UPPAbaby KNOX Convertible Car Seat Review


UPPAbaby has welcomed a new addition! KNOX joins MESA & ALTA to complete the UPPAbaby car seat lineup and we feel privileged to be the first to review their newest offering! This convertible is the car seat equivalent of a fortress designed to protect your most precious commodity. The UPPAbaby KNOX is modern, sleek and stylish with several unique and innovative safety features.

  • Rear-facing: 14-45 lbs. AND 49” or less AND child’s head is at least 1” below top of headrest
    • Fit Inlay Inserts: 14-25 lbs.
  • Forward-facing: 25-65 lbs., 49” or less AND at least 1 year old (UPPA recommends that children continue to rear-facing until reaching the RF weight or height limit)
  • 8-position, no-rethread harness
  • 2-piece Fit Inlay insert system for children 14-25 lbs.
  • 4 recline positions for rear-facing
  • Dual-zone recline angle indicator
  • SMARTSecure Installation System with tensioning plate, tensioning clips & visual indicators
  • Active Support Headrest with advanced side-impact protection
  • Energy-absorbing base with Koroyd®
  • Advanced energy-absorbing materials utilized throughout the seat
  • Color-coded beltpaths
  • Multi-directional tether strap
  • Side-impact pods
  • Storage pockets for harness buckles
  • Smooth bottom base with won’t damage vehicle upholstery
  • Optional cupholder accessory can be attached to either side of shell
  • 10 year lifespan before expiration
  • Merino wool cover option (JORDAN) is free of chemical flame-retardants
  • Machine-washable cover and inserts
  • FAA-approved for use on an airplane
  • Limited Lifetime Warranty
  • Made in China
  • MSRP $299.99, $349.99 for Merino Wool fashions


Koroyd® collapsible tubular technology

Koroyd®’s welded tubes crumple instantly and consistently on impact, absorbing maximum force in a controlled manner, minimizing energy transferred to the child.

Developed from aerospace safety research and now integrated into the KNOX base, Koroyd compresses and absorbs crash forces, which can further reduce the risk of injury – this is a juvenile industry first.

Multi-Directional Tether

KNOX includes a multi-directional tether that can be used rear- or forward-facing. The use of the multi-directional tether is optional when rear-facing but UPPA strongly recommends its use when possible since it helps to reduce rotation in a frontal crash. When used rear-facing, it is routed around the side of the car seat and attached to the vehicle seat’s tether anchor. The 3rd picture below demonstrates the proper routing of the tether when rear-facing in a pickup truck with indirect tether routing. Forward-facing, use of the tether is always preferred when a tether anchor is available for that seating position. However, if necessary, KNOX can be installed forward-facing with just a seatbelt in vehicles or seating positions that do not have a tether anchor.

KNOX Fashions



JORDAN & GREGORY (Merino Wool)



Harness height minimum: 10″ without Fit Inlay insert (7 ¾” with Fit Inlay)
Harness height maximum: 17″
External widest point: 19” (at SIP pods)
Shell height with headrest fully extended: 26 ½”
Shoulder width: 13 ¾”
Crotch strap depth (single position): 6”
Seat depth: 13 ½”
Seat weight: 32 lbs. with padding, 30.5 lbs. without inlay


Seatbelt is the preferred installation method due to the relatively low latch weight limits. The installation may seem intimidating at first because there is a lot going on under the cover. However, once you understand how to thread the lap belt portion of the lap/shoulder seatbelt under the appropriate tensioning plate and then cinch the shoulder belt portion of the seatbelt thru the appropriate tensioning clip, you will feel a lot less intimidated.

However, this installation will require a significant amount of effort to turn the visual SMARTSecure indicator fully green. You will probably break a sweat. Consider yourself warned

If you are installing KNOX on a vehicle seat that has the ability to recline (even if just a little bit), take advantage of what we refer to as the “reclining seatback trick” to assist you in obtaining a very secure installation. We call this: Work Smarter, Not Harder. 😉

In vehicles such as sedans or pickup trucks when there is no option to use the reclining seatback trick, you may want to enlist the help or a friend or partner. Both Kecia and Heather found the installation to be challenging when the reclining seatback trick wasn’t possible. This challenge was further complicated by the fact that we couldn’t utilize our normal technique of getting behind the rear-facing seat because KNOX sits very high on its base.

Rear-Facing Installation

When rear-facing, any recline position may be used to achieve an appropriate recline. The light blue zone is for kids under 25 lbs. while the darker blue is for kids 25-45 lbs.

In the 14-25 lb. angle range, KNOX is positioned pretty upright. In the 25-45 lbs. angle range, KNOX is positioned bolt upright (similar to how a child would be positioned when forward-facing). The upside of this more upright positioning is that KNOX takes up very little front-to-back space when rear-facing

Forward-Facing Installation

  • Children weighing 25-45 lbs. may use recline positions #1 or #2
  • Kids over 45 lbs. must use the fully upright position.

