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In-depth review

Cybex Sirona S Convertible Car Seat (Manhattan Grey) Review (2027)

In-depth review of the Cybex Sirona S: 360 degree rotation, 50 lb and 49 in rear-facing limits, load leg, and SensorSafe alerts.

TGBy TrueGear Research TeamIndependent editorial teamLast updated How we researchResearch-based assessment · Convertible Car Seats
Specs verified against manufacturer docs
No paid placements
Independently funded by readers
Updated 2026-10-28
Cybex Sirona S Convertible Car Seat (Manhattan Grey) Review (2027) featured graphic
Cybex Sirona S Convertible Car Seat (Manhattan Grey)

Cybex Sirona S Convertible Car Seat (Manhattan Grey)

A 360 degree rotating seat that rear-faces to 50 lb and up to 49 in.

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Our verdict

The Sirona S is the extended rear-facing seat for tall children: a 50 lb weight cap paired with a 49 in height allowance that outlasts every rival here, wrapped in a rotating shell with a load leg and SensorSafe monitoring. The price of that package is width and money; families with room for both get the longest, easiest-loading rear-facing run in the guide.

What we like

  • Rear-facing to 50 lb and up to 49 in, the tallest height allowance in this guide
  • 360 degree rotation on the base with a load leg for stability
  • SensorSafe chest clip alerts for an unbuckled clip, high cabin temperature, and a child left behind
  • Linear Side-Impact Protection with a steel reinforced frame
  • 12-position headrest with a no-rethread harness

What to watch out for

  • About 20 in wide, too broad for three-across or tight small cars
  • The rotating base adds install steps compared with a fixed seat
  • Premium pricing above the Graco and Evenflo extended picks

What owners report: Cybex Sirona S Convertible Car Seat (Manhattan Grey)

Synthesized from recurring themes in long-term owner feedback.

Most praised

  • Rotation makes loading a heavy rear-facing toddler far easier on the back
  • The tall rear-facing height limit keeps long toddlers rear-facing after shorter seats are outgrown
  • SensorSafe alerts give parents a second set of eyes on the chest clip and cabin temperature

Common complaints

  • The width rules out three-across and squeezes small back seats
  • The rotating base install takes longer to get right the first time
  • Premium pricing for a seat many families use in one car only

Who it is for

Parents of tall toddlers who want maximum rear-facing time and rotation, in a car with a wide back seat.

Height is the real limit, and Cybex knows it

Most extended seats pair a 50 lb cap with a 43 to 48 in height allowance, and tall children hit the height line first. The Sirona S allows rear-facing up to 49 in, which can mean extra months of the safest orientation for long-legged toddlers. The 12-position no-rethread headrest keeps the harness placed correctly across that whole run.

Rotation with a load leg

The seat rotates 360 degrees on its base, so a heavy toddler loads from the door side instead of being threaded over the shell. Uniquely among the rotating seats here, the base also carries a load leg and an EasyLock Bar install, and Linear Side-Impact Protection pods sit on the door side of the steel reinforced frame.

Width and cost, stated plainly

At about 20 in wide the Sirona S is one of the broadest convertibles in this guide: three-across is out, and compact cars will feel it. It is also premium priced with no booster mode at the end of its 65 lb forward-facing run. Buy it for the rear-facing years and the rotation, not as a decade seat.

Key specifications

Rear-facing
4 to 50 lb, up to 49 in
Forward-facing
22 to 65 lb
Rotation
360 degrees on base
Safety tech
Load leg, SensorSafe chest clip, Linear Side-Impact Protection
Harness
No-rethread, 12-position headrest
Width
About 20 in

Sources: Amazon listing, CamelCamelCamel, Desertcart product details

Also consider

Evenflo Revolve360 Extend

Evenflo Revolve360 Extend

A rotating all-in-one that spins for easy buckling to booster age.

Why consider it: The other rotating extended seat, with a 48 in rear-facing height allowance and a longer all-in-one lifespan.

  • Rear-facing: 4 to 50 lb, up to 48 in
  • Forward-facing: 22 to 65 lb, up to 49 in
Check priceAdd to cart
Graco Extend2Fit

Graco Extend2Fit

50 lb rear-facing with a legroom panel for tall toddlers.

Why consider it: The 50 lb benchmark with a legroom panel, at a mid price and without rotation.

  • Rear-facing: 4 to 50 lb, up to 49 in (head 1 in below handle)
  • Forward-facing: 22 to 65 lb, up to 49 in
Check priceAdd to cart

Research-based assessment. TrueGear has not hands-on tested this product; this evaluation synthesizes manufacturer specifications, retailer documentation, and published expert reviews.

Questions, answered

How long can a child rear-face in the Sirona S?

From 4 to 50 lb and up to 49 in tall, the tallest rear-facing height allowance in this guide. Most children reach the height limit in the preschool years.

Does the Sirona S fit three-across?

No. At about 20 in wide it is one of the broadest seats here; the three-across guide lists the 17 in class seats that do fit.

What does SensorSafe do?

The chest clip connects to a phone app and alerts for an unbuckled clip, high cabin temperature, a child seated too long, or a child left behind in the car.

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