Child car seats: What is a Top Tether?

Even ISOFIX seats must be held fast by a top tether in Australia, but what is it – and how does it work?

When you are expecting your first baby, there are a lot of new lessons to be learned. One of the biggest ones is the baby seat, how it works and how to install it in your car. That’s when you’re likely to hear about top tethers for the first time.

In Australia, all baby seats must be attached to the car using two methods; the first is a top tether (a strap) and the second is either ISOFIX or the car’s seatbelt.

Top tethers were introduced to Australia in the 1970s and made mandatory as the safest method of securing the top of a child seat to a vehicle. They are designed to restrain the top portion of the child seat and stop it from tipping forward or rotating during a crash.

The top tether is a flexible webbing strap that is attached at the top/back of a child seat. At the other end of the top tether, a metal hook clips onto a top-tether anchor point installed in your vehicle.

Australian child seat manufacturer Infasecure says: “The top tether strap significantly reduces the forward movement of a child (and their restraint) in the event of an accident, and as a result reduces a child’s risk for injury, especially to the head. Correct use of the top tether strap can also help mitigate the effects of other installation mistakes, such as a loose harness or a loose seat installation.”

Top tethers can vary slightly in their position from child seat to child seat, depending on the manufacturer and the category of seat.

Most commonly, they are fixed behind the backrest of the child seat (left of the image) but for some brands, they are located up top, at the back of a child seat when it is in the forward-facing position (right of the image). But their job remains the same in either case.

The top-tether anchor point is the location where the top tether on the child car seat is anchored to the vehicle. These are usually metal anchor points that are engineered for the car and installed during the manufacturing process.

They can vary in appearance and location from vehicle to vehicle, and it’s important to consult your car’s manual to locate them so you do not mistake other anchorage points that look similar (such as for luggage).

In most new cars, the top-tether anchor points are within plastic guides and clearly labelled.

Sometimes, they are not labelled.

Sometimes they are hidden behind the seat back fabric and little woven labels tell you they are there.

Top tether anchor points can be positioned in different places in your vehicle, too. Most commonly, they are on the seatbacks.

Or in the ceiling.

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Or in the boot floor.

It is no wonder that time-poor parents find installing baby seats confusing, and top tethers are often installed incorrectly. It’s important to find the time, however, as your child’s life could literally depend on the top tether being installed correctly.

Although top-tether anchor points are usually clearly labelled and easily identified, in some vehicles they look just like a metal bar (or in some dual-cab utes, a webbing loop). You need to read your vehicle’s manual to find your top-tether anchor points and child seat installation instructions. If in doubt, talk to a qualified child seat fitter.

Once you have located the correct top tether anchor point, clip the metal hook on it and then tighten the top tether strap using the adjuster. The strap should be taut but not overtight, or the child seat could lift off the vehicle’s seat.

You must ensure your top tether is not overly twisted, as twists can create weak points (up to one twist is permitted).

Sometimes the strap on your child seat is not long enough to reach the top-tether anchor point. This is most commonly found in the case of rear-facing child seats. To overcome this, you need a top-tether extension strap.

The unused length of strap should be rolled up and fastened away with the supplied Velcro tab, or most child seats have a little bag/pocket to tuck it into. This is so it doesn’t fly around and hit passengers in the face in an accident.

It is currently mandatory in Australia (ADR34) for all passenger vehicles to be sold with top-tether anchor points in all second-row seating positions.

For commercial light goods vehicles, including dual-cab utes, child restraint anchorage of any kind remains optional, and ADR34 only applies if one or more top-tether anchor points or ISOFIX points are installed.

In dual-cab utes, we see two main types of top-tether anchor points: One option is fixed metal bars behind the seat backs, which can be hard to use because once you have clipped the strap to the anchor point and put the seat back in place it is hard to tighten the top tether strap sufficiently. This is especially difficult when installing more than one baby seat, because bringing the seat back forward to connect the second top-tether strap means you need to loosen the first.

An increasingly common top-tether anchor option in dual-cab utes is webbing loops behind the rear headrests. With these, you thread the top tether strap through them and across to a metal anchor or webbing loop behind the headrest of the neighbouring seat. These top tether anchor points have the advantage that they are sometimes easier to access than the metal bars behind seatbacks and it can be simpler to install more than one child seat, but they also have their challenges. In some vehicles, the loops are too small to thread the strap through easily, and the tightening buckle often gets obstructed by the webbing loop. It can prevent you from tightening the top tether strap sufficiently for a proper installation.