Top pick
RVMattress.comSignature Hybrid
- Hybrid
- 13.25 in thick
- Soft / Medium / Firm
Sleep Foundation: Best Mattress Overall Read review
$1,865RV King - 70x80 · list priceSee price
Keystone Avalanche 378BH mattress size
Main bed70 × 80 inRV king
That's an RV king, 6 in narrower than a regular king (76 × 80 in). A regular king won't fit, so get an RV king in exactly 70 × 80 in.
About the RV king size →Keystone 2022 brochure, 2022.
Bunks38 × 74 in
Bunk. Keystone spec sheet, 2026.
Common RV bunk sizes →
Mattresses in 70 × 80 in
We may earn a commission when you buy through some of these links. It doesn't change which mattresses we list.
Best value
RVMattress.comCopperFlex Essential
- All-foam
- 6 in thick
- five comfort options
$799RV King - 70x80 · list priceSee price
Reviewers' favorite
RVMattress.comAurora Luxe Cooling
- Hybrid
- 13.25 in thick
- Soft / Medium / Firm
Sleep Foundation: Best Mattress for Temperature Regulation Read review
$2,465RV King - 70x80 · list priceSee price
Best hybrid
RVMattress.comCopperFlex RV Hybrid
- Hybrid
- 10 in thick
- Medium-Firm
$1,065RV King - 70x80 · list priceSee price
Best all-foam
RVMattress.comPlank Firm
- All-foam
- 10 in thick
- Firm / Extra Firm
Mattress Clarity: Best RV Mattress for Heavy People Read review
$1,532RV King - 70x80 · list priceSee price
Custom size
Mattress InsiderPark Meadow Encased Coil II
- Hybrid
- 8 in thick
- cushion-firm
Sleep Foundation: Best Mattress for Pressure Relief Read review
Made to 70 × 80 inGet a quote
Bunk mattresses in 38 × 74 in
Some bunks have a rounded corner, so trace yours before a custom cut. A thicker bunk mattress takes headroom from the bunk above.
Top pick
RVMattress.comSignature Hybrid
- Hybrid
- 13.25 in thick
- Soft / Medium / Firm
Sleep Foundation: Best Mattress Overall Read review
$959Twin · list priceSee price
Best value
RVMattress.comCopperFlex Essential
- All-foam
- 6 in thick
- five comfort options
$299Twin · list priceSee price
Reviewers' favorite
RVMattress.comAurora Luxe Cooling
- Hybrid
- 13.25 in thick
- Soft / Medium / Firm
Sleep Foundation: Best Mattress for Temperature Regulation Read review
$1,265Twin · list priceSee price
Best hybrid
RVMattress.comCopperFlex RV Hybrid
- Hybrid
- 10 in thick
- Medium-Firm
$565Twin · list priceSee price
The Avalanche bedroom. Measure the platform, not the old mattress, before you buy.
Bed sizes by year
| Year | Main bed | Bunks | Other beds | Source |
|---|---|---|---|---|
| 2021 | 70 × 80 in King | – | – | Keystone 2021 brochure |
| 2022 | 70 × 80 in | – | – | Keystone 2022 brochure |
| 2026 | – | 38 × 74 in | – | Keystone spec sheet |
Years not listed weren't published.
The 378BH floorplan
Keystone's 2026 378BH floorplan.
Is this your 378BH?
Check the year and length against your RV before you order.
| Year | Model | Length | Sleeps |
|---|---|---|---|
| 2020 | Alpine Avalanche Edition 378BH | 40 ft 7 in | 9 |
| 2021 | Alpine Avalanche Edition 378BH | 40 ft 8 in | 9 |
| 2022 | Alpine Avalanche Edition 378BH | 40 ft 8 in | 9 |
| 2023 | Alpine Avalanche Edition 378BH | 40 ft 7 in | 9 |
| 2024 | Alpine Avalanche Edition 378BH | 40 ft 7 in | 9 |
| 2025 | Alpine Avalanche Edition 378BH | 40 ft 7 in | 9 |
| 2026 | Alpine Avalanche Edition 378BH | 40 ft 7 in | 9 |
Other Avalanche mattress sizes
Sources
- Keystone (keystonerv.com): https://www.keystonerv.com/product/alpine-avalanche-edition/luxury-fifth-wheels/floorplans/378BH
Questions
What size mattress is in the Keystone Avalanche 378BH?
The main bed is 70 × 80 in (Keystone 2022 brochure, 2022).
What size are the Keystone Avalanche 378BH bunk mattresses?
38 × 74 in (Keystone spec sheet, 2026).