Can I put a 3 year old in a high back booster aimed at 4 plus?

[Yahboosnubs]

I was hoping to move my DD (1) into my DS's (3) car seat and move him into a booster seat, but he's only just 3. Does anyone know why the specifications are for 4 up - is it height or weight or both? He is tall for his age but not excessively, and is still only 15.7kg. But it seems mad to buy a new car seat for DD and then in less than a year he will move out of his anyway, especially if I have the high backed one, which seems safer. Thoughts?

TIA

I think it is usually on weight, tends to be from 15kg but check for your particular seat. But I would keep him in a 5 point harness for as long as possible, they are safer.

My 5yo is still in a 5 point harness but my 3yr old is using the seatbelt (they both have Britax Evolva 123 or 123+ so they are used as a high back booster once they have grown out of the harness bit) 3yo was persistently unfastening the harness so a seatbelt was safer than not being strapped in at all

We did for DS1 out of necessity (DS2 outgrew the infant carseat at 14 weeks when his body got too long for the straps, so DS1 vacated the Britax which rearfaces and reclines), but it isn't recommended. A tall slim 3yo will not always have the strength for it, and you can't easily fall asleep in a HBB.

If you do do it, make sure that his shoulders are higher than the main bit and that you adjust the head bit properly.

has dd definitely outgrown her baby seat?

i wouldn't be happy with a 3 year old in a high-back booster personally

We're having this dilemma at the moment. My 3 yo is also only 15kg and I thought the boosters were 18kg/ 4yo. I can't see him being 18kg for quite sometime, and certainly not before he's four later this year. We've still got him in a rear facing besafe which is fine still, but his 12 month old and 12kg brother is rapidly out growing his GP 1 seat. I'm probably going to bite the bullet and just spend the extra on another besafe and accept that it's a big expense but preferable to the alternative.

Thanks for your responses. I hadn't thought about the five point harness aspect. DS can undo the harness already but only does it when we've arrived somewhere (at the moment). DD hasn't quite grown out of her seat yet but it won't be long. Maybe I will have to bite the bullet and spend the money. It's not so much that though, but it seems a waste of a car seat really. Hey ho.

A year is quite a while for them to be in a car seat though - think about it the baby ones are only used for about a year and yet we wouldn't dream of skipping that stage.

Couple of thoughts -

How about buying one which converts from a harnessed seat to a booster, so that DD can go into the existing group 1 seat and DS can go into the group 1/2 seat harnessed for now and then you can remove the harness when you feel he is ready.

How far away is DD's head from the top of the seat? A lot of babies will fit into them past a year, depending on height and the size of the seat, and their growth slows down massively after 12 months. DS finally outgrew his at 18 months, and he is quite tall, so that potentially gives you 6 months or so longer by which time DS might be a bit bigger. It's also safer for her to be rearfacing for as long as possible so this would be a plus too.

Ah just seen your last sentence - thought number 3 is if the money is not a problem, spend the money you would have spent on an extra group 1 seat + booster on one of the extended rearfacing seats which also harnesses until 25kg or something. Keep DD rearfacing in the new seat until DS really outgrows his group 1 seat (as she's younger so it's most important for her to be RF). When DS has outgrown the harnessed seat, swap them - put DD into his old FF seat and put him into the RF one (turned FF if you like) until he outgrows that harness at which point he'll be about 7 and able to just sit on a cheap booster.

The concord transformer xt you can get with an additional cushion for younger children

Actually is the concord transformer t pro

Hmm, good thinking, Bertie - thanks. I shall do some research. Good point about keeping DD rearfacing as long as possible.