed in this convention. Like you, I initially assumed the opposite.

We will force normalize the graphs, yes. (I assume you are referring to resolving axial and shear loads to a value normal to the principle direction.) That&#39;s the question we are facing, i.e. different audiences may appreciate some but not all representations of performance, so we will probably layer the data somehow.

Personally, what I really want to get to is the point where we can compare the principal unit stress applied to the unit strength of bone, which is ~135MPa for a healthy 30-40 year old. This will tell us how close a particular design is to fracture for a given hit, and can be used as a basis for predicting the level of impact protection a design can offer--70Gs, 100Gs, 150Gs, etc. This is the kind of data people are looking for.

We probably won&#39;t publish this detailed level of data for some time. It relies on certain assumptions about the bone geometry and the mix between cortical and cancellous bone (different strengths) at the head-neck junction that needs to be confirmed. We&#39;ll take a SWAG at it in house (can&#39;t resist), but to publish it without verifying it helps no one.

At a minimum we will publish the raw load numbers.

[gsbaker]

Mohr&#39;s theory states that the largest principal stress will be used to predict failure.

...

James
[/b]Jim,

Is this what you had in mind:

http://www.isaacdirect.com/images/TestGraphs/Chart17.GIF
?

Titled for a bunch of biogeeks, these are the principal loads in the coronal plane. For normal people, that means the combined effect of neck tension, bending and shear in the up-down/left-right plane.

I know, I know, there should be no fixed plane associated with the true principal load, but we don&#39;t want to give away too much too soon.

Seriously, aside from titles, does anyone see any fundamental problem with this?

TIA

[leggwork]

Hi Gregg,
I&#39;d suggest embedding some explanatory text right with the chart graphic. Then, when the inevitable out-of-context spread around the internet happens, there will be some hope that the viewer gets a sense of what the graphic is trying the show, the significance, etc.
cheers,
bruce




Jim,

Is this what you had in mind:

http://www.isaacdirect.com/images/TestGraphs/Chart17.GIF
?

Titled for a bunch of biogeeks, these are the principal loads in the coronal plane. For normal people, that means the combined effect of neck tension, bending and shear in the up-down/left-right plane.

I know, I know, there should be no fixed plane associated with the true principal load, but we don&#39;t want to give away too much too soon.

Seriously, aside from titles, does anyone see any fundamental problem with this?

TIA
[/b]

[gsbaker]

Thanks Bruce. Good point.

There is much about this graph we don&#39;t like. It is fine for illustrating a point to a technical audience so there are no qualms about it&#39;s scientific merit. But we are very concerned that it may be misleading/misinterpreted. To do this properly one would calculate these loads for all planes and present the highest for each design. Unfortunately, we don&#39;t have that much data.

We will probably pull it from the Web but use it in the presentation

[gsbaker]

http://www.isaacdirect.com/html/OtherPages/TestGraphs.html

This is very rough, but we promised you guys on the A-Team first look. We&#39;ll flesh it out with explanations and such, but until we do we will not link to it on our site and ask that you not spread this around--no real damage if you do, but we&#39;d prefer not getting swamped with silly questions simply because someone doesn&#39;t get it.

Speaking of "getting it", we will probably trim this back significantly, or at least separate it into dummies, normal people and nerds categories. We&#39;d greatly appreciate your input in that regard.

Without a summary measure you have to be pretty up on this subject to put these loads in perspective. As it is, what is shown is a subset of what was presented at SAE. Do yourself and SAE a favor and get a copy of the paper for a more complete understanding of these test procedures.

TIA

[leggwork]

why is there a difference in the test results at WSU vs. Delphi - I thought these were standardized test procedures?
cheers,
bruce

[gsbaker]

why is there a difference in the test results at WSU vs. Delphi - I thought these were standardized test procedures?
cheers,
bruce
[/b]

Slightly different. Same dummy, but the seats are different and the crash "pulse" (G load) is different.

[HONDA69]

Greg:

This one&#39;s from a "Normal Racer" who knows he should be wearing some sort of Head and Neck Restraint Device!! On those graphs presented with a red Line in them is the red line the probable Fatality line?? Based on info presented Baseline vs. multiple H&N restraint devices, something is better than nothing, but for my use data provides me with info to make informed judgement.

[gsbaker]

On those graphs presented with a red Line in them is the red line the probable Fatality line??[/b]Close enough for decision purposes. The polite and official lingo is "IARV", which is an acronym for injury assessment XXX value (doing this from memory without references).

