Looking for a car seat for a kid who’s at the top end of the growth chart? The limits vary greatly in convertible car seats available today.
There is no age limit for a seat; only height and weight limits.
Convertible Car Seat or Booster Seat?
First, let’s figure out which type of seat is the best to go with.
Convertible car seats get their name by being able to convert from rear facing to front facing.
Ideally, children remain rear-facing until they reach the weight limit of their seat. Once kids no longer fit rear-facing, you have more options.
Convertible seats can be installed facing forward, where the weight limit is higher than in the rear-facing position.
- If you have an infant seat that your child is outgrowing, you will most likely want to go with a convertible car seat so your child can remain rear-facing longer.
- If your child is ready to be forward facing, consider a booster seat.
Now, you might think of a booster seat as a small platform that a kid sits on to raise their height. Those types of boosters are really only for older kids. Booster seats are also available with a high-back and a 5-point harness. In a way, these seats are convertible since they can either be used with a 5-point harness or with the vehicle’s seat belt once a child is tall enough.
If your child has outgrown their rear-facing convertible seat you might consider moving to a booster seat.
One reason why you might do this is if you’re planning to hand the seat down to your younger child. Or, you may prefer a more upright seat with more cupholders, storage, and room to grow.
If a booster seat sounds right for you, they do allow for higher height and weight limits.
Which Convertible Car Seats have the Highest Weight Limits?
While you won’t find a convertible seat that will go up to 100 pounds, the Maxi Cosi Pria 85 has the highest limit at 85 pounds.
Here’s what’s good and not so good about the Pria 85.
The weight limit is 40 pounds rear facing, which is pretty typical. The forward-facing weight limit is of course great at 85 pounds.
The height limit is 52.” While this is a pretty good max height, and a few inches taller than popular Britax seats, it’s not the best. If you have a child who is in a high percentile for weight but more average for height, this is a great choice.
If your child is at the top of the growth chart for both weight AND height, definitely go with the Diono Radian RXT.
The RXT has an excellent 45 pound rear-facing weight limit and is good for 80 pounds forward-facing. The height limit is also the best out there by far at 57″. This is a great seat all around and I highly recommend it.
What if I Need a Seat for 100 Pounds and Beyond?
In this case, you’ll need to look at a booster seat.
Until your child is both 4’9″ or taller and at least 8 years of age, it’s important to use a booster to get to the proper height.
5-point harnesses are safer than the 3-point seat belts installed in cars. When possible, I recommend using a high-back booster with 5-point harness over a backless booster.
Typically, the 5-point harness on a booster seat can be used up to 65-90 pounds depending on the model. Once your child reaches that limit, you can continue using the seat along with the vehicle’s seat belt.
Something that doesn’t get discussed often is how much safer a 5-point system can be for kids who have a hard time sitting still in the car. With a 3-point seat belt, the slack in the belt makes it very easy for a kid to wiggle out of position. If the shoulder belt ends up under their arm or across their neck, safety is compromised. A booster in harness mode has no slack in the belts. When used properly, wiggly children can’t move into an unsafe position.
Here are my recommendations for 5-point harness booster seats with over 100 pound weight limits.
For the highest weight limit in a harnessed model and very easy installation, look to the Britax Frontier Clicktight. As an owner of this seat, all of my research pointed me here.
The Frontier Clicktight can be used with the 5-point harness for up to 90 pounds, which is far higher than most models. The seat can be used along with the vehicle’s belt up to 120 lbs. With such high limits, this could be the last seat you’ll need to buy for your kid.
The Clicktight system makes it incredibly easy to install properly. This makes it very convenient for travel. On our last trip, it only took a couple of minutes to install in the rental car. After a long day of air travel, this was a very welcome time-saver.
The Frontier is so good that I have a hard time recommending any other seat over it. If you’d like to check around on your own, here’s a rundown of some of the other models available:
- Chicco MyFit Harness + Booster (65 lb. harness limit; 100 lb. seat limit)
- Graco Tranzitions 3-in-1 Harness Booster Convertible Car Seat (65 lb. harness limit; 100 lb. seat limit)
- Evenflo Transitions 3-in-1 Combination Booster Seat (65 lb. harness limit; 120 lb. seat limit)
What if My Child is Already Beyond the 5-Point Harness Weight Limit?
In this case, a belt positioning booster seat will suffice.
You have two options – either a high-back booster or a backless booster.
The high-back booster offers a couple of benefits. First is head support. Some cars have no rear headrests. Those that do can’t always be positioned properly to the midpoint of the child’s head. Another benefit of high-back boosters is the “wings” at the top which provide side impact protection for the child’s head.
For these reasons, high-back boosters will always be safer than backless.
With that in mind, a backless booster is better than no booster at all for any child under 4’9″ in height.
Which of the above recommendations you should go with depends on your child’s current weight and how long you’d like to use the seat.
Have a child approaching the forward-facing limit of their current seat? I recommend going with a high-back booster. In particular, the Britax Frontier Clicktight is an excellent choice.