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Britax Marathon G4.1 Convertible Car Seat Review

What most parents are thinking- Is this the right car seat for my child ?

It’s time to get some car seat answers.

There are a few factors to consider before choosing the right car seat such as, should you get an infant seat or a convertible one? Which one is safer? Which one will be more comfortable?  Britax came up with a better version of it’s Marathon G4 Convertible car seat, the Britax Marathon G4.1 Convertible Car Seat, it’s one of the safest seats in the market and I absolutely recommend it for every child that’s past the newborn stage.

Image of Britax Allegiance 3 Stage Convertible Car Seat - 5 to 65 Pounds - Rear and Forward Facing - 1 Layer Impact Protection , Static

Once you’re in the market for a new car seat, it helps to know what other parents have done.  For some it’s easier to start off with an infant seat and move on to a convertible car seat as their child grows. For others it’s actually more cost effective to get a convertible or an all in one car seat. That may work out great for your wallet and even better for your storage aka garage. 

Basic difference between an infant and a convertible car seat

An infant car seat is always a rear facing seat while a convertible car seat can be both rear and forward facing. Do remember that most states have car seat laws requiring babies to be kept rear facing up to 20 lb with minimum age of 12 months. That means regardless of which car seat you eventually buy, the child should be kept rear facing  for at least the first year. 

See our full coverage of convertible car seats here.

Image of Britax Allegiance 3 Stage Convertible Car Seat - 5 to 65 Pounds - Rear and Forward Facing - 1 Layer Impact Protection , Static

Once they’ve outgrown the rear facing phase as per the law and weight/height requirement they will be moved on to a forward facing car seat. The convertible car seat is the one that can be both rear facing and forward facing. Typically the convertible car seat allows for the child to be rear facing till up to 40 – 65 lbs.

Image of Britax Allegiance 3 Stage Convertible Car Seat - 5 to 65 Pounds - Rear and Forward Facing - 1 Layer Impact Protection , Static

Which one should you choose?

A convertible car seat is definitely more bang for your buck since you won’t be needing to purchase multiple seats. Convertible car seats normally don’t attach to strollers or click and go frames. In other words, you should aim on getting a stroller that works for newborns/infants. Or use an infant carrier for the better part of the baby’s first year.

Installation Videos


When on the go, a safe ride is all you need

I don’t know about you but I like car seats that win awards. In my mind they’ve done something right to win that. The Marathon G4.1 has all that! It’s been endorsed by SafeWise Recommended (2016), BabyGearLab 2016 Editor’s Choice and Baby Center Mom’s Pick 2014.  

Winning all these safety awards were mainly due to the signature Britax SafeCell Impact protection, which has steel bars to reinforce the structure and side impact protection is built in. That roughly translates into a really safe car seat for your child in case of a collision . Even the base, harness and the tethers are all designed to absorb maximum impact

As if the awards were not enough,  what makes the Marathon G4.1 even better is that it has a lot of the features from the Boulevard and Advocate G4.1. Think of it as a more budget friendly option if you were looking to invest in either of the two.

Image of the Britax Marathon G4.1 Convertible Car Seat, Static

They also have something called a staged release stitches. With that implemented, the car will not jerk in one single motion in case of an impact  thus reduce the forward jerks or movements during a crash. When it comes to safety I would definitely appreciate something like this for my child.

Grows with your child

The Britax Marathon G4.1 Convertible Car Seat can be used as both a rear-facing car seat for children with certain age, weight and height requirements. That is, if your little one weighs between 5-40 pounds and is less than 49” tall, he/she should be able to sit in the rear-facing position. Although it would probably be better for infants that are a little bigger than 5 pounds in my opinion.

Once they grow taller they surpass the rear facing weight and height limit as well as the 12 month mark, it is recommended to turn the seat in forward facing position. The weight limit for that is between 20 t0 65 lbs.

The Marathon G4.1 harness and buckle allow for adjustment as your child’s size changes. The harness 10 position adjustments while the buckle has 2 outwards adjustments.  For younger babies the harness fit seems to hit mid thigh causing the harness to dig into the thighs (depending on the child’s size)

I’m surprised at how common this issue, you definitely don’t want your baby to get hurt just by being buckled up in a car seat.I would definitely encourage you to go in-store to check if your child fits well in the seat and to make sure the harness or the strap do not hurt those cute little thighs.

