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Why rfing height matters so much?
- Thread starter Baylor
- Start date
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Phineasmama
New member
Because the shell needs to be there to protect the child's head from hitting anything, especially the seat in front of them. The kid and the seat will move quite a bit during a crash.
Baylor
New member
YES! exactly this.. If jumbled up legs is not a safety concern rearfacing, then why does it matter?
Phineasmama
New member
Oh yeah I see what you mean. I honestly think the manufacturers who put a 40" height limit on their seats are on crack or something and just don't realize that kids don't have proportional torsos and legs, and some may fit at 40" and some wont' 
carseatcoach
Carseat Crankypants
The manufacturer states that it matters.
We don't know why it matters.
We can choose to disregard a clear and repeated statement because we don't understand why it was made, or we can use "parental choice" to assume the statement doesn't actually apply to us.
We don't know why it matters.
We can choose to disregard a clear and repeated statement because we don't understand why it was made, or we can use "parental choice" to assume the statement doesn't actually apply to us.
Well I could see the force loads being different from longer legs, perhaps putting more of a stress on the restraint. Some people here don't follow height restrictions but I wouldn't because it isn't a chance I'd be willing to take with my kid...just like using a seat a couple months off expiration, headrest support on the Monterey or random finicky rules of seats.
thekatie
New member
carseatcoach said:
As a manual reader and step-by-step "I can't deviate from a recipe to improvise if my life depended on it" kind of person, that's what I believe. The manufacturer says so, so we do it.... My own personal "but whyyyy?!" comes from how not every manufacturer says that, so why is it life or death with seat A but totally acceptable with seat B. Or the ambiguous "40 inches or head one inch from top of shell", where the manufacturer *probably* means 40 inches even if there are 5 inches above the head, and only throw the other part in for the kids who are all torso and have only 1 inch of shell at a mere 37" height.
And honestly, I doubt it will ever be an issue with my kids. They're tiny. I think my 20 month old just finally hit 30". But it's still something I wonder about all the time.
LISmama810
Admin - CPS Technician
I believe it's largely due to dummy size and growth chart averages. Manufacturers often dumb stuff down so everyone can understand it, and saying "40 inches" is easier than explaining how to measure shell height, etc.
My own personal feeling is that torso height is much more relevant than overall height. Some manufacturers also realize that and will tell people that it's ok to disregard their stated height limit as long as there's sufficient shell left. Others are adamant that the standing height limit be followed, period, no matter what. I suspect cases like that are more of a legal CYA move, but without further details, I'm not one to tell people to ignore it.
What I'd love to see is a "do not exceed" line printed on the cover of the seat. Until your kid reaches that line, you're good. After that, it's outgrown.
My own personal feeling is that torso height is much more relevant than overall height. Some manufacturers also realize that and will tell people that it's ok to disregard their stated height limit as long as there's sufficient shell left. Others are adamant that the standing height limit be followed, period, no matter what. I suspect cases like that are more of a legal CYA move, but without further details, I'm not one to tell people to ignore it.
What I'd love to see is a "do not exceed" line printed on the cover of the seat. Until your kid reaches that line, you're good. After that, it's outgrown.
carseatcoach
Carseat Crankypants
I don't get it either.
Seat A may have been tested more extensively than Seat B.
Seat B may have passed extra testing that seat A failed.
Seat A's manufacturer may be more cautious than Seat B's.
Both manufacturers may be making wild guesses.
We don't know. And I'm not comfortable assuming I know more than the seat manufacturer does. I very well might, but I am not willing to bet my kid's life on it.
(My personal gut feeling is that some manufacturers are overly cautious, but again, I'm not willing to take that chance. There are plenty of other seats out there. And I do definitely deviate from recipes. I'm willing to take the risk that my brownies might come out a little funky. I'm not willing to risk my kid's seat failing catastrophically, even if there's only a very small chance that it could happen.)
Baylor
New member
That makes sense.. Im out of rep but will find you when im reloaded..
To be clear, im not saying it relevant, Im just trying to figure out why that rule?
I ponder things for a while and sometimes I can work it out or search enough here to find an answer, but this one stumps me.
