Outgrowing Birtax Decathlon?

I have to start out by saying this is my first post, so please forgive me if I’m not up on the lingo.

My daughter turned 3 over the summer and I’m afraid she is starting to outgrow her Britax Decathlon. She has held a weight between 34 and 36 pounds for the past 20+ months. She is getting tall though, 41 inches. I think the seat goes up to 48”, but her head seems like it is very close to the top of the shell. If anyone could post a picture of an older/taller child FF in a Decathlon or Marathon so I can get a comparison I would greatly appreciate it. I just can’t imagine her head being higher than the seat; is that really right?

I currently have 3 decathlons FF in different cars. Should I start looking for a new seat within the next few months? And if so what are the differences between the Frontier and the Nautilus? I love Britax, but have seen a lot of bad reviews of the Frontier online. If you have any other suggestions for a taller child I would love to hear it. I would like to say it is the last seat I would buy for her, but if a convertible (not 3-in-1) would be safer for now, I’m not completely opposed to buying a booster only in 4ish years. She is my only child and I don’t foresee any others coming along anytime soon, so I’m not worried about passing seats down to siblings or size for positioning in a car.

She should still fit in it. My DS is just at the point of outgrowing the Decathlon at 46in and 52lbs. My DD is 38in and 35lbs and she has some growing room.

Your DD is definitely below the weight limit of the seat. Most kids won't get to 65lbs in the seat - as you can see from my DS's stats.

Look at where her shoulders hit in relation to the straps. The straps must be AT or ABOVE her shoulders. My DS is at the point that his shoulders are just below the harness straps. Look at how much space she has above her shoulders and that will give you an indication about how much growing room she has.

The last way that seats are outgrown is because the top of the child's ears go above the hard shell. Every passenger should have head support behind their heads to the top of their ears - which is something I didn't learn until I started to learn about car seats! If her head is just getting near the top of the car seat, then she definitely has growing room.

HTH

Jan06twinmom is right. Check her shoulders where the harness falls and see if its at the right height, then check her head. the top of her ears should not exceed the top of the car seat shell.

Frontier VS nauti...
Frontier can be hard to install, but sometimes it's an awesome fit! What kind of car do you have? do you live close to a Babies R us? They carry the frontier and the nautilus so you can try both out in your car.

For your daughter, since she is only forward facing-never to be RF again, I would recommend a combination seat (like the front and nauti) which is a harness and booster combination. A convertible car seat can go RF and FF and can also have a booster portion like a 3-in-1.
It's up to you, she still has growing room in her decath

in this pic of my boys, Levi is 6 and 40lbs (on the right), but he's pretty tall. he is sleeping, but you can see his head has gone over the shell, but his ears are still below.

A forward facing seat is outgrown if any of the following happens: The weight limit is reached, the tops of the shoulders go above the top strap slot, or the tips of the ears go above the top of the seat shell, whichever comes first. Most kids will outgrow a bigger britax seat somewhere around 42-48 inches and around 45-50 pounds, on average (there was a poll some time ago)

Here is my dd at 25 months, just after I flipped her forward facing.

SHe lasted a little more than a year more in it, to about 39 months (40 inches, 40 pounds).
And here is my other dd when she hit the harness height of her marathon (42 inches, 42 pounds)

Both my girls have longer torsos, and I found the the decathlon strap height is just a tad taller then the marathon.

Thank you so much for the replies! It just looks so weird seeing her head at the top of the shell… I remember when I first put her in it at 5months, thinking she will never fill this seat. I think I just looked in the mirror one day and she was grown.

My daughter goes between my car and my parents cars frequently, so a 1999 Pontiac Grand Am, 2005 Toyota Camry, and a 2007 Honda Accord.

Today I am going to help a friend today install a Graco Nautilus in her Honda Odyssey for her daughter; that will be my first interaction with it. I might stick it in my car just to see how it fits. I know the quality of the straps between the Graco Comfort Sport and the Britax are very different; I’ve always loved the straps of my Britax. Does the Nautilus have the same straps as the other Graco car seats? Are the seats pretty much equal just depending on which installs better? If I do switch to either of those how much longer (height wise) should I expect to have her in a harness?

The Nautilus, based on purely subjective criteria , is a much better forward facing seat than the Decathalon.

It's more spacious. It's lower profile instead of sticking a big kid up onto the ceiling of the car.

It will last 18 months to two years longer in a harness. The harness adjuster is a DREAM and is so, so, so much better than the Decathalon. The harness itself never tangles.

It's easy for a big kid to adjust himself. My five year old can buckle himself up, tighten it correctly, and loosen it and let himself out, easily and quickly. He can't do that on other seats.

It comes with the best cupholder I've ever seen on a child restraint, and super-cool 'cubbies' for treasures

That being said, my current choice for a just turned three year old would be a rear facing convertible with a higher rear facing weight limit

HEe hee, here is dd in a nautilus, in the same seating position, at about 27 months

SHe was on the third slot.