AI Damage2021 Grand Design Momentum: common problems
Owners of the 2021 Grand Design Momentum filed 58 complaints with NHTSA, most often about structure and suspension. The maker issued 2 service bulletins for this year. Details by component below, with sources.
Key figures
- Owner complaints
- 58
- involving a crash
- 1
- Technical service bulletins (TSB)
- 2
What fails most often
- 1 Structure 72% of all complaints
- 2 Suspension 33% of all complaints
- 3 Latches, locks, linkages 16% of all complaints
- 4 Equipment 5% of all complaints
- 5 Service brakes 3% of all complaints
- 6 Electrical system 2% of all complaints
- 7 Exterior lighting 2% of all complaints
- 8 Powertrain 2% of all complaints
- Structure: 42 complaints (72% of all); manufacturer bulletins for this component: 2.
- Suspension: 19 complaints (33% of all).
- Latches, locks, linkages: 9 complaints (16% of all).
- Equipment: 3 complaints (5% of all).
- Service brakes: 2 complaints (3% of all).
Symptoms owners describe
How many of the 58 NHTSA complaints mention each symptom (automatic count from complaint text; one complaint can mention several).
Components owners complain about
| Component | Owner complaints | involving a crash | Technical service bulletins (TSB) |
|---|---|---|---|
| Structure | 42 | 0 | 2 |
| Suspension | 19 | 0 | 0 |
| Latches, locks, linkages | 9 | 0 | 0 |
| Equipment | 3 | 0 | 0 |
| Service brakes | 2 | 0 | 0 |
| Electrical system | 1 | 0 | 0 |
| Exterior lighting | 1 | 0 | 0 |
| Powertrain | 1 | 0 | 0 |
| Other | 27 | 1 | 0 |
What owners report
Short excerpts of NHTSA complaints in the original wording. These are owner statements not verified by NHTSA; personal data removed.
Leaf spring broke in half while traveling down the highway. Completely destroyed left rear tire by locking it up and causing it to drag for 1 mile before I noticed and could stop.
Upon returning from a recent trip I discovered that the passenger side rear leaf spring had snapped in to, near the rear leaf spring hanger. The equalizer also had cracked welds because of the incident. Thankfully the front of the leaf spring was still attached.
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.
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.
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.
The contact also stated that the frame of the RV was full of rust. The vehicle was not taken to a dealer or independent mechanic to be diagnosed or repaired. The manufacturer was not notified of the failures. The failure mileage was 6,000.
I am experiencing upper deck frame flex which our manufacturer has unsuccessfully attempted to repair twice (Nov 2021 and Oct 2024). The manufacturer refuses to accept responsibility for our safety concerns and has ceased all remaining repair attempts which was communicated to us through emails.
Main doors coming open - currently bungee cording , cargo doors coming open - currently bungee cording, slides coming out a couple inches, leaf spring broke during travel on interstate, open case with Grand Design since January 22, 2023, [ref] and Grand Design has not been helpful in addressing these issues.
When owners complained
NHTSA complaints by filing year. The peak shows at what age the problems show up most.
Comparison
By complaint count this model year ranks 4,955 of 36,656 model years in the NHTSA data (top 14% most complained about).
On average one model year of the Momentum has 18 complaints (12 years in the data). This year has 58, above average.
What to check before buying
- Structure. Rails, pillars, panel gaps, signs of pulling or welding.
- Suspension. Wheel alignment, control arms, subframe, even tire wear.
- Latches, locks, linkages. Door, hood and tailgate latches, especially near the impact.
- Service brakes. Pedal feel, ABS operation, leaks, discs and hoses.
Manufacturer service bulletins
Bulletin titles as filed with NHTSA.
- Grand Design is addressing concerns of excessive frame flex or wall securement in the front upper deck…
Grand Design is addressing concerns of excessive frame flex or wall securement in the front upper deck area of a limited number of fifth-wheel units. This condition could potentially occur over time due to a…
- TSB 24-001 Issued in March on March 7th. Concern
Complaint of upper deck flex which results in cosmetic damages to the interior and excessive flex at the pin box. Remedy : The procedure outlined in attached summary to assess damages if any and direct customers to the…
Other years of this model
Questions and answers
What are the most common problems with the 2021 Grand Design Momentum?
Owner complaints to NHTSA most often mention: structure, suspension, latches, locks, linkages. Total complaints: 58. The most frequent symptoms in complaint texts: overheating, coolant loss (2%), rust, corrosion (2%), warning lights, check engine (2%).
How many service bulletins (TSB) were issued for the 2021 Grand Design Momentum?
NHTSA lists 2 manufacturer service bulletins for this year. A bulletin tells dealers how to diagnose or fix a known issue; it is not a recall.
Should I buy a 2021 Grand Design Momentum from a US auction?
Owner complaints describe defects, not crash damage. Before bidding, check the components listed above and review the lot photos: VinWind builds a report of visible and hidden damage by VIN.
Other 2021 models
Read also
Sources: public NHTSA data (USA): service bulletins and owner complaints; YouTube: links to videos credited to their authors. Complaints are owner statements not verified by NHTSA, and describe defects rather than crash damage. Data updated 2026-11-05.