Great all around
RVMattress.comSignature Hybrid
- Hybrid
- 13.25 in thick
- Soft / Medium / Firm
Sleep Foundation: Best Mattress Overall Read review
$1,465Queen · list priceSee price
Grand Design Solitude 378MBS mattress size
Main bed60 × 80 inQueen
That's the same size as a regular queen, so any standard queen mattress fits.
About the RV queen size →Grand Design spec sheet, 2025.
Bunks30 × 72 in
Bunk. Grand Design spec sheet, 2025.
Common RV bunk sizes →
Mattresses in 60 × 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
$524Queen · list priceSee price
Firm
RVMattress.comPlank Firm Luxe
- Hybrid
- 13 in thick
- Firm / Extra Firm
$1,598Queen · list priceSee price
Cooling
RVMattress.comAurora Luxe Cooling
- Hybrid
- 13.25 in thick
- Soft / Medium / Firm
Sleep Foundation: Best Mattress for Temperature Regulation Read review
$1,999Queen · list priceSee price
Heavy duty
RVMattress.comTitan Plus Luxe
- Hybrid
- 13 in thick
- Plush
$1,665Queen · list priceSee price
Helix pick
HelixHelix Midnight
- Hybrid
- 11.5 in thick
- Medium Feel
Sleep Foundation: Best Mattress for Side Sleepers Read review
$1,183Queen · list priceSee price
RV hybrid
RVMattress.comCopperFlex RV Hybrid
- Hybrid
- 10 in thick
- Medium-Firm
$799Queen · list priceSee price
Custom size
Mattress InsiderLuxury Gel Memory Foam
- Memory foam
- 8 in thick
- not stated
Made to 60 × 80 inGet a quote
Bunk mattresses in 30 × 72 in
Some bunks have a rounded corner, so trace yours before a custom cut. A thicker bunk mattress takes headroom from the bunk above.
Custom size
Mattress InsiderLuxury Gel Memory Foam
- Memory foam
- 8 in thick
- not stated
Made to 30 × 72 inGet a quote
The Solitude bedroom. Measure the platform, not the old mattress, before you buy.
Bed sizes by year
| Year | Main bed | Bunks | Other beds | Source |
|---|---|---|---|---|
| 2021 | 60 × 80 in Queen | – | – | Grand Design spec sheet |
| 2022 | 60 × 80 in Queen | – | – | Dealer report |
| 2022 | 60 × 80 in Queen | – | – | Grand Design spec sheet |
| 2025 | 60 × 80 in Queen (king optional) | 30 × 72 in | – | Grand Design spec sheet |
Years not listed weren't published.
Is this your 378MBS?
Check the year and length against your RV before you order.
| Year | Model | Length | Sleeps |
|---|---|---|---|
| 2021 | Solitude 378MBS | 40' 2" | – |
| 2022 | Solitude 378MBS | 40' 2" | – |
| 2025 | Solitude 378MBS | 40' 2" | 7 |
Other Solitude mattress sizes
Sources
- Grand Design (granddesignrv.com), archived copy: https://web.archive.org/web/20201117213406/https://www.granddesignrv.com/showroom/2021/fifth-wheel/solitude/floorplans/378mbs-378mbs-r
- Grand Design (pdf.granddesignrv.com): https://pdf.granddesignrv.com/SpecSheet/Solitude/Solitude-SpecSheet-378MBS.pdf
- Grand Design (granddesignrv.com), archived copy: https://web.archive.org/web/20211028140606/https://www.granddesignrv.com/showroom/2022/fifth-wheel/solitude/floorplans/378mbs-378mbs-r
- Grand Design (granddesignrv.com), archived copy: https://web.archive.org/web/20250213162024/https://www.granddesignrv.com/fifth-wheels/solitude/378mbs
Questions
What size mattress is in the Grand Design Solitude 378MBS?
The main bed is 60 × 80 in (Grand Design spec sheet, 2025).
What size are the Grand Design Solitude 378MBS bunk mattresses?
30 × 72 in (Grand Design spec sheet, 2025).