Convertible car seats are a great solution to the long-term car seat needs of any family. Look for top safety ratings, a comfortable ride, ease of installation and a seat that fits your car and your child's size to find the perfect convertible car seat.
All Britax seats, including the Marathon 70 (*Est. $290), the Marathon Classic (*Est. $200), the Boulevard 70 (*Est. $320) and 70 CS (*Est. $340), the Advocate 70 CS (*Est. $380), the Roundabout 55 (*Est. $200), and the Roundabout 50 Classic (*Est. $270) get top marks in crash tests conducted by independent review organizations. Also receiving top ratings are The First Years True Fit Recline (*Est. $170) and premier (*Est. $240) and the Safety 1st Complete Air 65 (*Est$180). Each of these seats meets or exceeds all applicable federal safety standards.
Where the top seats stand out is in side impact protection that goes beyond federal safety standards. Designed to prevent intrusion of objects and also to absorb impact forces to the child, side impact protection is typically built into car seats through deeper, hard-shell wings with impact absorbing foam. Britax is a leader in this safety feature. All of their seats feature side-impact protection with dense, high-quality expanded polystyrene (EPS) foam. The True Fit Recline and Premier also have side impact protection built into the seat, but it is not as dense as the Britax models. The Britax Advocate 70 CS and Boulevard 70/70CS have height-adjustable, head-stabilizing wings that prevent side-to-side motion of the head. The Advocate includes air-filled cushions on the outside of the seat to absorb more impact and also protect other rear seat passengers. However, more than one reviewer comments that this extra padding adds too much bulk to an already large seat.
The most innovative take on side impact protection comes in the form of air technology featured in the Safety 1st Complete Air 65 and, to a lesser extent, in the Safety 1st onSide Air (reviewed in our convertible seats under $150 section). This technology places large air cushions around the child's head and sides that buffer the head from impact intrusion and release air during a crash to disperse impact force.
Another safety factor addressed in top seats is child stabilization within the seat. The Britax Marathon 70, Roundabout 55, Boulevard 70/70CS, and Advocate 70 CS feature plastic frames with integrated steel bars to reduce flexing in the seat and prevent forward movement of the child. To further reduce child movement in a crash, the Britax seats named above have cells built into the seat bases that compress in a crash, lowering the child's center of gravity and reducing his or her forward motion. All Britax seats have impact-absorbing top tethers that stabilize the car seat in the forward- and rear-facing positions. The First Years True Fit Recline does not have rear-facing stabilization, but the First Years True Fit Premier has an anti-rebound bar that works to prevent movement in the seat when rear-facing.
Safety agencies including the NHTSA acknowledge that ease of use is extremely important in evaluating car seat safety. An improperly installed car seat will not be safe, so ease of use is an important consideration when choosing a car seat.
The seats that score the highest marks for good, clear directions are the seats in the Britax line as well as the First Years True Fit Premier and Recline. In general, the manuals for those brands are written in a clear and concise manner. However, Britax receives low scores from the NHTSA for labeling on the seat, which means that if you leave the manual behind and have to reinstall the seat at Grandma's, you may have some difficulty. This may be complicated by the fact that you need the manufacture date to view an installation video or download user guides from the website. The True Fit seats, by contrast, receive top marks for labeling.
All of the Britax seats, the Safety 1st Complete Air 65 and True Fit Premier and Recline seats have push-button style LATCH connecters to secure and remove the tethers to the anchors easily. All Britax seats, with the exception of the Roundabout 50 Classic, feature built in lock offs that are designed to maintain seat belt tension around the seat while it is installed. The Safety 1st Complete Air 65 and the True Fit Recline and Premier also have these lock offs. In addition, the True Fit Recline and Premier have removable headrests to make rear-facing installation easier, but the seats should not be used without the headrest once the child reaches 22 pounds.
While parents and reviewers love the safety of side impact protection, some of the more aggressively protected seats may pose challenges to loading and unloading kids, particularly in the rear-facing position. The seats that garner this criticism most frequently include the Britax Boulevard 70 and 70 CS, the Britax Advocate 70 CS and the Safety 1st Complete Air 65, thanks to their additional side-wing protection and overall bulk.
Harness height adjustment is a big topic among reviewers and parents alike. It's a benchmark that distinguishes the best car seats for reviewers and for which parents seem willing to pay more. The best seats have at least four harness height adjustment points to accommodate growing children, and the seats included in this review have four or more. The easiest harness to use is one that can be adjusted for height from the front, without uninstalling the seat and re-threading the harness straps through the back. The Britax Marathon 70, Boulevard 70 and 70CS, and Advocate 70CS all boast no-rethread, front adjustable harness heights. The harness height can also be adjusted from the front on the True Fit Premier and Recline, and on the Safety 1st Complete Air 65.
A cut above the rest, the Britax Boulevard models and the Advocate allow for a perfect custom fit with a roller design that sets the height exactly at the child's shoulders -- from the front.
The harness tension should also be adjustable from the front of the seat to ensure a snug fit. While all car seats in this review have this feature, it works better on some than others. For the most part, Britax seats get high marks for their quality harnesses that move easily through the adjuster. The Britax Boulevard 70 CS and the Advocate 70 CS make an audible click when the harness has reached a correct tension level. However, parents say this mechanism clicks before the harness is tight enough, and expert reviewers worry that this feature will cause parents to be less attentive to manually ensuring that the harness is properly secured.
