How much safer is RF tethering (v. no RF tethering)?

[HappyMommy]

Hi,

I am trying to decide which convertible car seat to get and I am confused as to how important it is in terms of safety that I get a seat that allows RF tethering. People are telling me that they would never buy a RF seat that does not allow RF tethering but they do not really give me a good explanation as to why. I understand that RF tethering prevents rebound, but is rebound really that bad? Do kids really get injured during rebound? How much safer is it to tether RF in general?

Thanks!

 

[wendytthomas]

We don't know. It may not be. There are no studies that I know of comparing tethered to untethered in terms of safety. There is one study that I don't have a link for (does someone else?) that shows a benefit in side impacts. Otherwise we don't know if it's safer or not to tether.

Wendy

 

[Maedze]

You may hear such strong opinions on rear facing tethering, but in actuality, there is no reason for us to believe that it is 'safer' than just rear facing alone.

It certainly adds some stability to the install, but whether this translates to real-world numbers of fewer deaths or injuries, there just isn't any data to prove it.

What we do know, hands down, is that rear facing is safer than forward facing. Rear facing in an appropriately installed child restraint that the child fits in correctly is so very incredibly safe that anything else is just a little icing on a delicious, buttery cake

So the most important thing is to select a restraint that you will be able to use rear facing the LONGEST...regardless of whether or not it tethers

 

[DahliaRW]

ITA with Maedze. My ds2 is in a non-tethering rfing seat because it's the only seat that works in my car that he could be rfing in now. I wholeheartedly believe he's safer in that seat then in any ffing seat.

 

[KaysKidz]

In certain situations, a rf'ing tether would offer more protection then a non-tethered rf'ing seat...for instance...in an extra cab truck where the child would 'rebound' into glass. Umm...not my kid thank you very much!!

 

[amie815]

In certain situations, a rf'ing tether would offer more protection then a non-tethered rf'ing seat...for instance...in an extra cab truck where the child would 'rebound' into glass. Umm...not my kid thank you very much!!

Exactly what I was going to say and I got my info from Kay. We have an extended cab truck and out DD would definietly rebound head first into the window with out the tether. I personally think based on the laws of physics I prefer a seat with a tether versus without.

 

[catchthewind]

There is another thread around here that mentioned that rf tethering is potentially less safe for newborns. I personally prefer having an rf tether and all our convertibles have always had one, but one of the reasons we opted for the TF Premier for our newborn is because of the info on this thread. Not sure if it matters much since like others have said, rf-ing is so much safer in general, but it gives me a bit of peace of mind.
http://www.car-seat.org/showthread.php?t=60147

eta: That being said, my daughter is in a non-tethering seat until the TFP comes out here, and I have considered getting the regular tf for more cover options, but in the end I like the peace of mind I personally get from the tether/arb. I certainly don't lose sleep over the fact she's not in a rf tethered seat yet though.

 

[HappyMommy]

There is another thread around here that mentioned that rf tethering is potentially less safe for newborns. I personally prefer having an rf tether and all our convertibles have always had one, but one of the reasons we opted for the TF Premier for our newborn is because of the info on this thread. Not sure if it matters much since like others have said, rf-ing is so much safer in general, but it gives me a bit of peace of mind.
http://www.car-seat.org/showthread.php?t=60147

eta: That being said, my daughter is in a non-tethering seat until the TFP comes out here, and I have considered getting the regular tf for more cover options, but in the end I like the peace of mind I personally get from the tether/arb. I certainly don't lose sleep over the fact she's not in a rf tethered seat yet though.

Thanks for the link. Very interesting. I wonder if that's why Britax has infant seats with a rebound bar whereas their convertibles have RF tethers...maybe ARB is safer for newborns while RF tethers are better for older kids...who knows...

 

[Pixels]

Hi,

I am trying to decide which convertible car seat to get and I am confused as to how important it is in terms of safety that I get a seat that allows RF tethering. People are telling me that they would never buy a RF seat that does not allow RF tethering but they do not really give me a good explanation as to why. I understand that RF tethering prevents rebound, but is rebound really that bad? Do kids really get injured during rebound? How much safer is it to tether RF in general?

