Britax Marathon ClickTight vs Diono Radian 3QXT
Both are convertible car seats — here are their published manufacturer specs side by side.
| Spec | Britax Marathon ClickTight | Diono Radian 3QXT |
|---|---|---|
| Stage | Convertible | Convertible |
| Narrow (3-across) | – | ✓ |
| Extended rear-facing | – | ✓ |
| FAA-approved | ✓ | ✓ |
| Lightweight / travel | – | – |
How they differ
- the Diono Radian 3QXT is listed narrow (roughly ≤17″) for fitting three across a back seat; the Britax Marathon ClickTight isn't listed narrow
- the Diono Radian 3QXT lists extended rear-facing (a higher rear-facing weight limit, ~40-50 lb); the Britax Marathon ClickTight doesn't
Where to buy
Check the Britax Marathon ClickTight price on Amazon →
Check the Diono Radian 3QXT price on Amazon →
FAQ
What's the difference between the Britax Marathon ClickTight and the Diono Radian 3QXT?
The Britax Marathon ClickTight is FAA-approved for aircraft; the Diono Radian 3QXT is narrow for 3-across, extended rear-facing, FAA-approved for aircraft. Both are convertible car seats.
Which fits three across, the Britax Marathon ClickTight or the Diono Radian 3QXT?
The Diono Radian 3QXT is listed narrow (~≤17″) for 3-across; the Britax Marathon ClickTight isn't. Three-across fit still depends on your exact vehicle — confirm before buying.
Which is right for my car and child, the Britax Marathon ClickTight or the Diono Radian 3QXT?
That depends on your specific vehicle and child — this page compares published manufacturer specs only, not fit or safety. Check the seat manual, your vehicle manual, NHTSA's car-seat finder and ideally a certified CPST before deciding.
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