In Depth Baby Product Reviews Led by a Pediatrician

Cybex Sirona S Review

Our favorite rotating seat with one-time installation and better padding, but it feels gadgety, weighs more, and is expensive
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cybex sirona s convertible car seat review
Credit: Abriah Wofford
Price:  $550 List
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Manufacturer:   Cybex
By Juliet Spurrier, MD & Wendy Schmitz  ⋅  Jan 5, 2024
79
OVERALL
SCORE


RANKED
#3 of 20
  • Crash Test - 35% 7.2
  • Ease of Installation - LATCH - 20% 8.6
  • Ease of Installation - Belt - 15% 7.6
  • Ease of Use - 15% 9.0
  • Comfort/Quality - 10% 9.0
  • Weight/ Size - 5% 6.1

The Skinny

The Cybex Sirona S is a top-ranked convertible car seat with rotation abilities. This seat can't be beaten for ease of daily functionality like harness adjustment and chest clip use. It also offers superior comfort, more padding than most seats, higher-quality materials like soft fabrics, and impressive construction. This seat is a variety of up-and-coming rotating-style seats gaining popularity for their help putting toddlers inside. Its impressive installation and other metric scores made this option stand out in the category, and we loved almost everything about it. The major downfalls are the slightly below-average crash test analysis results and the higher price. If you have a tighter budget, it will likely be a deal breaker, and if top-crash test scores are your primary goal, it also isn't the right option, and you'll need to compromise your goals or adjust your budget.
REASONS TO BUY
360 rotation
Only one install for RF & FF
Good padding
REASONS TO AVOID
Install is overwhelming at first
Heavy
Expensive
Editor's Note: We purchased and crash-tested 20 new convertible safety seats for a new update to our car seat review on January 5, 2024.

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cybex sirona s convertible car seat review
This Product
Cybex Sirona S
Awards Top Pick Award Editors' Choice Award Editors' Choice Award Best Value Award Best Value Award 
Price $550 List
$399.99 at Amazon
$330 List
$329.99 at Amazon
$250 List
$224.99 at Amazon
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$80 List
$79.99 at Amazon
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Bottom Line A rotating seat with better test results, but the higher price and overall bulk could be a deal-breakerEasy to install and use and one of the best crash test analysis scores make this seat a winner for most familiesBetter crash test analysis and a lower price make this easy-to-install seat an award contender that just missed the markWallet-loving price on a seat that is easy to install and earned better crash test results than mostDespite a lack of padding and a harder LATCH install, this inexpensive option earned impressive crash test results, making it a winner for budget-limited families
Rating Categories Cybex Sirona S Graco 4Ever DLX Graco Extend2Fit 3... Graco SlimFit 3-in-1 Evenflo Tribute 5
Crash Test (35%)
7.2
8.8
8.6
8.5
8.6
Ease of Installation - LATCH (20%)
8.6
7.9
7.8
7.9
4.3
Ease of Installation - Belt (15%)
7.6
7.1
6.4
6.5
5.6
Ease of Use (15%)
9.0
8.0
7.0
7.5
5.0
Comfort/Quality (10%)
9.0
6.5
8.5
8.0
3.0
Weight/ Size (5%)
6.1
7.5
7.5
7.1
7.8
Specs Cybex Sirona S Graco 4Ever DLX Graco Extend2Fit 3... Graco SlimFit 3-in-1 Evenflo Tribute 5
Min/Max Rear Facing Passenger Weight 4-50 lb 4-40 lb 4-50 lb 5-40 lb 5-40 lb
Min/Max Forward Facing Passenger Weight 22-65 lb 22-65 lb 22-65 lb 22-65 lb 22-40 lb
Rear Facing Maximum Height 49 in Top of head must be at least 1 in below handle Top of head must be at least 1 in below handle Top of head must be at least 1 in below handle 37 in
Forward Facing Maximum Height 49 in 49 in 49 in 49 in 40 in
Weight 31.2 lb 21.8 lb 20.5 lb 18.5 lb 9.4 lb
Minimum Rear Facing Length 30 in 25 in 26 in 28 in 29 in
Minimum Seat Width 19 in 19 in 19 in 19 in 18 in
Number Of Recline positions 6 6 6 4 1
Shoulder Harness Positions 12 10 10 10 4
Crotch Strap Positions 3 2 2 3 2
Anti-rebound Device No No Yes No No
Head Support Yes Yes Yes Yes Yes
Infant Positioning Insert Yes Yes Yes Yes No
Harness Type No-rethread No-rethread No-rethread No-rethread Rethread
Onboard Manual Storage Yes Yes Yes Yes Yes
Rear Facing Level Indicator On Seat Bead in water, both sides Bubble, one side Bubble, one side Bead, one side Line on decal, both sides
Booster Mode Available No Yes Yes Yes No
Foam Type EPP Not mentioned Not mentioned EPS EPS
Seat Lifespan 10 years 10 years 10 years 10 years 6 years
Aircraft Certified No Yes in harness mode, No in booster mode Yes in harness mode, No in booster mode Yes in harness mode, No in booster mode Yes
Warranty 2 year limited 1 year limited 1 year limited 1 year limited 90 day limited

