The Obnoxious Car Seat Stage – Common problems

Toby has a Maxi-cosi tobi car seat, one of the safest belted car seats, and impossible to buckle crunch!

Toby has a Maxi-cosi tobi car seat, one of the safest belted car seats, and impossible to buckle crunch!

Did you know that around 80% of car seats are fitted wrong or not suitable for the car they are in?

Well, one of my biggest parenting niggles is car seats. I just don’t understand why manufacturers (and don’t forget, I worked for one myself for years) are allowed to sell them online or, for that matter, why parents buy them without checking them out first! I think a lot of it comes down to not really understand the issues, after all you have a big car, so the seat fits. But it doesn’t! I wanted to write a post that would explain why that pesky sales assistant has just told you the seat you so desire for your little one is not compatible for your car, and what the problems you could face actually are.

In the case of your very first car seat, you will likely go for an infant carrier, in which case the only issue you are really going to face is that the seat belt may or may not fit around the seat, however the stage after that (known as Group 1) or if you have chosen to go for a fixed rear facing seat that will last until 4 years of age (known as a group 0+) is a lot more complicated.

This is why I endearingly term this section of car seats ‘The obnoxious stage’ of seats.

For a start, your seat can have problems regardless of whether or not it is isofix (the two metal ‘prongs’ that effectively allow you to clip a car seat into the frame of your car) or belted. People often assume Isofix is an automatic fit in a car – ย it isn’t. It is, however, easier and more likely to fit, and is almost always the safest option as in an accident their is up to 30% give in a seat belt in an accident.

The problems you likely to face with Isofix are:

  • Bucket seats, common in most sports cars – easily fixed by buying a performance pad sold by some manufacturers.
  • The need for a top tether – top tethers act as an additional harness to keep the top of an isofix seat attached to the car too, they are needed in a lot more cases than people think, especially if an isofix seat doesn’t have a leg.
  • Under-floor compartments – common in a lot of family cars, but you would then struggle to fit an isofix seat with a leg support.

I would also like to say to you that isofix is ALMOST always safer, because a very basic isofix seat will lack the additional head impact protection that you need for your child’s safety, it is almost like cutting a corner, because its isofix it doesn’t mean it can afford to lose those vital features.

Moving on to seat belted seat there are a few more problems to consider here:

  • Much the same as Isofix seats, you may need a performance pad for bucket seats. Fortunately not many ‘family’ cars have bucket seats, but a lot of sports cars and luxury or executive cars do.
  • Seat belt isn’t long enough – you would be amazed how often this issue crops up. Seat belts are not standard, they vary in length drastically.
  • The big one ‘Buckle crunch’ (see photo below)- this is the most common problem with belted seats for this stage. Now it isn’t especially easy to explain without showing someone in person but here goes. If you look at the buckle part of your seat belt (the part that is attached to the seats not the bit that comes across you) you will see that it will either be fitted low into your seat, or attached to what we call ‘webbing’ (the same material as the belting that comes across your body) which makes it floppy. When the buckle is on this webbing, it is often subject to buckle crunch, where the part that clips into the buckle bends across the plastic of the seats base. In this instance the seat become totally unsafe, and in the case of a collision the buckle is likely to shatter and the seat become detached. Scary stuff, right?!
  • Contact with the sides of the car, or an inability to get to the buckle – if you can’t get to the buckle because the car seat base is too wide, then you won’t be able to get to it in an accident either, and neither will paramedics or any other safety team member. The same goes for touching the door sides, it increases the impact on the seat, creating plastic to break or snap.
Buckle crunch, possibly the most common issue with fitting car seats.

Buckle crunch, possibly the most common issue with fitting car seats.

I hope this clears up what the reasonsย for the seat not fitting actually are. Its quite common to be told ‘not compatible’ but we don’t get told why, so I hope this helps.

For a lot of manufacturers you can test the compatibility of their seats on their website, however it is always best to go to the retailer and ask them to test the seat themselves and if you are buying in store and they don’t offer this service or have no clue what they are doing – Don’t buy there!

Harriet x

P.s – What do you have in your car? Did you get it fitted/tested?



  1. Avatar
    Charlie Deakin
    June 5, 2018 / 6:27 pm


    Is buckle crunch only on group 1 car seats or can it happen on group 2 & 3 too?

    • Harriet June 5, 2018 / 8:06 pm

      It can happen on them all. x

  2. Avatar
    April 5, 2016 / 2:54 pm

    Hi there, does anyone know if the Maxi Cosi Rubi is prone to buckle crunch? Or if it is buckle crunch proof like the Tobi? I can’t find any information about it anywhere. Many thanks!