LATCH Considerations

LATCH Weight Limits:
Rear-facing LATCH weight limit: 30 lbs.
Forward-facing LATCH weight limit: 35 lbs.

Center LATCH installations with Non-Standard Spacing:
UPPAbaby allows the center seating position to be used with LATCH if the lower anchors are spaced less than 22″ apart and the seating position is approved for use with LATCH by the vehicle manufacturer. If the anchors are more than 22″ apart or the manufacturer does not approve that seating position for LATCH, then the vehicle seatbelt must be used for installation.


Each of our 3 models fit very nicely in KNOX. Once the Fit Inlay is removed at 25 lbs., a smaller child may have a significant gap between their body and the single crotch strap/buckle position. This isn’t a safety concern, although it could lead to a bit of slouching as the child settles in the seat.

It’s also important to point out that UPPAbaby doesn’t require the usual “at or below” harness positioning when rear-facing. Their manual states that the Active Support Headrest should be positioned in a way that allows a little bit of space between the bottom of the headwings and the child’s shoulders. They specifically state that the space between the two should be equal to or less than 1 finger width. Of course, that’s pretty subjective depending on whose finger you’re talking about. Their reasoning for this stipulation has to do with head containment in a side impact crash. In this case, having the harness positioned slightly above the child’s shoulder level wouldn’t have any negative consequences in a crash because of KNOX’s more upright positioning when rear-facing.

9 months old, 18 lbs., 29″ (using Fit Inlay with and without back support cushion)

4 yrs old, 34 lbs., 39.5″ (she is over the weight limit for LATCH rear-facing; if she was actually riding in this seat, it would have to be installed using the seat belt)


5.5 yrs old, 43 lbs., 44″


All KNOX covers and inserts are machine-washable—cold water, delicate cycle, and front-loader preferred.

There is an optional cup holder accessory included with KNOX.

UPPAbaby offers a LIMITED LIFETIME WARRANTY on all their car seats and boosters. To receive this extended warranty, customers must register their product within three months of purchase and provide a valid receipt from an authorized retailer. The lifetime of the product is defined by its expiration date. For KNOX, that means a 10-year limited warranty for the original owner! It would be foolish not to take advantage of this so please register your UPPAbaby car seats soon after purchase.


KNOX is FAA-approved for use in an airplane

This car seat has a lifespan of 10 years from the date of manufacture. It must be replaced after any crash.

Installation with inflatable seatbelts is prohibited

  • 8-position, no-rethread harness
  • Tightening and loosening the harness is smooth and easy
  • 4 recline positions for rear-facing
  • Dual-zone recline angle indicator
  • Very compact in the rear-facing position
  • SMARTSecure Installation System
  • Active Support Headrest with advanced side-impact protection
  • Energy-absorbing base with Koroyd®
  • Advanced energy-absorbing materials utilized throughout the seat
  • Color-coded beltpaths
  • Multi-directional tether strap
  • Side-impact pods
  • Storage pockets for harness buckles
  • Smooth bottom base with won’t damage vehicle upholstery
  • 10-year lifespan before expiration
  • Merino wool cover option (JORDAN) is free of chemical flame-retardants
  • Machine-washable cover and inserts
  • Limited Lifetime Warranty

(In all fairness, these aren’t necessarily problems but we list them here to inform potential consumers of specific KNOX issues)

  • At 30+ lbs., KNOX is one of the heaviest car seats
  • Installing KNOX requires a methodical approach. This isn’t a car seat you can pull from the box and install without reading the directions or watching videos.
  • It sits up high on its base (this could be a pro or con, depending on personal preferences)
  • With a 14 lb. starting weight limit, KNOX is not suitable for a newborn.
  • Installation requires significant effort
  • It is possible to achieve a proper installation that still shows some red in the SMARTSecure visual tension indicator window

The UPPAbaby KNOX is a solid, well-made, premium convertible with unique and innovative safety features. The fit and finishes are all high-end and it’s obvious that there was a lot of attention paid to details.

UPPAbaby was the first manufacturer to offer a Merino wool cover that was free of chemical flame retardants and we’re happy to see that this option is also available on the JORDAN KNOX fashion.

The upright positioning of KNOX in the rear-facing orientation makes it an outstanding option for smaller vehicles with limited space in the back seat. It’s also a great choice for tall parents who just need a lot of legroom up front.

We acknowledge that the sheer weight of this car seat causes it to feel cumbersome and the installation may seem intimidating at first. However, the payoff for your time and effort is a properly installed seat with advanced safety features and generous rear-facing height and weight limits.

We will continue to update this review as we gain more experience with KNOX in the field. For now, we’re excited that the UPPAbaby car seat lineup, MESA, KNOX & ALTA, is complete!

For additional information, please visit the UPPAbaby website: https://uppababy.com/knox/

Thank you to UPPAbaby for providing the KNOX samples used in this review. All opinions and comments expressed are those of CarseatBlog.


  1. Becca April 2, 2023
  2. STEPHANIE KAPLAN August 4, 2022
  3. LL June 24, 2021
    • Kecia June 25, 2021

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