Both the ISAAC and HANS bump up against the IARV on some measures, which is why it is valuable to give consideration to a broad range of measures. Keep in mind that I&#39;ve spent the last couple days watching crash videos that are nothing less than rolling explosions, so the idea that you might be injured at 70Gs with modern safety gear, when you would be toast at 30Gs without it, is good to know but we need to keep things in perspective.

Yes, pay attention to the red line.

[tom91ita]

greg,

thanks for all of your open and sharing attitude. in today&#39;s environment, this is quite rare, especially in safety equipment. :023:

[gsbaker]

Thanks, Tom.

[gsbaker]

We did some slight editing of the presentation file and posted it here (http://www.isaacdirect.com/images/SAE3631Public.pps). Please right click and "Save as." ~6.5MB.

I think the videos are embedded in this file. Let me know if not and we will make other arrangements. You must see George White drive a Caddy into a wall at 60 mph. He broke his leg in two places.

Everyone have a safe weekend.

[greendot]

Hi Gary,
Let me also say thanks for being public with this and also for coming to the Waterford meeting with it Wed evening. I&#39;m the guy who asked the "political" question. :lol:
I am not gettting videos to play in the downloaded presentation.
Also, I should have asked Wed, but just what is the White device?

Bruce Wentzel

[gsbaker]

Let me also say thanks for being public with this and also for coming to the Waterford meeting with it Wed evening. I&#39;m the guy who asked the "political" question. :lol: [/b]
And with my answer went my credibility! ;) That was a great group; thanks for putting up with me.


I am not gettting videos to play in the downloaded presentation. [/b]
I was afraid of that. Apparently videos are linked to those files, not contained within. I&#39;ll get it fixed.


Also, I should have asked Wed, but just what is the White device?[/b]
Remember the video of the guy crashing the Caddy into the wall? That was George "It freakin&#39; works!" White, and you can buy an updated version in Kevlar from his operation for ~$400.

[itracer]

I think the videos are embedded in this file. Let me know if not and we will make other arrangements. [/b]

Try saving it as a Power Point show. (.pps) Then the movie should stay embedded.

~Jason

[greendot]

And with my answer went my credibility! ;) That was a great group; thanks for putting up with me.
I was afraid of that. Apparently videos are linked to those files, not contained within. I&#39;ll get it fixed.
Remember the video of the guy crashing the Caddy into the wall? That was George "It freakin&#39; works!" White, and you can buy an updated version in Kevlar from his operation for ~$400.
[/b]

You were paying attention. :D

I assumed the White was the same, but never saw the "nuts and bolts" of the system. Guess I&#39;ll do the research just to satisfy my curiosity.

BTW, here&#39;s a link that was posted to the Waterford site that bears on the topic:
http://news.bbc.co.uk/1/hi/england/hampshire/6217036.stm

[gsbaker]

Try the bottom of this (http://www.isaacdirect.com/html/OtherPages/CrashTesting.html) page.

I&#39;m nearly positive you have to link videos to PPT files, so those links will have to be reconstructed after everything is moved to your machine--or just watch them independently.


You were paying attention. :D [/b]
It&#39;s a rare moment. :)


I assumed the White was the same, but never saw the "nuts and bolts" of the system. Guess I&#39;ll do the research just to satisfy my curiosity.[/b]
George is here. (http://www.speedwaysafetyequipment.com/home.html)


BTW, here&#39;s a link that was posted to the Waterford site that bears on the topic:
http://news.bbc.co.uk/1/hi/england/hampshire/6217036.stm
[/b]
That&#39;s amazing. Just enough force to break the bone, but not enough for soft tissue damage. That&#39;s as close as you can cut it. Wow.

[gsbaker]

Try saving it as a Power Point show. (.pps) Then the movie should stay embedded.

~Jason
[/b]
Aha! That may be the answer. Thanks for the tip!

[gsbaker]

It&#39;s posted as a .pps file now. Let us know if there are problems.

Thanks all.

[greendot]

First, I used the link in message #34 and had to change it from .ppt to .pps to get it to open, but I couldn&#39;t get it to play a video. I&#39;m no PP expert so maybe it&#39;s just me.

[gsbaker]

Well, poop.

Try downloading the new file, which was saved as a .pps, as Jason recommended. If that doesn&#39;t work I&#39;ll turn the job over to someone who knows what they are doing. :)

I&#39;m having trouble testing this on my machine because it contains the videos, so the PP always finds them.

Sorry for the trouble.

[greendot]

Well, I don&#39;t know how to download that file. My best guess was to start at the message 34 link. Got a new link?

[gsbaker]

Right click and save this: http://www.isaacdirect.com/images/SAE3631Public.pps then run it in power point.