In addition to the upper harness restraints, the best car seats have an adjustable lower crotch strap that can be moved outward as the child grows. This feature is particularly important in the seats with higher weight ratings that carry larger children. The best reviewed Britax Marathon 70 is commended for not only its position-adjustable crotch strap, but also for the crotch strap's overall length, which makes it easier to secure the child more comfortably, even when small. The First Years True Fit seats and the Safety 1st Complete Air 65 seats also have adjustable crotch straps.
Cleaning the seat cover is an important consideration for long-term car seat use, especially for families with a child prone to motion sickness. Britax seats have one-piece covers that are generally easy to remove, and the harness also can be removed for cleaning. The Britax Marathon 70's harness can be removed while the seat is installed in the car -- an obvious plus that reviewers and parents comment on. However, not all Britax covers are machine washable due to different fabric types, so it is worthwhile to check the fabric style before making a purchase. All the foam on the nice, plush seats will also absorb liquid spills, and, while the seat covers often can be washed in the machine, the foam usually has to be hand washed. The First Years True Fit Premier and Recline also have easy-to-remove, machine washable covers.
Convertible car seats can be a one-time, long-term purchase for your child's car seat needs, but only if the weight ratings on the car seat are high enough to take a child to the recommended upper weight rating of 35 to 40 pounds (rear-facing) and 40 to 80 pounds (front-facing). The Britax Marathon 70, Boulevard 70/70CS and Advocate 70CS all offer rear-facing weight ratings of up to 40 pounds and front-facing weight ratings of 70 pounds. However Britax has a height rating of 49 inches (except for the Roundabout 55 which is 46 inches), and some parents say that their children will outgrow the seat height long before they reach the top weight rating.
The Safety 1st Complete Air 65 and True Fit Recline and Premier seats provide the weight ratings for long term use with maximum forward facing weight limits of 65 pounds. The Safety 1st Complete Air 65 has a rear-facing weight rating of 40 pounds, but it allows taller children to ride longer with a 52-inch height limit. The True Fit Recline and Premier have height ratings of 50 inches, but they only allow children to ride rear-facing until they are 35 pounds.
One of the most important considerations when choosing a car seat is making sure it fits in your car. This includes the space the seat will take up across the width of the back seat and the space the seat will take up front to back between the back seat rest and the front seat rest. While most car seats will fit in any car in the forward-facing position, rear-facing installation always requires more front to back space due to the recline angle of the seat. Most manufacturers give measurements on their websites to help determine if a car seat will fit your model of car. Also see our recommendations for compact convertible car seats for more detailed recommendations.
Britax car seats are among the bulkiest, and the Safety 1st Complete Air 65 also doesn't fit in some cars due to bulk. One notable feature on the True Fit Recline and Premier convertible car seats is their removable headrest feature. This feature is designed to both make rear-facing installation easier and to allow parents to use the seat without the longer headrest until the child reaches its 22 pound weight limit. However, this feature has led to some confusion among buyers who get the mistaken impression that it is a compact car seat. We read a number of reviews from parents who expressed frustration when they realized that the seats are too long for their car with the headrest in place. If you intend to use this seat in the rear-facing position, it is recommended that you check the measurements with the headrest on.
The Combi Coccoro (*Est. $200) Diono RadianRXT (*Est. $340), the Cosco Scenera (*Est. $55) and the Graco ComfortSport (*Est. $90) are the models that are best known for their compact fit. All four models are discussed further in our section on compact car seats.
Child comfort is another important lifestyle consideration, especially if you spend a lot of time in the car or take long trips. Britax seats are universally admired for their plush padding. The wider Britax side wings are nap-friendly and the seats recline in the forward and rear-facing positions. If you're going to log serious miles with a car seat, having a model that reclines is a definite advantage. As one parent notes, there is "nothing more unsettling than looking into the back seat and seeing your child's head drooping to hit their chin."
True Fit's Premier and Recline offer a reclining feature in both the front- and rear-facing positions, and they have nicely placed armrests and deep side wings. The Safety 1st Complete Air 65 reclines, but there are complaints about the difficulty of getting the recline angle right in the rear-facing position.
One caveat in the area of comfort: Some parents find that some seats are too well padded. The Boulevard 70 and 70 CS, Advocate 70 CS, and Safety 1st Complete Air 65 are all equipped with side impact protection wings that buffer the face and head. Some children like this extra pillow, but it may obstruct their view and frustrate them, particularly as they get older.
Britax seats do not come with cup holders, but they can be purchased separately (*Est. $15). The Safety 1st Complete Air 65 come with a removable cup holder, and the True Fit Premier and Recline have built-in cup holders. Because of their heft, convertible car seats are not the easiest to use for travel or to use in multiple vehicles. Smaller car seats are easier to carry. Britax does sell a car seat travel cart (*Est. $80) that allows you to wheel the relatively bulky seat through airports. Nonbrand specific travel carts also allow you to wheel more bulky car seats.
All the convertible car seats in this report offer a one-year warranty. Like most car seats, these seats expire six to eight years from the date of manufacture and should not be used after that time. All of the manufacturers mentioned in this report have websites that are generally well laid out and easy to navigate, but to download a manual for the Safety 1st seats you have to have both the product number and the date of manufacture. To download a Britax manual, you have to have the date of manufacture. This is an inconvenience if the seat's already installed. True Fit manuals are easily downloaded from the website without any additional information.
The Britax Marathon 70 is our pick for best convertible car seat. The Marathon 70 offers the best overall combination of safety features, ease of use, lifestyle features and customer service. In addition to high safety ratings and superior side impact protection, it has all the convenience features that make a car seat one less hassle for parents. It's expensive, but it can be used until a child has reached the upper limit for weight of 70 pounds, making it one-time investment that likely will last as long as your child needs a car seat.