The Top 5 Most Common Car Seat Mistakes

Installing or adjusting a carseat can be a bit tricky sometimes, and we know you’re reluctant to read that enormous (but very helpful) instruction manual. So after having a chat with our mates across the pond – the folks at New Zealand’s fabulous Cheeks in Seats – we thought we’d shine a light on the top 5 most common car seat mistakes that you could be making right now. Don’t beat yourself up if you come across a few of these in your car, we’re here to help and there’s always time to fix them!

5. The top tether strap is NOT used, or NOT used with approved vehicle anchorage point

If your restraint is fitted with a Top Tether – it is essential that it is used, and used with an approved vehicle anchorage point. The top tether is the webbing that comes from the top/back of the seat and has a metal hook on the end which is attached to the vehicle anchorage point. This tether is important for proper installation, because without it, there can be serious ramifications in an accident (or even braking hard). It helps stabilise the top of the car seat, and prevents it from rotating over.

If you’re not sure where your anchorage points are, you should check your vehicle owner’s manual, or contact the manufacturer. Also our Facebook Group can be very helpful!

4. The car seat moves more than 2.5cm at the belt path

Lockie LifestyleGetting a tight install of your car seat can be difficult. It’s important that the seat moves no more than 2.5cm side to side at the belt path. You can check this by wiggling the seat at the base closest to the belt path (not the top of the seat – it is normal for this area to move more than 2.5cm). If your seat does move more than 2.5cm or feels loose, you should reinstall the seat more firmly. When threading the seatbelt through the belt path, put your knee and some weight into the seat to ensure its pushed into the vehicle seat before your clip in the seatbelt. You can use a locking device on the seatbelt to ensure this install stays tight. We recommend using the Lockie, SafeGrip, or Gated Buckle.

3. The harness is NOT ‘Pinch Test Tight’

A tight and well fitted harness is essential to ensure your child is safe in their car seat. If a harness is loose, the child’s head and upper body can move too far forward, and they have the potential to be ejected in an impact. To check the harness, start by buckling your child in their car seat. Then, try to ‘pinch’ the harness strap on the child’s shoulder / collar bone. If you can pinch the webbing, then the harness is too loose and will need to be tightened. If your fingers slip on the webbing and you aren’t able to pinch it, then it’s tight and secure.

Incase you’re not familiar with the Pinch Test, check out this helpful video here to make sure you are doing the check correctly. The Pinch Test should be done every time you put your child in their seat. It only takes a few seconds, and it could save your child’s life in an impact!

2. The harness is twisted

Making sure the harness is tight is half the job done. When checking that the harness is tight, it’s also important to check for twists in the straps. The straps are easily twisted when putting children in and out of their seats. By checking the harness every time, you can minimise the amount and type of twists that occur. Still can’t get that last twist out no matter how many times you flip the straps? Check out this video here for our untwisting hack!

1. Correct harness height

Last but not least, and yes – we’re still talking harnesses! It’s important to make sure that the harness is at the correct height for your child.

  • For rearward facing restraints, the harness should be fitted through the slots or positioned as CLOSE TO AND ABOVE the child’s shoulders, NEVER BELOW.
  • For forward facing restraints, the harness should be fitted through the slots CLOSEST to the child’s shoulders. This means they can be above or below the shoulders, whichever is closest. They should be no further than 2.5cm distance from the shoulder in either direction.

Let us know in the comments if you’ve come across any other issues or have any helpful tips for combating misuse in car seats!

Leave a comment


  1. G Mackey says

    I cannot believe I cannot get a set of instructions/diagrams to re-fit a perfectly good infrasecure car seat in a new car, unbelievable!!!!

  2. Sarah says

    My Diono manual says in rearfacing harness must be at or below the shoulder which is the opposite of what you said above. Is this different between brands?

    • says

      Hey Sarah,

      Thanks for contacting us! All child restraints that are certified to the Australian & New Zealand standards state that in Rearward Facing mode, the shoulder straps should sit at or above your child’s shoulders. When in Forward Facing mode, they should sit as close to your child’s shoulders as possible. It’s likely that your Diono restraint is certified to a different standard than the Australian & New Zealand standard, which is why the instruction manual states otherwise to what we have recommended in our blog post. Hope this helps! 🙂

  3. Nikki says

    I had a “qualified” installer put my first car seat in for me. I paid someone professional because I was worried I wouldn’t do it right… 6mths later I went to uninstall the seat to move to a new car only to discover that the guy had clipped the tether strap not to the baby seat ancor point but rather to the luggage tie down point… it was then that I learnt all I could about car seat instillation and now, almost 5yrs later I’m a bit of a pro if I do say so myself!!!

  4. Nelle says

    Another common one is especially with first time parents and grandparents, the 6 months + seats make them believe ANY 6m+ baby can forward face because the seat recommends so. More education is needed there and clearly marked on the boxes!!😡 Makes me angry to see tiny babies turned because their babies turn 6months and often parents need additional seating.

    • says

      Hey Nelle,

      Thanks for contacting us! We definitely understand your concern regarding this. As the Australian National Road Rules state that a child can legally forward face from 6 months of age, we are bound by advertising to state that children can forward face in the appropriate InfaSecure restraints at 6 months old. That being said, we always recommend following your manufactures guidelines and using the restraint in the appropriate manner – this includes leaving your child rearward facing until they reach the ‘turn to Forward Facing’ should height marker regardless of their age. At InfaSecure we do our best to promote best practice safety and extended rearward facing through educational posts, blog posts and by manufacturing multiple restraints that offer Extended Rearward Facing as a major feature, such as the Achieve and Attain Premium, to try and combat children transitioning from rearward facing to forward facing too early. Below are two of our blog posts that further support Extended Rearward Facing:

      Hope this helps! 🙂

    • Teagan says

      I am a first time mum and my bub is nearly 11 months and still rearward and he will be staying that way as long as possible. I also have an infasecure seat and he hasn’t even reached the shoulder heights yet to even turn him to forward facing.

  5. Mish says

    If the car seat has been sitting in the box unused for 7 years then lent it to a friend for her little one to use for a year and then went back into storage again… does this mean that I now can’t it for my baby? As the date of manufacture is 2011-8-28.. is it dangeours even though it’s only been used 12 months and all other tones been in storage? Thanks in advance 🙂

  6. Caitlin says

    People leaving babies swaddled when strapped in car seats, blankets between child and harness, and putting babies car seat in the front passenger seat. ….. All not great

  7. Katrina says

    Our biggest issue is being a dual cab ute it’s Very hard to tighten the tether strap. Worse now we have two as you need to lean the seat forward to get to the anchor point.

  8. Laura says

    Thanks for this post. Can you clarify the movement aspect of number 4? When I was trained to install (earlier this year) we were specifically advised not to attempt to move the restraint as it can loosen the fit and therefore is invalid.

    • Rachel says

      That is true, however parents will always wiggle the restraint and need a easy way to check the install, so we recommend a small wiggle at the base if necessary. This is easier than trying to describe how to visually assess whether the belt is tight enough.

  9. Trish says

    Hi, I’m just wondering how the head bit should sit, the bit that slides up and down I’m unsure at which height to have it. My son is still rearward facing