Here is how these two sleeping bags compare on the numbers. The Grenadier 5 takes a modest overall edge, led by low weight, but the Flex 5 has its own case.
| Katabatic Gear Grenadier 5 | Katabatic Gear Flex 5 | |
|---|---|---|
| GearScore | 85✓ | 83 |
| Comfort rating | 15 °F | 15 °F |
| Weight | 29.5 oz✓ | 29.9 oz |
| Warmth-to-weight | 6.6 /100g✓ | 6.5 /100g |
| Packed size | 9.5 L✓ | 12.5 L |
| Fill power | 850 FP | 850 FP |
| Price | $439✓ | $449 |
| Fill | Down | Down |
| Style | Quilt | Quilt |
| Shape | Quilt | Quilt |
Highlighted cells mark the better spec: Grenadier 5 in blue, Flex 5 in amber. A blank spec is never counted as a win. A lower comfort rating in °F means a warmer bag, so the warmer bag takes that row. GearScore is the overall rating (0 to 100); re-weight it on the full bag comparison. Prices are current MSRP.
The Katabatic Gear Grenadier 5 against the Katabatic Gear Flex 5 is a study in priorities. The Grenadier 5 wins on low weight and warmth-to-weight, and the Flex 5 pushes back on value.
The Grenadier 5 is 1 oz lighter, stronger on warmth-to-weight, and more packable (9.5 L vs 12.5 L). Their GearScores land within a couple of points (85 vs 83), so neither runs away with it.
Pick the Grenadier 5 if you care most about low weight and warmth-to-weight, which makes it the better call for counting grams on long miles. Pick the Flex 5 if you would rather save the difference.
The Katabatic Gear Grenadier 5. It is 1 oz lighter than the Flex 5.
The Katabatic Gear Grenadier 5. It is stronger on warmth-to-weight than the Flex 5.
They are nearly tied at 85 and 83 on the default algorithm, so re-weight the score to your own priorities to break the tie.
It depends on your priorities. Go with the Grenadier 5 for low weight, or the Flex 5 for the price. The spec table above shows exactly where each wins.