Are combination car seats (forward facing with harness/ booster with seat belt) as safe as a forward facing convertible car seat?
My tall 3.5 year old son is only 36 lbs but has almost outgrown the shoulder straps of his Britax boulevard. Is a combination car seat the next best step or should we try to find a convertible carseat with higher shoulder straps?
Hi and welcome!
All seats must pass the same testing. There's no difference safety wise between a convertible seat or a combo seat used in harnessed mode. I would NOT invest in another convertible w/taller top slots, b/c most of the recommended combo seats will last MUCH longer than the convertible seats for the same price, sometimes less. (Exception would be if you will need to pass the seat down--a taller convertible--or if you need to do a three across, b/c some convertibles will work much better in a 3 across than some combo seats).
My son outgrew the Blvd harnessed at about 4 years old. He still fits in his Evenflo Secure Kid 300 at age 5, with room to grow. He's got a good inch or more in the top harness slot. I didn't think he'd make it past 5, but he definitely is! He's 43" tall, almost 40 lbs, and wears a size 5/6 shirt. The Graco Nautilus & Argos, Recaro Pro Sport, Harmony Defender 360, Evenflo Maestro all will last about as long as the Evenflo Secure Kid 300 we have. The Britax Frontier (and it's newer versions) will last a bit longer, esp in booster mode, as they make really tall high back boosters (enough to keep most kids in a high back booster till age 10 or more, which is sometimes necessary if the car has no head support/head rests and low back seats).
And fwiw, how long they last in the seat just depends on how fast their growth rate is and where that growth is. My ds outgrew the Blvd probably around the same size as your ds, and I thought his torso would keep growing at that crazy rate, but instead he sprouted legs! LOL So, if another Britax isn't in your budget right now, chances are, you CAN get him to at least age 5 or even 6 in one of the other combo seats available. (-; (Ah...and the Evenflo SureRide's top slots are over 19", so even though it's a convertible, it's almost as tall as the Frontier for only $99--good budget choice, even though you won't use it's rear facing capabilities for him now.)
hths