RF over the shell

Syllieann

New member
The new dorel quadruplets (guide 65, eb xrs65, etc) allow rf to the top of headrest or 40" even though the headrest is not reinforced and the vast majority of 40" kids will be above the shell. There is eps foam in the headrests. On the test bench, there's presumably no front seat or console to impact on rotation. I have some mild concerns about how this would play out in the real world. I understand that it's "safe" in the sense that it complies with the spec but I can't help but believe a taller shell would be safER. Please discuss and share your opinions. :D
 
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wendytthomas

Admin - CPST Instructor
Staff member
The Complete Air also allows to 40 inches or the top of the shell, and it's about as tall as you can get. Dorel still sticks to 40 inches (it's whichever comes first, not later, and not 40" if the head is above the shell). You only need support to the level of your eyes, so the one inch or equal to the top gives your head room to ramp up, and still support your head.

Wendy
 

Syllieann

New member
The avg kid will not be over the shell in the CA at 40" tall so it didn't give me the same sort of pause. That makes sense that it needs to be supported to eye level but I'm imagining a scenario where something contacts the back between the top of the shell and the top of the headrest during downward rotation. So, the head on the headrest would be stopped but the body in the shell would continue downward. Wouldn't that be like slamming the kid's head forward?
 

christineka

New member
Personally, unless I was an engineer and had actually run crash tests on these seats, I don't think I could accurately speculate whether dorel has made a mistake or not.
 

wendytthomas

Admin - CPST Instructor
Staff member
It'd be like slamming their head backward. Whiplash.

Likely they'd impact the headrest of the front seat, which is padded.

Wendy
 

jeminijad

New member
I've pondered this when people push the limits of their RF seats- technically, the child's head may be 1" from the top of the shell measuring "properly," but the crown of their head clearly extends over the shell.

Depending on the amount of space between the shell and the front seat headrest, is there foam cresting the top lip of the shell, how snug is the harness/heavy is the child etc I can envision the ramping up not being the problem, exactly- but striking the base of the skull hard on the lip of the seat when the child is descending back down, maybe.
 

Syllieann

New member
Personally, unless I was an engineer and had actually run crash tests on these seats, I don't think I could accurately speculate whether dorel has made a mistake or not.

I have no doubt it complies w/ the spec, I guess it's more about whether the spec is adequate in this regard. So, for a 40" tall kid, let's say your own kid, not someone you are advising in a professional capacity, would you have a preference for a seat w/ a taller shell or be perfectly fine w/ them being over it as long as the headrest is there?
 

jeminijad

New member
Personally, unless I was an engineer and had actually run crash tests on these seats, I don't think I could accurately speculate whether dorel has made a mistake or not.

And yet plenty of moms here make those kinds of calls to violate the professional advice of other highly trained individuals. Just not car seat engineers- there, we value decades of training and experience.

That snark isn't directed towards you, Christineka, just what I've been reading.
 

Brianna

New member
I've pondered this when people push the limits of their RF seats- technically, the child's head may be 1" from the top of the shell measuring "properly," but the crown of their head clearly extends over the shell.

Depending on the amount of space between the shell and the front seat headrest, is there foam cresting the top lip of the shell, how snug is the harness/heavy is the child etc I can envision the ramping up not being the problem, exactly- but striking the base of the skull hard on the lip of the seat when the child is descending back down, maybe.

Doesn't this picture illustrate measuring "properly"? http://www.car-seat.org/showthread.php?t=30201 I don't see how you could measure properly and have the crown extending over the shell?
 

jeminijad

New member
Doesn't this picture illustrate measuring "properly"? http://www.car-seat.org/showthread.php?t=30201 I don't see how you could measure properly and have the crown extending over the shell?

I'll try to find a pic that illustrates what I'm thinking about.

Kind of if you are crouching so that your eyes are level with the childs's head, I've seen some that the crown would peek over the shell on the sides. Probably this is more likely when the sides of the seat turn downward more sharply. But my wording didn't specify.
 

christineka

New member
I have no doubt it complies w/ the spec, I guess it's more about whether the spec is adequate in this regard. So, for a 40" tall kid, let's say your own kid, not someone you are advising in a professional capacity, would you have a preference for a seat w/ a taller shell or be perfectly fine w/ them being over it as long as the headrest is there?

There are a whole lot of ifs, when discussing my kids. I really don't have to think about it because no 40" tall kid of mine will have their head even with the top of the guide, etc headrest in the top position. My kids have small heads and short torsos. I also have no desire and no plans to buy a dorel seat. It's not that I don't trust dorel seats. I simply don't like them and already own seats I do that will last my youngest to booster age.

It's all hypothetical, but seeing as I believe sk/diono and have used the radian with shoulders above the top slots and have no qualms about using a classic marathon forward facing, I also would use a dorel seat to the stated limits.
 

Syllieann

New member
Another thought, I don't see how it's any different than using ma70 or bv70 over shell, which is a no-no. I can personally attest to the fact that there are plenty of gov't issued specs that leave gaping holes in regard to real world performance. In my previous life designing products to these specs, upper mgmt made the choice that for us we would guarantee real world performance even if it priced us out of the market on some things. There are other companies that made different choices even though they met the spec. I think my personal experience in this regard is making me paranoid about this shell vs. headrest issue.
 

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