Only knowing what I know that " do not exceed line" sounds like an awesome way to keep parents on the right track.
babyherder
Well-known member
I like the do not exceed line. Sounds perfect! i won't disregard overall height limits when rear facing. But I won't measure a kid every day if they're nearing the overall height limit but still have shell above their head. I'd measure them when its looks like they grew and if it turns out they're 40.5in in a 40in seat I'd either get a new seat or turn them. But I wouldn't stress that they rode that way.
Mercuria
Active member
I actually think it would be worse for all the weight to be in the torso (or, worse, head) than in the legs. It would raise the center of gravity and, consequently, put more torque on the shell.
That said, I can't guarantee the weight's not all in the feet (heavy boots?), which could fly up in an accident and cause the same effect. That could be even worse, since the legs tend to be longer than the torso. The manufacturer can't verify every weight distribution, so they set limits "on the safe side." At least that's my read on the situation.
That said, I can't guarantee the weight's not all in the feet (heavy boots?), which could fly up in an accident and cause the same effect. That could be even worse, since the legs tend to be longer than the torso. The manufacturer can't verify every weight distribution, so they set limits "on the safe side." At least that's my read on the situation.
In addition to Dorel's long stated 40" limit, Evenflo is now putting a 37" limit in the Triumph manual (and on the SureRide when it comes out, not sure about other seats). I say specifically in the manual because as it's explained to me, that's the only change. They've done testing and are more comfortable with that, but the seat hasn't changed and if your manual states the 1" only you may go by that.
I've asked both Dorel and Evenflo WHY. WHY does it matter overall height if the seat passes testing to 1" of shell (or in the case of many Dorel seats, head even with the top of the shell)? I've never gotten an answer beyond, "Do what your manual states" or "we're more comfortable with this." Which doesn't answer the question. And that's if I got a response at all. Though they're all happy to respond to me to tell me to do what the manual states.
I've not heard that the Evenflo change is retroactive. It'll just be out on new Triumphs, in their new manuals.
Wendy
I've asked both Dorel and Evenflo WHY. WHY does it matter overall height if the seat passes testing to 1" of shell (or in the case of many Dorel seats, head even with the top of the shell)? I've never gotten an answer beyond, "Do what your manual states" or "we're more comfortable with this." Which doesn't answer the question. And that's if I got a response at all. Though they're all happy to respond to me to tell me to do what the manual states.
I've not heard that the Evenflo change is retroactive. It'll just be out on new Triumphs, in their new manuals.
Wendy
aeormsby
New member
:yeahthat:
For some of the seats that go by a set height it could be possible that the additional weight high on the seat back could be causing too much rotation in an accident. Who knows.
A 'do not exceed' line would be ideal, but I wonder if the general public would understand the correct way to measure. There are plenty of posts here where even people who know about the 1" rule don't understand the correct way to measure that. (perpendicular to the seat back instead of parallel to the ground)
:yeahthat: I think it's probably this. We've been in the dark for years on height limits and it's frustrating to be told by engineer after engineer and manufacturer after manufacturer, "just follow what we say." It's like telling a kid to not put a knife in an outlet and not telling him why. He's gonna go do it to see what happens!
Leave it to our Canadian friends to scope it out for us: http://www.car-seat.org/showpost.php?p=2393232&postcount=64 . Rebound is affected by the height of a child. It makes perfect sense. We know this happens in an untethered ff seat with a tall child--the top of the seat is going to rotate very far forward. Same thing will happen in a rf seat. Now we have these gargantuan carseats that rf to 45 lbs that can hold really tall kids, so we do have to pay attention to their height and how they rebound.
But, I would like the straight talk on torso height vs. overall height. Britax does torso height, right? Experts for years have said overall height doesn't make sense, it's how the child fits in the seat.
Very curious about that as well. I´m waiting on the foonf and my son (2y7m) is RFing in a Recaro Proride still, and he´s very very tall for his age, he has passed the limit for standing height but he still has a little bit to go before the inch below the top limit. So, I don´t know what to do, leave him like this and wait for the foonf or turn him to FF until then. He is mostly legs and, yes they are tight on the recaro, but I still rather have him RF, it doesn´t make sense to turn if he still fits the chair, but it bugs me to go against the recommendations.
Harmony96
New member
I like that idea. Maybe with a little image of how the line is to not be exceeded, like all the little pictures on the seat of a shopping cart with how not to have a child in it.
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