Thanks!

Rebound isn't really that bad. If it was, we'd see rebound control on more seats and/or federal regulation to take care of the problem.

Kids might get injured during rebound, but if they do, it's minor injuries, similar to a trip and fall on the sidewalk, and that only happens in the most severe crashes.

We don't know how much safer it is to RF tether, if it is safer at all. There's one study that speculates that it would be safer in side impacts, but found only a small difference in frontal impact. Also, that study isn't of much use to us because of problems with methodology.

That study looked at a Britax, an Evenflo, and a Safety 1st seat. Evenflo and Safety 1st don't allow nor have they ever allowed RF tethering. The study used the RF tether to increase the recline angle on all the seats, which used to be but is no longer allowed with Britax. (In fairness to the study authors, it may have been allowed at the time.) They did not look at the Radian, which does allow using the tether to adjust the recline angle, but usually doesn't need that to achieve the 40 degree angle they used in the study. (Again, in fairness to the study authors, I'm not sure the Radian was out at the time. I don't see a date anywhere on the paper.)

When they installed the non-tethered seats, they used a chunk of pool noodle, then tightened the LATCH belt to get a certain angle. In using this method, they neglected to make any observation about the LATCH tightness. Was it tightened to a certain tension, as FMVSS 213 requires for its testing? Was it tightened to the one inch rule, as required by the carseat owners manuals? We don't know. Maybe it was, maybe it wasn't. When they installed the tethered seats, they installed "as tightly as possible" while making sure to achieve their goal recline angle.

They did tether all of the seats, even the "non-tethered" seats. The "non-tethered" seats were tethered with an add-on tether under no tension pre-crash, to prevent the dummy from striking the seat back. Therefore, this study isn't a comparison of tethered vs non-tethered seats, it's a comparison of seats that were tightly tethered with no pool noodle vs loosely tethered with a pool noodle. I'm not surprised that there were only small differences in performance.

In certain situations, a rf'ing tether would offer more protection then a non-tethered rf'ing seat...for instance...in an extra cab truck where the child would 'rebound' into glass. Umm...not my kid thank you very much!!

That's only a theoretical risk. You don't have any hard evidence to show that rebounding into glass is any more dangerous than rebound in general, do you? If so, I'd like to see it.

 

[HappyMommy]

Thanks for the clarification about the study, Melissa. I wonder why they would tether seats that are not meant to be tethered to begin with-bizarre. Are you suggesting that using a pool noodle is not as safe as not using a pool noodle (as when you have a seat that does not require pool noodles to achieve the proper recline)?

 

[Admin]

Thanks for the link. Very interesting. I wonder if that's why Britax has infant seats with a rebound bar whereas their convertibles have RF tethers...maybe ARB is safer for newborns while RF tethers are better for older kids...who knows...

There is also less chance of misuse with an anti-rebound bar.

In general, the better coupled the passenger is to the vehicle, the greater the benefit they get from riding down the crash forces more gradually while the vehicle frame is crushing. So, the more points of restraint the child has to the child seat and the child seat has to the vehicle, the better. Of course, there can always be exceptions.

Rear-facing is inherently very safe. Properly installed and used correctly, just about any rear-facing seat is going to cut any risks to the child to nearly zero. Choosing among brands, models, features, seating positions and other issues may make a slight improvement, but probably not enough to make a difference.

I appreciate RF tethers, but I wouldn't buy or not buy a seat solely for this feature. I have seen case studies of minor injuries suspected to be the result of rebound into a vehicle seat or pillar, but I have not seen any conclusive studies that these occur with any frequency. The same is true of the comments about newborns or small infants using a RF tether. There were some studies done using test sleds that found an increase in forces during rebound, but no indication that this possible increase is resulting in any injuries. It's all theoretical at this point.