Our Analysis and Test Results

Goodbaby International Holdings Ltd. is a German company that owns Cybex. Cybex focuses on functionality and safety in their baby gear. They make various strollers, and some of the options in our best car seats review.

Performance Comparison



The Sirona performed better than the average seat in our crash tests, but there were better-performing options if your goal is the best crash test results.
Credit: GearLab & MGA Research

Crash Test


The Sirona earned a below-average crash test analysis result that tries hard to be average and struggles compared to the higher-ranking competition. While it meets federal guidelines and is considered safe by these standards, it couldn't match the higher-scoring options in our test group.


This Cybex isn't the best Cybex in the group, nor is it as good as several of the competing options we tested.

This chart shows a comparison of the Siorona and Graco 4Ever sensor...
This chart shows a comparison of the Siorona and Graco 4Ever sensor results from our crash testing. Graco 4Ever is one of the best performers, according to sensor data.
This chart compares the head sensor data from our crash tests with...
This chart compares the head sensor data from our crash tests with the Sirona in black and the Graco4Ever in green. The 4Ever was one of the best in the convertible group.

The head sensor results were lower than most and fairly impressive since a lower result is preferable. However, the chest clip score wasn't great and significantly over the average result in the group (lower is better), and it struggled to compete with the competition.

cybex sirona s convertible car seat review - the shell on the sirona has a pop feature design to aid in side...
The shell on the Sirona has a pop feature design to aid in side impact protection.
Credit: Abriah Wofford

The Sirona has a side impact feature that pops out or can be pressed back in depending on if the seat next to it is occupied. We recommend reading the manual for use and to remember it is hard to say what level of protection this offers in a real-world situation.

cybex sirona s convertible car seat review - installing the sirona via latch is not a problem and is fairly easy...
Installing the Sirona via LATCH is not a problem and is fairly easy with an open and visible pathway.
Credit: Abriah Wofford

Ease of Install - LATCH


Installing the Sirona using LATCH is straightforward and one of the easiest in the group, and we preferred it over much of the competition. The main plus here is that once installed, you don't need to turn it around and reinstall it when it is time for forward-facing. It is a one-and-done as long as you aren't switching cars.


The Sirona has push-style LATCH connectors with a red pull-release...
The Sirona has push-style LATCH connectors with a red pull-release strap.
Disconnecting the Sirona LATCH connectors requires a little strength...
Disconnecting the Sirona LATCH connectors requires a little strength to pull the loop, but it is easier for some than the button we typically see.