Image of the Britax Marathon G4.1 Convertible Car Seat, Static

Easy to keep those germs off?

The Britax Marathon is pretty easy to clean and the manual has pretty concise instructions on how to do it. For the shell and the harness a simple sponge cleaning with some mild soap and warm water. Towel dry is adviced.  Rinse the buckle thoroughly and again towel dry. The cover comes off and can be hand washed with cold water and then lay flat.

I do question the quality of the cover though as even wiping it causes the liner to fray or fabric stitching come apart. With infants/toddlers you know the cover will be washed a lot and to have it disintegrate after a few washes is a big no no. It would be a great idea to keep a hold of your warranty and receipt with you in case that does happen.

Some Recline

The Marathon, which isn’t as great as some of the other Britax models but hey some recline is better than none I suppose. It’s definitely not enough for younger babies. Do keep this in mind if you’re thinking to making this purchase for your infant.

Many people tend to advice on the use pool noodles or rolled towel/blankets to get more recline. From a safety point of view that’s just plain wrong. If you need to do that to your car seat to get your infant more comfortable, then it’s time to invest in a better seat.

Quick and Easy to install

The latch connectors are pretty easy to lock on to place. One click and you should be good to go.  A lot of the times the instructions manual may not be enough. I normally watch a YouTube video by the manufacturer to make sure I’m installing it correctly. Or just have the local fire station install it the first time. It would be a good idea to try to install it in front of them once to ensure you’re doing it right.

Image of the Britax Marathon G4.1 Convertible Car Seat, Static

On the go, on the fly

FAA approved the Marathon G4.1for airline travel. Which means your plane rides just got a teeny bit easier!  Great news for you if you are planning to purchase a seat for your little one. I suggest getting a window seat so that it doesn’t cut in someone else’s elbow room.  

If you’re thinking that I don’t want to carry the car seat on the plane, trust me you do. It’s for their safety and your sanity. Having them contained in the car seat will be the best decision you’ve ever made. In your entire parental life.


Different Colors

Color options for the Marathon G4.1

Britax Marathon G4.1 Convertible Car Seat, Static

Customer Reviews

Here’s what the general opinion is regarding Britax Marathon G4.1:

4.5 Stars, 288 Reviews – BuyBuyBaby.com

4.5 Stars, 287 Reviews –  Walmart.com

4.6 Stars, 297 Reviews – Kohls.com

4.6 Stars, 307 Reviews – Target.com


  • Great Safety Features
  • Quick and easy installation
  • FAA approved
  • Has a lot of the features of the pricier Britax Boulevard and Britax Advocate


  • Cover seat fabric quality issues
  • Not very infant friendly
  • Not enough recline

Ease of Use Ratings

Although safety should always be a leading concern when it comes to our children, you shouldn’t obsess about the safety differences between car seat brands. They are required to pass strict federal safety tests before being sold in the US market.

However, getting the installation or usage of a car seat wrong can introduce safety issues. That is why the National Highway Traffic Safety Administration (NHTSA) issues ease of use ratings (see below) for each car seat. The easier to use and the clearer the instructions, the more likely your child is to be buckled up properly every time.

The  Marathon G4.1 received an overall rating of 4 stars in forward-facing mode.

NHTSA ease of use rating for the Britax Marathon G4Forward-Facing
Credit: NHTSA

My Recommendation

I’m definitely a mom on the go with a 2 year old, so she is always running around errands with me.  While doing so, her comfort and safety are of huge importance to me. Having said that I would not have purchased the Britax Marathon G4.1 Convertible Car Seat for her as an infant.  She’s on the smaller side so the harness would certainly be digging into her thighs. And not having enough recline for an infant is a deal breaker for me. That’s just asking for trouble and making the whole ride with two grumpy humans instead of just one sleep deprived one (me!).

I will however recommend it for older babies who are at least able to sit up unaided with a supported neck.  If you do decide to purchase a separate car seat for your infant, do remember to budget for the cost. Until then keep those tiny toes safe and enjoy the ride. 🙂


Ayesha Ahmed
Ayesha Ahmed

I'm a stay at home mom to a 2 year old daughter. My background is in consumer behavior so I'm super critical and wide angled when it comes to making baby product purchases. Unless they are so darn cute that all logic escapes my mind:)

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