Question 4 year old twins outgrown Britax Marathons?

I have identical twin boys who are both 42 inches tall and 42 pounds. I had intended to keep them in their Britax Marathons for at least another year minimum... But my husband and I noticed last week that the shoulder straps were coming from below their shoulders and we tried to adjust the strap height to discover that they already were at the highest setting.

I don't know what to buy now! I think they might actually sit properly in booster seats BUT they fall asleep in the car all the time, so I'm not sure if a non-harnessed booster is a good idea.

We tested out a Graco Tranzitions, which has a harness, but they were too big for our car- it's a Maxda3 and I need to be able to fit myself in the back between their seats occasionally because we have to transport my mom with us sometimes. With the Tranzition it didn't seem like I was going to be able to fit. We tried a Clek Oobr this weekend, and it looked like I would just be able to squeeze back there. My sons looked like they fit in the seat well, the belts were in the right place on them, and I thought maybe the recline function would help with the sleeping in the car thing... But they are expensive seats and the boys are young for boosters... so I'm not sure!

I feel like my choices are shopping for a new car or moving them to the Oobr, neither which I'm not too sure about!

Anyone have any other suggestions for me?! Thank you so much!

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TLDR: 4 year old twins, 42 pounds and 42 inches, shoulders over top height of Britax marathon, need to fit 2 seats and a average size woman in the back of a Mazda3.... help! Thanks!
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What about one Tranzitions and one Evenflo Sureride? They generally puzzle well together. You would put one in the center, then have an outboard seat for yourself.

Did you try the Tranzitions side by side, both installed with seat belt? Installing with seat belts will allow you to pull the outboard seat as close to the door as possible, and for pretty much any seat your boys have likely maxed out the weight limit for a latch installation anyways. This should give you more room outboard, and you also should have better head support outboard. Middle headrests aren't usually sufficient for adults, as you (and anyone in a backless booster) need head support to eye level at a minimum.

Make sure you have the top tethers attached as well. I would definitely continue to try different harnessed seats, as 4 year olds should not be in boosters.

Unfortunately I wasn't able to try two of anything- Toys R Us gave us a hard enough time trying to take the display Tranzitions out to the car to try. Fitting them side-by-side is something to think about though! I honestly wasn't even thinking about my own safety squeezed in the middle. Eeek.

My mom is in a nursing home, and I like to be able to drive her to family parties so she isn't stuck there all the time, which is why we need to fit me in the back sometimes! It's tough trying to do the right thing for everyone- both my kids and my mom!

I also had no idea when we bought the Marathons that they could be outgrown so early!

Thanks for all the suggestions!
Posted via Mobile Device

Amazon has a great return policy! You can't get a Graco Tranzitions there, but they do have the Harmony Defender, which is similar in stats (width, max weight, top harness height, puzzle-ability with Evenflo Sureride) and they have the Sureride, too.