This Cybex has flexible push-style LATCH connectors with a bead-in-liquid indicator on both sides and a lock-off. The recline adjustment is in the front between the chair portion and the base that curves up, so you don't need to shove your hand between the base and the vehicle seat.

cybex sirona s convertible car seat review - the sirona level indicator is a ball in a channel, and while it...
The Sirona level indicator is a ball in a channel, and while it works well, it would have been easier to read if the lines were darker or thicker.
Credit: Abriah Wofford

The button is easy to press, and it moves smoothly. You have to recline the seat fully to access the belt path cover, and the connectors are in a cubby that is easy to grab by the red release webbing tabs. The pathway has a pop-up lever, and the area feels crowded and could be challenging for larger hands to operate well. The lock-off diagram is not in the same orientation as you will be during installation, which is a minor but important design choice we think should have been caught during development. There is a slight wobble when you tug hard on the side, but it's pretty stable and more stable than the belt installation. The lock-off is convoluted, but it works well.

cybex sirona s convertible car seat review - the load leg on the sirona was a little harder to install than we...
The load leg on the Sirona was a little harder to install than we thought, but not challenging in the end.
Credit: Abriah Wofford

Forward-facing installation on this Cybex requires rotating the seat around and using the tether strap that goes over the vehicle seat back.

The Sirona belt pathway and lock-off are not hard to use, but the lock-off has a learning curve and might not be intuitive for everyone.
Credit: Abriah Wofford

Ease of Install - Belt


Installing the Sirona with the vehicle belt is somewhat more challenging, but it is still easy, and the seat scored higher than the average seat in the group.


cybex sirona s convertible car seat review - there is only one belt pathway on the sirona, as it has the same...
There is only one belt pathway on the Sirona, as it has the same base installation for rear and forward-casing configurations.
Credit: Abriah Wofford

The rear-facing setup includes a bubble level indicator on both sides and a color-coded pathway with a belt lock-off. The setup for installation is not very intuitive, and the space you need to access is very cramped. You need to push the seat and rotate it back to gain access under a front panel and pull a tab to lift the tensioner. The space for the tensioner to open is tight, and it requires constant adjustment with a finicky mechanism that makes the process feel more involved than it really is.

cybex sirona s convertible car seat review - installing the sirona with the vehicle belt isn't as easy as the...
INstalling the Sirona with the vehicle belt isn't as easy as the LATCH connectors, but it still isn't as hard as some of the competition.
Credit: Abriah Wofford

There is a learning curve, and it does get easier. The pathway is shallow, and it requires pushing the lap and shoulder belt in place. You need to ensure they lay flat for them to fit in the tensioner. We like that the belt pull direction is intuitive, but it didn't feel as stable as we pulled. It passed the wiggle test, but it wasn't the best, in our opinion. Overall, it didn't feel like an efficient or intuitive process.

The Sirona lock-off has a two-step lock-off that requires some...
The Sirona lock-off has a two-step lock-off that requires some thoughtful patience to complete if you aren't familiar with these kinds of lock-offs.
The lock-off on the Sirona is a two-step process, and you need to...
The lock-off on the Sirona is a two-step process, and you need to ensure you thread the belt parts flat.

To uninstall the process is just the opposite of installation. The lock-off button is a persnickety button to release, and it is easier if you unbuckle the belt first to relieve some tension on the lock-off.

cybex sirona s convertible car seat review - the chair portion of the sirona swings aside so you can access the...
The chair portion of the Sirona swings aside so you can access the belt pathway location without hindrance.
Credit: Abriah Wofford

Installing in the forward-facing position is the same method as rear-facing; if you don't need to switch cars, you are good to go with rotating the seat forward and attaching the tether.

The Sirona rotates around and reclines using the same internal release mechanism.
Credit: Abriah Wofford

Ease of Use


The Sirona is super easy to use, with a score for day-to-day performance that exceeds most of the competition.


