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      10-11-2011, 12:47 PM   #23
Richbot
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ISAAC is what I'm using right now, since 2005. It's popular amongst the dirt track crowd (I've heard they do lots of flips). I've had several hard hits, all of them offset to some degree from 30 to 90 degrees (because in the real world you're not on a crash sled) with no halo seat, and it's worked as advertised. I bought a halo seat for the car in my sig after my previous car was crashed too hard to rebuild economically and promptly stopped crashing, so maybe everybody should just buy a halo seat for that reason.

The ISAAC "shock absorbers" are there partially for decel but mostly to provide head mobility, and once they're extended they act just like tethers but without the give in the webbing, relying on the give in the harness webbing to slow the decel. The full containment seats work great in a front or front-offset impact but as soon as the acceleration vector is pointed away from the backrest they start to lose effectiveness. That's where the HNR is supposed to take up the slack in the modern safety system scheme, and where IMO the HANS is pretty well useless compared to better designs that weren't written into the SFI 38.1 spec. Not a big deal and I'll probably buy a HANS anyway since my SRF only allows my head to move sideways about 3" on either side, but it's something to think about.
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      10-13-2011, 07:16 AM   #24
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Thanks for the info. I've heard about ISAAC, but never seen one person. Are the connecting pieces solid links with ball joints at the ends that are connected by the damper in the middle? If so, then I can see how the damper provides mobility when expansion/compression speeds are low.

They reference a SAE paper on their website, and there is footage from 30 degree crash tests (as compared to HANS). HANS comes loose as criticized. I slowed it down and watch it, and it is indeed clear that a Halo extension would not change the outcome in that scenario since it comes out of the harness when the neck would just about clear the extension as the body moves forward. Although they don't reference the peak deceleration rate for that test (maybe the SAE paper does), they say it is meant to mimic a stock car crashing into the wall. One can argue the forces in crashes involving lower power/grip cars might be lower in general, but one can always find a way to put anything into a barrier/wall/tree that would yield high/comparable gs. The lateral sheer data are also interesting. I'll get a hold of the paper.

http://www.isaacdirect.com/
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      03-31-2013, 12:50 PM   #25
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As I would like to get one of these and have some questions, I need to revive this thread.

Can anybody tell me what the "sliding tethers" and "contoured vs. straight" options are when placing an order?

Thanks.
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      03-31-2013, 06:46 PM   #26
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Quote:
Originally Posted by MTROIS View Post
As I would like to get one of these and have some questions, I need to revive this thread.

Can anybody tell me what the "sliding tethers" and "contoured vs. straight" options are when placing an order?

Thanks.
You definitely want the sliding tethers so you can turn your head side 2 side, albeit for a few degrees only. Contoured vs straight, sorry it's been a while but I remember I opted for contoured.

Don't forget to order the correct nutwashers for your helmet. Using the HANS tethers is also an option but you can plan for that later on.
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      04-01-2013, 10:01 AM   #27
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Quote:
Originally Posted by mid-corner fun View Post
You definitely want the sliding tethers so you can turn your head side 2 side, albeit for a few degrees only. Contoured vs straight, sorry it's been a while but I remember I opted for contoured.

Don't forget to order the correct nutwashers for your helmet. Using the HANS tethers is also an option but you can plan for that later on.
Thanks a lot for your comments and advice!

After further discussion with the Simpson rep., I opted for the straight version which will be a better fit for my regular seat. Contoured seems to be designed for seats which are really tilted backwards, such as in Drag Racing.
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      04-01-2013, 11:52 AM   #28
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Quote:
Originally Posted by MTROIS View Post
Thanks a lot for your comments and advice!

After further discussion with the Simpson rep., I opted for the straight version which will be a better fit for my regular seat. Contoured seems to be designed for seats which are really tilted backwards, such as in Drag Racing.
I could have sworn that they recommend the contoured version for street seats and the straight one for race seats, oh well.

Also..just fyi, a lot of people don't use the foam insert but if you don't you'll ruin your regular seats. I've added a thin layer behind their foam insert and that solves the problem, you'll see what I'm talking about when you get the R3.

GL!
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      04-04-2013, 10:51 AM   #29
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The link is broken...are we talking about the hybrid pro? Kind of like the necksgen?
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      04-04-2013, 11:07 AM   #30
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The link is broken...are we talking about the hybrid pro? Kind of like the necksgen?
R3

as the title says
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      04-04-2013, 01:04 PM   #31
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Yup, the R3 from Simpson (which is now distributing the Safety Solution products): http://simpsonraceproducts.com/head-neck/r3.html
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      04-04-2013, 02:38 PM   #32
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Hmm...never seen that one. I might have to see where I can try one. I wear a HANS but now that I'm instructing I want something that I can wear in a student's car.
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