    • Harriet April 5, 2016 / 8:02 pm

      Alice that looks like the same fitting as a Tobi – it could be a modernisation. I would contact them to be sure but the way it looks from images I would guess not – like I say, call maxi-cosi direct to check ๐Ÿ™‚

      • Avatar
        April 5, 2016 / 11:12 pm

        Thanks for getting back to me! Did you mean to say “I would guess so” rather than “I would guess not”, as you first mentioned that it looks like it has the same fitting as the Tobi. I tried phoning Maxi Cosi today but gave up after being on hold for over 20 minutes. I sent them an email so I’m hoping someone will get back to me eventually. I’ll let you know what they say if they get back to me. Thanks a million!!

        • Avatar
          April 7, 2016 / 1:16 pm

          I finale spoke to someone in Maxi Cosi but as I expected their answer was very vague, saying it has nothing to do with their seats but with the car manufacturer and that buckle crunch hardly ever happens anyway. I’ve ordered the Rubi. Fingers crossed!

  3. Avatar
    Louise Stone
    April 3, 2016 / 10:29 pm

    Hi, great post!
    I’m intrigued by your comment that says the Toby seat is impossible to buckle crunch? Is this the case? This was a fact we were unaware of until today when we went to try and buy a new car seat! We didn’t try the Toby but is it worth trying?

    • Harriet April 3, 2016 / 10:56 pm

      The Maxi-Cosi Tobi can’t buckle crunch because of the way that the buckle is secured, so to the best of my knowledge, it is on e of the only few belted seats on the market that CAN’T buckle crunch. It is a fantastic seat when used correctly. Personally now I would recommend going for a Cybex extended rear facing seat – times have moved on since I wrote this and they are really a far better choice, BUT if you choose not to and you want/need belted, my recommendations lies firmly with the MC Tobi. H x

  4. Avatar
    January 19, 2014 / 11:43 am

    … so consider my problem. We don’t own a car. But we need a car seat in case we end up in someone else’s car, borrow a car, hire a car, etc. Forcing me to get the seat fitted helps no one.

    • Harriet January 19, 2014 / 7:21 pm

      Hi Giselle, thanks for the comment ๐Ÿ™‚ . I feel your frustration, I used to get people in your situation yelling at me in frustration in store because I can’t simplify the issue. No one forces you to get the seat fitted, but it is plain common sense if not every seat fits in every car, you would need to know whether or not the seat you are putting your child in is safe for them or not. Otherwise, why bother with the seat in the first place if its going to be a liability to safety? I appreciate its a huge hassle for people in your situation, and I wish I could say they made a car seat that was 100% universal but they don’t! Maybe something to suggest to all of the manufacturers ๐Ÿ˜‰

      I hope that instead of being frustrating for you this post has helped you to see some of the issues you might face, so if you jump into a car you can check yourself. Also just to let you know depending on what seat you have, some manufacturers have really good websites that have fit finders, that will tell you if your car seat is compatibleโ€ฆ though what you would do if it wasn’t and you had to go in that car I don’t know!

      Thank you again for the comment,
      Harriet x

  5. Avatar January 18, 2014 / 2:47 pm

    Hi! ๐Ÿ™‚

    It’s nice to see a fellow mum who is interested in car seats and child safety in the car. :mrgreen:

    I do however need to challenge you a little here. hehe :mrgreen:

    There is no safety difference between a correctly fitted isofix car seat and a belted one. ๐Ÿ™‚

    Extended rear facing car seats are also NOT hard to install, I would have to say some are far easier then a lot of the forward facing ones. :mrgreen: Anyone installing a car seat should look in the manual, following the manual makes most things easy.

    As for what type of car seat I use, we have :

    -BeSafe izi Plus (belted car seat , rear faces to 25kg and is super easy to install…. )
    -BeSafe izi Combi Isofix (rear faces to 18kg, there is a forward facing option with belts, but that is not an option)
    -Britax Two Way Elite (rear faces to 25kg and is one of the simplest seats to install)

    Why have I chosen these seats?
    Because rear facing is safer. No matter what sort of collision you are in. ๐Ÿ™‚ A rear facing car seat gives 90-95% protection where as a forward facing car seat will only give 50 – 60%, this includes any impact shield car seat as well.

    Rear facing has now also become more affordable and thus is an option to far more people.

    • Harriet January 18, 2014 / 3:04 pm

      Hi! Its always nice to have someone challenge ๐Ÿ˜‰ ! Thanks for your comments, and as you say its lovely to hear other mums points of views on this topic, like I’ve said before every parent will come into contact with seats.

      I think the difference between isofix and belted is that they do become looser over time, which is why I would class them as safer, as would most manufacturers, or so I have always been lead to believe. Plus there is the issue with not being able to take out all the tension, which cause the best of belted seats to be effectively useless.

