When is a carseat too big for the car?

[jhamman]

Good morning!

I noticed recently that almost-4yo DS's shoulders
are getting close to the top slot in his Decathlon.

I've been shopping for a Regent this week,
but I'm now worried that it might be too big for my car
(a 1995 Saturn SW2 wagon).

Is it possible for a carseat to be too big for a car?
If so, what are the guidelines, or rules of thumb?

For example, how much room should be between the carseat
(or the child's knees) and the front seats of the vehicle?
(And is it okay if he just sits cross-legged in the Regent
until we get a bigger car...?)

Thanks so much for your help; I just want to make sure that we're
not making any dumb mistakes as we move up to the next size seat !

[Joolsplus2]

I wouldn't want my kids knees to touch the front seatback...I think that's about my only personal rule...I liked using our Regent in smaller cars, it just seemed so safe!
Do you have a Babies R Us near enough to you that you could go and try the floor model?

If it's too big, you could try something like the Graco Nautilus or if his shoulders are still half an inch from the top slots you should have enough time to wait for the latest and greatest Britax Frontier (harness to 80, booster to 100, side impact head protection wings on a dialing height adjuster).

[jhamman]

Thanks very much for your take on this --
I was afraid there were guidelines for car size versus
carseat size, that I wasn't aware of.

DS (in his Decathlon) still has about 8 or 9 inches
between his knees and the front seatbacks (more room
than I had the last time I flew on Southwest!)

We'll try out the Regent and see how it goes -- thanks again!