2021 Grand Design Momentum body & structure problems

Related recalls

No recalls on file.

What owners say

1. Filed Jul 14, 2026TXBody & Structure

   We own a 2021 Grand Design Momentum 393g toy hauler that has severe frame flex and bolts in slide have started backing out. We noticed this when driving and the extreme pushing/chucking when accelerating or braking and also the visible failure on the unit. We have contacted Gran Design, the manufacturer, for warranty repair and was able to go see the unit when they torn down to look at frame. The side walls were both broken and wall frame fell out when opened up. The unit is…

   NHTSA complaint #11750219 · source
2. Filed Jul 8, 2026COBody & StructureOther / Unknown

   I am reporting a serious, progressive structural defect involving excessive frame flex and structural failure on a 2021 Grand Design Momentum 395MS fifth-wheel RV. This complaint directly aligns with the ongoing NHTSA investigation PE24-0209. The unit exhibits clear and worsening structural integrity failure, including: Slideouts and doors open during transport. Upper deck walls moving under load Lag bolts missing or backing out and pushing through flooring At least one…

   NHTSA complaint #11749089 · source
3. Filed May 24, 2026MTBody & Structure

   Regarding 2021 Grand Design Momentum 376THS: Compartment doors popping open during transport; Grand Design Customer Satisfaction Campaign TSB-24-001 dated 11/1/2025 regarding frame flex and wall securement. Returned to dealer on 12/1/2025 for inspection. Dealer found the following: All doors except p/s compartment door warped or bowed; P/S cracking in sidewall paneling on slides Front cap mollding broken screws Deformation or cracks at expansion joint located under upper…

   NHTSA complaint #11739799 · source
4. Filed May 22, 2026FLBody & StructureOther / Unknown

   Scheduled appointment with dealer for the Grand Design Frame Flex recall today, 22 May 2026. Approximately 4 hours after dropping the trailer off the dealer called and said that the technician found significant frame flex and that the unit was unsafe to be towed. No other information was provided. I did ask for the measurements that the TSB 24-001 requires to be filled out ans submitted to Grand Design. The lady that called was completely unaware of what I was asking for.

   NHTSA complaint #11739591 · source
5. Filed Mar 30, 2026WIBody & StructureOther / Unknown

   The contact owns a 2021 Grand Design Recreational Momentum. The contact stated that while hauling the RV and driving at undisclosed speeds, the rear side door unexpectedly opened and the slide-out extended outward. No warning light was illuminated. The trailer was taken to a local dealer and remained with the dealer for additional inspections. The RV was not repaired. The manufacturer was made aware of the failure. The failure mileage was unavailable.

   NHTSA complaint #11727885 · source
6. Filed Feb 25, 2026WABody & Structure

   My Grand Design Momentum fifth wheel trailer is experiencing frame flex and structural integrity failure. The unit has developed spider cracking in the exterior fiberglass, interior wall separation, and plumbing issues believed to be caused by frame flex. The dealership has acknowledged structural concerns and installed lag bolts, but the underlying structural defect remains. Grand Design has denied that the frame flex caused the structural damage. This creates a serious…

   NHTSA complaint #11720529 · source
7. Filed Nov 17, 2025ILBody & Structure

   The contact owns a 2021 Grand Design Momentum RV. The contact stated that while inspecting the RV, the contact became aware that the outrigger brackets were bent and fractured. The contact stated that the failure was visible over the axles. In addition, the welding on the cross-member beams was fractured, causing the floor to crack, and the exterior fiberglass was cracked by the bedroom slide-out. Additionally, there was a four-inch-long crack on the frame of the upper deck.…

   NHTSA complaint #11699857 · source
8. Filed Oct 29, 202515,000 miOKBody & Structure

   The contact owns a 2021 Grand Design Recreational Momentum RV. The contact stated while driving 55 MPH, the RV frame flexed. The contact stated that when the RV was loaded, the failure persisted. The contact stated that the screws to the bedroom slide out were detaching. Neither an RV dealer nor an independent mechanic was contacted. The vehicle was not taken to a dealer or an independent mechanic to be diagnosed. The vehicle was not repaired. The manufacturer was notified…

   NHTSA complaint #11696350 · source
9. Filed Oct 27, 2025FLBody & Structure

   excessive frame flex/failure, Interior cabinetry coming cracked and apart. Floor separating from side walls. Main door coming open during transit.

   NHTSA complaint #11695772 · source
10. Filed Sep 3, 20256,000 miORBody & Structure

    The contact owns a 2021 Grand Design Momentum RV. The contact stated while the RV was parked and occupied, or while driving the RV, there was an abnormal popping and creaking sound coming from the frame of the RV while depressing accelerator pedal or depressing the brake pedal. Neither a dealer nor an independent mechanic was contacted. The contact stated that while driving the RV at an undisclosed speed, the doors opened independently. Additionally, while walking inside the…

    NHTSA complaint #11684821 · source
11. Filed Aug 20, 2025OHBody & Structure

    The contact owns a 2021 Grand Design Momentum RV. The contact stated that the RV had experienced a failure with the frame, causing the RV to become unstable while being hauled. Additionally, the frame was positioned on the pin box inside the unit, and the lag bolts and screws loosened, causing damage to the interior cabinets and trim. The RV was taken to the local dealer, who replaced the bolts and screws, but later, while using the RV, the failures reoccurred. The RV was…

    NHTSA complaint #11681767 · source
12. Filed Aug 18, 20258,000 miWABody & StructureSuspension

    The contact owns a 2021 Grand Design Momentum. The contact stated that while the trailer was parked, the contact became aware that the axle on the trailer had become inoperable. The contact stated that the axle springs had detached, and the I-beam frame of the trailer was bent. The trailer was taken to an independent mechanic, where it was diagnosed and determined that the axle springs and the frame had failed and needed to be replaced. The trailer was not repaired. The…

    NHTSA complaint #11681297 · source

Source: U.S. National Highway Traffic Safety Administration (NHTSA) Office of Defects Investigation public data. Complaints are submitted by owners and are not verified by NHTSA or by us; a complaint does not prove a defect exists. View this vehicle on NHTSA.gov Methodology