How to Install a Convertible Car Seat Rear-Facing

What makes a convertible seat different when rear-facing

An infant seat usually clicks into a base that stays in the car. A convertible seat has no detachable carrier. The whole seat stays installed and is used rear-facing first, then turned forward-facing later. Rear-facing, a convertible seat has its own belt path, usually under or behind the child's leg area. This is separate from the forward-facing belt path, and many seats label the two with different colors. Convertible seats are also larger. In smaller vehicles, the seat can push against the front seat or need a particular recline angle to fit.

US safety guidance recommends keeping children rear-facing as long as possible, until they reach the highest rear-facing height or weight limit the seat allows. Those limits are printed on the seat's labels and in its manual, and they vary by model.

Before you start

Read the car seat manual and the child restraint section of your vehicle owner's manual. Together they tell you which seating positions are approved and where the anchors are. Check the seat's labels for the rear-facing height and weight limits and the lower anchor weight limit. Find the rear-facing belt path on the car seat. Using the forward-facing path while rear-facing is a common and serious mistake. Decide where the seat will go. Never put a rear-facing seat in front of an active front airbag. The back seat is the recommended location.

Choosing a seating position

The center rear seat is often described as the position farthest from a side impact. It only works if you can get a secure installation there. Many vehicles have no dedicated lower anchors in the center. Some do not allow "borrowing" the inner anchors from the outboard seats, while others permit it. If the center has no approved lower anchors, a seat belt installation is usually the way to use it. If the seat will not install tightly in the center, a secure outboard installation is the better choice. Also check that there is enough room for front occupants and that the car seat isn't wedged against the front seatback in a way its manual prohibits. Some seats allow light contact with the front seat and others do not.

Lower anchors or seat belt: which to use

Both methods are considered equally safe when done correctly. Pick whichever gives you a tight installation in your vehicle. Using both at the same time is generally not allowed unless the seat maker specifically says it is.

Factor | Lower anchors (LATCH) | Vehicle seat belt; How it attaches | Connectors on the car seat clip to metal bars in the seat bight | Lap and shoulder belt routed through the rear-facing belt path; Weight limit | Has a combined child-plus-seat limit; switch to the seat belt once it's exceeded | Usable up to the seat's rear-facing limits; Availability | Usually outboard positions; center varies by vehicle | Available in most seating positions; Locking | Not needed | Belt must be locked by the retractor or the seat's lock-off; Common issues | Hard-to-reach anchors, twisted straps | Unlocked belt, twisted webbing, buckle stalk in the belt path

Step-by-step rear-facing installation

1) Set the seat to rear-facing mode. Move any recline foot, base or adjuster to the rear-facing position the manual specifies for your child's age or weight. 2) Place the seat rear-facing on the vehicle seat and check the recline indicator. This may be a bubble, line, ball or color window. Adjust the recline until the indicator reads correctly for your child. 3) Route the lower anchor strap or the seat belt through the rear-facing belt path only. Keep the webbing flat and untwisted. 4) If using lower anchors, attach both connectors to the vehicle's anchor bars and confirm they're latched. 5) If using the seat belt, buckle it and lock it. Most US vehicles let you pull the shoulder belt all the way out to switch the retractor into locking mode, which ratchets as it retracts. If the seat has a built-in lock-off, the manual may tell you to use that instead. 6) Tighten. Press down firmly into the seat near the belt path with a hand or knee, then pull the strap or belt tight while feeding slack back toward the retractor or tightener. Some seats have a tensioning panel or tightening mechanism that does most of this work. 7) Recheck the recline indicator. Tightening can change the angle. 8) Test for movement at the belt path, as described below.

Checking that the seat is tight enough

Hold the car seat at the belt path, where the anchor strap or seat belt passes through, and tug side to side and front to back. The common guideline is that the seat should move less than one inch in any direction at that point. Don't test by shaking the top of a rear-facing seat. The upper end naturally moves more, and that is expected. If the seat moves too much, release the tension, press it down harder and tighten again. If it still won't get tight, try the other installation method or a different seating position.

Top tether and other anti-rotation features

The top tether is a strap from the top of the car seat to an anchor in the vehicle. In the US it's mainly used forward-facing. Most convertible seats don't use the tether rear-facing, though some models allow or require a specific rear-facing tether setup. Some seats have other features meant to reduce rotation in a crash, such as anti-rebound bars or load legs. Use these only as described in that seat's manual. A load leg in particular may not be compatible with every vehicle floor or seating position.

Getting harness fit right

A well-installed seat still needs the child properly harnessed. Rear-facing harness fit follows a few widely used rules.

Harness straps should come from slots at or just below the child's shoulders when rear-facing. Many seats use a no-rethread headrest that adjusts the strap height automatically. The chest clip should sit at armpit level, not down on the belly or up at the neck. Tighten the harness until you can't pinch any slack in the webbing at the collarbone. This is often called the pinch test. Keep straps flat and untwisted, and buckle the crotch strap in the position the manual specifies. Avoid bulky coats or aftermarket padding under the harness. They compress in a crash and leave the harness loose. Use a blanket over the buckled harness instead. Check the head position. Most seats require a minimum gap between the top of the child's head and the top of the shell or headrest. The amount is set by each manufacturer.

Common rear-facing installation mistakes

Routing the belt or strap through the forward-facing belt path. Leaving the seat belt unlocked, so the seat loosens over time. Using lower anchors after the child and seat exceed the lower anchor limit. Using lower anchors and the seat belt together without manufacturer approval. Ignoring the recline indicator, especially with newborns who need more recline to keep the airway open. Placing the seat in front of an active airbag. Turning the child forward-facing before they reach the seat's rear-facing limits.

When to get a hands-on check

If the seat won't tighten, the recline won't sit in range, or the manuals seem to conflict, a certified Child Passenger Safety Technician (CPST) can inspect the installation and show you how to do it yourself. Many fire departments, hospitals and community safety programs host car seat checks. Recheck the installation from time to time, after moving the seat to another vehicle, and whenever your child grows enough to need harness adjustments.