Jason says everything should load. If it doesn&#39;t it&#39;s his fault. ;)

[leggwork]

I still can&#39;t run the videos from within the pps, and the pps is the same size as the ppt was, so I suspect the videos are not embedded.
cheers,
bruce

[gsbaker]

Right Bruce. That doesn&#39;t work either, does it. It looks like the only option is to download the videos also and edit them into the presentation.

Sorry, but I don&#39;t see an alternative.

[leggwork]

fyi, just downloading the videos from here
http://www.isaacdirect.com/html/OtherPages/CrashTesting.html
and saving them in the same directory as the ppt file was enough to make them playable from within the ppt - I didn&#39;t have to relink or anything.
cheers,
bruce

[gsbaker]

Ah, that makes sense. Good work.

[leggwork]

Gregg,
could you elaborate on your comments in another thread on the results of the SFI meeting at the PRI show?
cheers,
bruce

[gsbaker]

We did not attend the meeting, so consider this rumor.

The rumor is that a proposal was made to reduce the allowable Fz load value (upper neck tension) from 3,000N to 2,500N. This would "decertify" the Leatt brace, which was "certified" in late October. Can&#39;t have any $395 H&N restraints out there, ya know.

So I wonder what 60 days of SFI "certification" cost those guys?

Also, the idea of a lower performance spec, 38.2, was dropped.

[gsbaker]

The above was confirmed this morning via e-mail with Leatt in South Africa.

[Xian]

The above was confirmed this morning via e-mail with Leatt in South Africa.
[/b]
That&#39;s pretty fuggin&#39; rediculous.

"Well, yeah, you met our "old" standard and if you manage to meet the new one we&#39;ll just lower it further." :(

[leggwork]

what I heard from Joe Marko is that the committee is now voting on the proposal to lower the Fz from 4000 to 2500N, so perhaps it isn&#39;t a done deal (??) I asked him what scientific evidence the reduction was based on, but haven&#39;t heard back from him yet ... (not holding my breath).

SFI Foundation -> SFI Trade Organization would be an appropriate name change right about now ...
cheers,
bruce




The above was confirmed this morning via e-mail with Leatt in South Africa.
[/b]

[JimLill]

what I heard from Joe Marko is that the committee is now voting on the proposal to lower the Fz from 4000 to 2500N, so perhaps it isn&#39;t a done deal (??) I asked him what scientific evidence the reduction was based on, but haven&#39;t heard back from him yet ... (not holding my breath).

SFI Foundation -> SFI Trade Organization would be an appropriate name change right about now ...
cheers,
bruce
[/b]

Yeah, they have ZERO credibility now in my book....... I bought a Leatt BTW so it smarts worse for me.

[gsbaker]

Ouch.

You guys should know that sanctioning bodies are NOT happy about this whole setup. Neither, for that matter, are high-end manufacturers of other safety gear who find their product reduced to a commodity by the standard.

During two weeks of everybody rubbing elbows at SAE and PRI, all we heard were complaints.

[leggwork]

presumably, Leatt have certification on their current device, and will have it until the recertification time comes around (two years, I believe). And, any devices that have the "SFI 38.1 certified" label on them should be acceptable to any sanctioning bodies forever since those don&#39;t expire.
bruce



Yeah, they have ZERO credibility now in my book....... I bought a Leatt BTW so it smarts worse for me.
[/b]

[gsbaker]

presumably, Leatt have certification on their current device, and will have it until the recertification time comes around (two years, I believe). And, any devices that have the "SFI 38.1 certified" label on them should be acceptable to any sanctioning bodies forever since those don&#39;t expire.
bruce
[/b]
But Leatt says the product is only good for three years.

[tom91ita]

Jim,

ouch. sorry to hear that. but this pretty much sums up why i don&#39;t have a h&n device. i don&#39;t trust the sanctioning bodies to keep the story straight long enough to get my investment from it.

i keep coming back to the HANS even though i think the Isaac is superior. where am i going to invest my $$ has a lot to do with if i can bank on using it. i would really like to get something in the off season since i use the downtime from racing to still use some $$ for buying next summer&#39;s brake pads/rotors, etc. so that it won&#39;t seem so expensive next summer. helps with the cash flow/budget process, etc.

i thought the leatt looked pretty good and thought i&#39;d wait til i saw one to decide.

tom

p.s., i&#39;d send a bill to sfi and ask for reimbursement. do it with a lawyer&#39;s letterhead just for grins and giggles!

[JimLill]

Tom, et al

I am early in Leatt&#39;s order queue and will give full report by end of January if they make their promosed delivery. Full report will consist of how it fits and feels in a seated in my race car environment, no on track until spring.