 

[Suzanne74]

This may seem like a really dumb question but does a carseat like the Graco Snugride have or not have rebound? I know it isn't tethered but since it snaps into a whole base vs a convertible snaping into latches/seatbelts with some movement I am not sure how that "rebound" works.

 

[Maedze]

This may seem like a really dumb question but does a carseat like the Graco Snugride have or not have rebound? I know it isn't tethered but since it snaps into a whole base vs a convertible snaping into latches/seatbelts with some movement I am not sure how that "rebound" works.

Yes, all rear facing seats have some rebound. Rear facing tethered seats have the least, followed by seats with an anti-rebound bar.

Infant seats have a great deal of rebound due to their design.

There is a theory that having the handle in the upright position provides some rebound protection.

 

[jenfrogmom]

Would it be safe to have an infant in a convertable or an infant seat? We have a Keyfit and an XTSL. Should I be moving the baby out of the keyfit?

 

[Jeanum]

Either is safe provided that the baby fits the carseat and you can achieve a proper installation with less than 1 inch of movement at the carseat's belt path in your car. Rear facing in and of itself is the safest way to travel.

 

[KaysKidz]

That's only a theoretical risk. You don't have any hard evidence to show that rebounding into glass is any more dangerous than rebound in general, do you? If so, I'd like to see it.

Rebounding into glass simply isn't safe, period. At least w/rebounding into a seat, they are hitting something with some give. Do I have any 'evidence'? No, not stastical proof. But there is a little thing called common sense. I do not like rebounding in general, but rebounding into glass will not happen on my watch.

Rebounding is not a desired effect. It's simply an accepted 'side effect' of the rear facing seat. And while I'm not an engineer, it's not a side effect that I'm willing to risk with my children, and I will use a seat that can reduce the amount of rebound they may experience in a collision.

 

[Pixels]

Thanks for the clarification about the study, Melissa. I wonder why they would tether seats that are not meant to be tethered to begin with-bizarre. Are you suggesting that using a pool noodle is not as safe as not using a pool noodle (as when you have a seat that does not require pool noodles to achieve the proper recline)?

If you don't need a noodle to get the proper recline, don't use it. It's unnecessary, so why mess with it? Pool noodles are only used to achieve proper recline.

When they installed the non-tethered seat, the only way they had to increase recline was to use noodles. It's an accepted method, but they appear to have done it with every seat regardless of whether it was needed or not. Then they used tension on the LATCH strap to make the seat more upright until it was exactly at 40 degrees, rather than installing the seats at a consistent install tightness (consistent tension on the LATCH strap, or one inch of movement rule) and allowing the seat to be anywhere in the acceptable recline range, or working a bit harder and getting both a consistent LATCH tightness and matching initial recline angles.

They tethered seats that are not meant to be tethered because there just aren't that many that allow it (essentially one Britax, since they're all variations on the same seat, and possibly the Radian if it was out). They were trying to figure out if RF tethering is a good thing or a bad thing, something that carseat manufacturers should take into consideration.

 

[HappyMommy]

Melissa-Thanks. I understand that you would not use a pool noodle if you did not need one to achieve recline. I get your comments about the fact that the methodology used during the study is questionable. I guess, beyond what they did during the study, my question is: if you have the choice between buying a seat that would likely need a pool noodle to achieve proper recline versus a seat that propably does not require a pool noodle, would you buy the one that does not require a pool noodle b/c it is likely safer? What are your thoughts on that? Thanks!

 

[wendytthomas]

Using a pool noodle is proper practice, it's not safer or less safe. I think every seat from Dorel's $45 Scenera to Britax's $380 Advocate ok the use of a towel or pool noodle to achieve the appropriate angle.

When Piper was a baby Britax was fine with using the tether to change the angle. Now they're not. My car has super sloped backseats. I used five pool noodles to get Laine's TFP to a 45º angle. I was fine with that as well. Now at seven months she has one noodle under there.

Wendy

 

[Pixels]

Noodle needed or not doesn't phase me one way or another. Sometimes it can be more difficult to get a proper install with noodles, but as long as the install is good, it's good.