Convertible Car Seat V. Booster Seat

So your child is rear facing now and will be until age 2? The Britax Frontier requires children to be 2yrs old and at leat 25lbs (I believe) to use.

What seat is he in now? What is his age, height and weight? A rear facing car seat is outgrown when the child reaches the rear facing weight limit or there is less than one inch of shell above the childs head. The harness needs to be at or below teh shoulders for rear facing. When forward facing the seat is outgrown when one of three things happens, the child goes over the weightl imit, the ears are level with the seat back, or the shoulders go over the top harness slot. The harness must be just at or above the shoulders for forward facing.

A harnessing booster is just as safe as a convertible car seat. A harnessing booster usuallly won't have as much side impact protection, but the Frontier DOES. Also most harness booster seats make awful boosters (Alpha Omega, Safety 1st 3-in-1, Eddie Bauer 3-in-1, etc) they fail crash tests consistently. The Frontier, Graco Nautilus both make good booster seats, so the yare good choices if you plan to use them as booster seats some day. Avoid the Alpha omega and others listed above in parenthesis, they aren't worth the money.

What BeckyW said :-). And just FYI since car seat names can be a bit confusing:
A "convertible" seat is a harnessed seat that can be used rear facing or forward facing

A "combination" seat is a forward facing seat that can be used as a harnessed seat or (after the harness is outgrown) as a belt positioning booster.

A "booster" seat is a seat that positions the car's lap and shoulder belt to fit the child - it has no built in harness.

whether it's more appropriate for your son to be in a combination or convertible at age 2 will depend a bit on his size - unless he's way up close to the rear-facing weight limits of a convertible seat (which these days can be 35-40 lbs.), most child passenger safety techs would recommend keeping a 2YO in a rear-facing convertible seat - this link has many references for why: http://carseatblog.com/?p=5168

Do lots of research as they are changing and upgrading ALL the time. And I have found that I am more happy with other brands innovations as opposed to the Britax, which is one of the ‘names.’ but that just imho. I would suggest getting a full convertible and leave your son rearfacing until he doesn’t fit the seat anymore. He will likely grow out of length (head 1" below the top of the carseat) before weight (new ones rear face to 40-45 lbs as opposed to 25-30). Then keep him in a front face 5-pt harness as absolutely long as they fit in the seat with the proper strap adjustment. They are SOOO much safer with a 5-pt harness...don’t rush him out of it, its not one of the “milestones” to celebrate like walking :) Be sure to check your vehicle manufacturing guidelines for how long it is appropriate to keep a seat in the LATCH positions (usually up to 85 lbs I think). When they can’t do LATCH and lose that 5pt harness, keep them in a high-back booster as long as possible. I fully expect my girls to be in their 5-point harnesses at least into kindergarten if not longer. It is just plain safe and makes sense...and there is a big trend and support that way so I don’t think it will be an issue in school. My girls are both small for their ages and I anticipate they will have to be in a high-back booster+belt or backless booster+belt throughout most of elementary school.

for info check out
www.car-seat.org
www.seatcheck.org
www.joelsjourney.org
www.healthychildren.org

Just some input on the Britax Frontier ... we own it and LOVE, LOVE, LOVE it! Soooo glad we stuck w/ the 5 pt harness. Our daughter if 5, weighs 43 pounds and we'll have this seat for a long time. Definitely worth the money and peace of mind. Good luck!

Essentially if you are talking about a seat that converts to a booster it is still a convertible just not able to rear face. I have two of these "covertible" car seats for my nearly 4 year old son and they work great. He is tall for his age and will probably still fit in the 5 point harness until he is nearly 6. Most true convertible (rear and forward facing) are only rated up to 40 lbs so you would have to buy another when he reaches that weight. We have the Evenflo Generation 65 for my oldest son (rated to 80 lbs) and the Learning Curve True Fit (rear, forward and booster) for my youngest and it is rated to 65 lbs. But I do have a suggestion, you didnt say how old your son was but rear facing for as long as you can is the best. We plan in trying to rear face our youngest until he is two.

Britax Frontier will be fine because it IS like a convertible seat as long as you use the 5 point harness. The only difference is that it can never go rear-facing. Then, you have the benefit of converting it to a Booster seat later when he's bigger and older.

We recently bought a Frontier for my son as well, who turned 3 in May. It's a great seat.

EDIT: If you are getting a new seat when your son will be forward-facing, why would you need one that will also work rear-facing? I would think you would want the forward-facing / booster seat at this point. You can use the seat with the 5-point harness as long as your son meets the seats requirements, and therefore would be safer than switching to booster too soon. As I stated before, you probably won't switch to booster until age 5 or so.

Convertible means that it's 2 car seats in one. You MUST have a 5-point harness when switching to forward-facing. Booster seats are for about age 5.

The car seat we have is a forward-facing 5-point harness, but then can be used as a belt-positioning booster.

I don't know which way to go, since I don't know about the Britax Frontier 85. I see that some posts are saying that the Frontier isn't rear facing. Another option of a seat that is rear facing and 85 is the Sunshine Radian 85. I have the 65 as a travel seat, and it is great. It is a convertible seat that goes up to 65 lbs (85 is to 85 lbs), and mine goes up to 51 or 53 in (better than my Britax Marathon, which is only 49 in). The height is more important fr us since my son is tall and thin, I highly doubt he will get to 65 lbs by the time he is 8 (I think this is true for most kids). These are actual convertible seats rather than booster seats. I haven't used it as a rear facing seat (you have to have an additional piece I don't want to fly with), but we do rear face at home with our Marathon, and my son will be 2 at the beginning of September. My goal was to go at least 2 years rear facing, but I plan to go that way as long as my son is comfortable. You don't have to switch to forward facing yet if you don't want. Also, if your son is almost 2 and still rear facing, shouldn't the existing seat go longer rear and forward facing? If it still works, you can keep it and wait, might be something better when your son does outgrow it.