      I’m not trying to suggest that extended rear facing seats are harder to fit, but they are a much newer ‘main stream’ concept in the UK. The ‘norm’ seems to be infant carrier, followed by forward facing group 1, or group 123 seat. It is still quite uncommon to see new parents with a group 0+1 seat as the main seat instead of an infant carrier, and even more uncommon to see an extended rear facing seat. Thats the reason I have left them off the post for the most part. I want to dedicate a totally different post to extended rear facing so I can fully explain why they are safer (after years of hearing ‘but he’ll be bored’ or ‘but she won’t be comfy with her legs’ I want to make sure my post is really detailed in safety statistics etc) which I couldn’t really do in this post as I wanted it to be more about why that pesky sales assistant might say ‘no that seat doesn’t fit’. Having worked as a car seat fitted myself, I have actually been accused of just trying to wrangle more money out of someone when the seat had crippling buckle crunch! So that was the purpose of this post, to explain the main problem that might occur, in a quick and easy way.

      I totally agree with you that rear facing is better, if I had my time over both of mine would be rear facing now, but alas I don’t! Maybe next time ๐Ÿ˜‰

      Thank you so much for commenting, I hope you will do so again, especially when I do get the extended rear facing post up, its always great to have different opinions and information!

      Harriet x

  6. Avatar
    Katherine Furlong
    January 18, 2014 / 1:27 pm

    Lovely post and hopefully it’ll raise awareness! ๐Ÿ˜€

    Just a few things though, where did you get the 30% from for give in a seat belt? As I’ve always been informed that it is 10%!

    Also, a rear facing seat that stays in the car til 4 (or 6 years old – 18 or 25kg depending on seat, as we both know seats are suitable on weight not age ๐Ÿ™‚ ) can be a group 0+1, group 1 or group 1,2 depending on it’s weight range. Group 0+ is only to 13kg or when the top of baby’s head is level with the top of the seat.

    I’d have liked to have seen something in this about the crash testing placing the bar 55cm away from the child restraint, and that the seat and dummy must not impact that bar to be deemed safe – so many people go forward facing thinking they can push the seat right back to get more leg room in the front and not leaving a 55cm gap and putting the child at risk of hitting the front seat ๐Ÿ™

    I’ve used a ton of different seats: Britax Baby Safe sleeper, Britax Baby Safe, Maxi Cosi Cabrio (both 0+ seats with the ISOfix base) Britax First Class, Britax Eclipse, Maxi Cosi Rubi, Britax Multi Tech, BeSafe Combi ISOfix, Britax Evolva, Britax Hi-Liner and Cybex Solution X (yeah.. I like Britax!)

    My favourite by far was the BeSafe Combi ISOfix (goes front facing with seat belt, rear facing with ISOfix, used rear facing)

    What made you go for the Tobi?

    • Harriet January 18, 2014 / 2:41 pm

      Hi Katherine,

      I’m pleased you like the post and thank you for the really kind comments, I hope that it helps people understand how vitally important it is to get their car seats checked properly.

      I got the 30% from my last training, I agree 10% when full tension is obtained but because statistically most car seats, even when fitted properly, are not fitted to the maximum tension, there is then up to 30% give. This is what I was given to believe, and it kind of makes sense if you think of it in those terms. Can’t tell you how many times I have seen a seat, take for example the Britax Evolva 123, fitted really well, but just not to complete tension! Its difficult to do, especially on seats like that that are often a grandparents or second carers car seat. Also if people don’t tighten their seats at least once weekly and the slack from the belt loosens of, that can add to the increase in give.

      I wanted this post to focus on the common issues you may find with fitting a car seat, so people could understand that when they go into stores they weren’t just being told they should buy a different car seat to the one they wanted because the sales assistant was trying to sell them up, hence the reason I didn’t mention any safety aspects such as the one you have highlighted (which is super useful by the way, thank you) or not fitting seats in the front of the car. I also steered cleared of extended rear facing seats as I would like to write a post dedicated to explaining them and their benefits. I have a big thing about car safety, so I intend to cover quite a few different topics on them, after all, its something every parent comes up against at one point or another isn’t it?! I did try to pop all of it under the general heading of group 1, I didn’t want it to be too complicated and end up trawling through explanations of the different categories, as I thought I would dedicate that to a separate post again!

      I really love the Tobi, for a few reasons really. Mainly I chose it because I was going to be moving it from car to car, not just mine and my husbands but also other relatives, and although I would have loved Isofix, not every car was compatible. As you will know the Tobi doesn’t suffer from buckle crunch issues, has the brilliant addition head support (which you can see from the post I am big on. I know so many people assume a seat is safer if it is one thing or another, but that impact protection really is so important around the head). I have a bit of a thing for Maxi-cosi, if I had my time over though it would quite possibly be the family fix selection with the Pearl 2 to extend rear facing or even the britax tri-fix, which I just LOVE!

      Thank you so much for commenting Katherine, and for the additional information, I’m sure people will find it really interesting and I hope you will check out and comment on any/all future car seat posts (and anything else that you find interesting!)

      Harriet x

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