The harness height adjustment on the Sirona can be easily adjusted with a little one in the seat as soon as you notice the need.
Credit: Abriah Wofford

Harness


The buckle is larger and easier to use than the average option. The prongs push in easily, but getting the release takes a little more pressure. The harness prongs have magnet retainers high on each side. They seem almost too high, and the prongs are so small that they don't swiftly attach but require some effort to get them exactly right. But if you use them, you won't need to search for prongs under tiny tushies.

The smart technology in the chest clip of the Sirona connects to an app on your smartphone and can send vital alerts that could save a life.
Credit: Abriah Wofford

The chest clip on the Sirona is unique in our lineup of options. It includes what Cybex calls "Sensor Safe Technology." This chest clip connects to an app on your phone that sends you four kinds of alerts. You need to download an app and set up the chest clip before use. It will even alert pre-listed family members if the nearby caregiver doesn't respond to a "child in car" alert within three minutes.

cybex sirona s convertible car seat review - the sirona has a unique chest clip with smart technology that sends...
The Sirona has a unique chest clip with smart technology that sends various types of alerts to your smartphone.
Credit: Abriah Wofford

It provides the following alerts:

  • Interior vehicle temperature is too hot or too cold (above
35°C / 95°F or below 7°C / 45°F)
  • The chest clip has become unbuckled
  • The chest clip has been buckled for more than 2 hours
  • The device with the app has moved away from a buckled chest clip (i.e., the child has been left in the car)

cybex sirona s convertible car seat review - the buttons on the sirona buckle and chest clip are on the smaller...
The buttons on the Sirona buckle and chest clip are on the smaller side and somewhat harder to press.
Credit: Abriah Wofford

Certainly, the most critical alert is the final one to avoid death from a baby being left in a hot car. The clip is easy to use, and we love the idea of additional safety to help prevent children from being left in hot cars. We worry some parents will turn off notifications after repeatedly being notified when their child leaves the car or about car temperatures, which can happen every 5 minutes or until the temperature is safe.

cybex sirona s convertible car seat review - the sirona prongs slide into the buckle with only a little pressure.
The Sirona prongs slide into the buckle with only a little pressure.
Credit: Abriah Wofford

Tightening and loosening the harness on the Sirona is easier than the average seat in our tests. We didn't feel any resistance on the tightening strap, but there was the need for a slightly more exaggerated pull at the end to ensure a snug fit. The harness release works well, and pulling the harness loose is also smooth. The button is easy to press, but it is deeper into the slot than we thought it would be. You can still use your thumb to operate it if you wish.

cybex sirona s convertible car seat review - the harness height adjustment on the sirona is easy to operate.
The harness height adjustment on the Sirona is easy to operate.
Credit: Abriah Wofford

The shoulder height adjustment on the Sirona is a non-rethread style with 12 height options and three crotch placement options. The buckle strap is easy to move from the top of the seat, and the harness height assembly moves smoothly, especially when pulling it up.

cybex sirona s convertible car seat review - the sirona manual tucks away in a pocket on the back of the seat for...
The Sirona manual tucks away in a pocket on the back of the seat for easy access.
Credit: Abriah Wofford

LATCH Storage


The LATCH connectors are on the side and easy to access. The pull tab on the connectors makes removing them easier, but there is nowhere for the extra strap webbing to go.

Cover


The cover is easy and quick to remove on the Sirona. It has small slots to thread the fabric into and requires pushing it in around the edges; it isn't hard; you follow the outside edge with your fingers.

The Sirona fit even some of the wider sippy cups, but you might want to check yours before setting out on adventures.
Credit: Abriah Wofford

Comfort/Quality


If comfort and quality are your main goals, the Sirona earned a reasonably high score in this metric, with better performance than most of the competition.


The fabric here is a bit rougher than the average. We wouldn't worry about it, but we weren't thrilled either. It has a distinct chemical smell that is a real turn-off, and we imagine this will be worse when left in a hot car. Users might want to air this out for as long as possible before using it.

The Sirona impact foam is EPP, the non-off-gassing type.
The Sirona impact foam is EPP, the non-off-gassing type.
The Sirona has a side clip cup holder that looked pretty scuffed...
The Sirona has a side clip cup holder that looked pretty scuffed after minimal testing, but the cover tucks in nicely for a finished look.

The infant insert has great head padding, and the whole insert creates a good space for small infants. It has a lumpy look, and there is an inch gap in the back panel between the bottom and back portions. It seems more significant, given the thicker padding, and we wonder how this will work with a baby.

cybex sirona s convertible car seat review - the sirona is one of the more comfortable car seats in the group...
The Sirona is one of the more comfortable car seats in the group, with little ones cushioned for cozy napping.
Credit: Abriah Wofford

The main seat padding is almost like an overstuffed armchair from the 80s (look it up if you need to, youngins). No part looks or feels neglected here, and we like that the padding is in all locations equally. The padding has some substance and doesn't squash like it is full of air; instead, it feels like some dense memory foam with a slow bounce back after pressure is applied.

cybex sirona s convertible car seat review - if the sirona base gets gunk or liquids dried inside, it could make...
If the Sirona base gets gunk or liquids dried inside, it could make it more challenging to rotate.
Credit: Abriah Wofford

The shell back is flush, but the rotating bottom can be a place for gunk to hide, and it isn't hard to imagine that the gunk will cause rotation issues over time, something confirmed by online reviewers. There is one cup holder that can go on either side. It attaches to the outside for quick clean up, but it isn't as nice looking as those that fit in the chair itself.

cybex sirona s convertible car seat review - the sirona is heavier for the group, but it is relatively narrow for...
The Sirona is heavier for the group, but it is relatively narrow for a seat that rotates.
Credit: Abriah Wofford

Weight/Size


The Sirona is light for a rotating seat but isn't carry-worthy at 31.2 lb. We suspect no one will want to carry this big guy with his 7 lbs weight difference over the average and his longer length from front to back. With a length of 29.8 inches, it might not be a good choice for small cars or tall parents as the front vehicle seat might be unable to move back far enough to accommodate the passenger and the car seat.


The Sirona is relatively narrow, given how long and heavy it is, with a width of 18.5in. This is just hair below the average for the group of 18.6 in. The narrowest option is 16.9, but neither of those competitors scored well in key metrics.

cybex sirona s convertible car seat review - if a rotating seat is what you crave, and your budget allows it...
If a rotating seat is what you crave, and your budget allows it, then the Sirona is our favorite rotating option.
Credit: Abriah Wofford

Should You Buy the Cybex Sirona S?


If you're looking for a rotating seat, the Sirona is our favorite. With a 360-spinning design you only install once for forward-facing and rear-facing, this seat is tough to beat. It combines the higher quality and comfort Cybex is known for and comes with easy-to-use features parents love. If you desire a rotating seat, it is hard to beat this Cybex option. However, the Sirona is expensive and huge, either of which could be a deal breaker for some families. It also didn't earn crash test results above the average, so while safe, it isn't a standout. If you aren't set on a rotating seat, and there are reasons not to be, we don't think the Sirona is suitable for everyone, and it is only if it meets your goals of rotation that it should be your go-to option.

What Other Convertible Car Seat Should You Consider?


The Graco 4Ever DLX is a non-rotating seat that scored somewhat better than the SIrona and will save you money to boot. This Graco has one of the best crash test analysis scores and comes with dual cup holders. This seat is easy enough to install and has straightforward features. If you want rotation, but you are okay if it only works rear-facing, then the Baby Jogger City Turn is one to consider. This seat has better crash test analysis than the Cybex and is easy to install and use. It has a similar price point and would have won an award for rotation if it worked forward-facing, too.

Manufacturer Video



Juliet Spurrier, MD & Wendy Schmitz