2021 Grand Design Momentum Problems

What owners report

Owners of this model year most often report excessive frame flex in the upper deck or pin box, with broken welds, loose lag bolts and separating cabinets or walls. Cargo, compartment and entry doors opening during travel are also common and are often linked to frame movement, and some owners describe leaf spring or shackle failures. The few reports that state mileage fall between about 6,000 and 15,000 miles, and most reports do not state mileage.

1. 1
   Body and structure

   Frame flex, broken welds and structural cracks

   • 53 complaints (91%)
   • median 8,000 mi at 4.9 yrs old (3 state mileage, few)
   • 1 mention a crash, fire or injury
   • filed 2022–2026

   Owners describe excessive frame flex in the upper deck or pin box, with broken welds, cracked walls, loose or missing lag bolts, and cabinets, floors or walls separating from the frame. Some describe bouncing or unstable towing, and doors or compartments that open in transit. According to complaints, the dealer replaced bolts and a repair shop welded the frame, but some owners say the flex or damage returned, and the manufacturer in some cases stopped repair attempts or referred the owner to the frame maker. Where mileage is given, reports are between about 6,000 and 15,000 miles, and most reports do not state mileage.

   2 related service bulletins

   What to check: Ask the dealer whether the upper deck flex and pin box bulletins (TSB 24-001 and the related service campaign) have been applied, and request the frame measurements and repair records. Check the upper deck, pin box and interior cabinets for gaps, cracks and loose or missing lag bolts before buying.

   2 excerpts from owner complaints in NHTSA records

   “This trailer has frame flex in the gooseneck area to the point it is damaging the cabinetry in the front of the trailer. I have been in multiple momentum trailers with this problem and the dealership just wants me to trade it in or charge an astronomical amount of money to try and fix. It’s a known problem that everyone needs to be aware of.”

   NHTSA complaint #11556669, filed 2023-11

   “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. …”

   NHTSA complaint #11641945, filed 2025-02
2. 2
   Latches, locks and linkages

   Cargo or compartment doors open while traveling

   • 25 complaints (43%)
   • median 6,000 mi at 4.9 yrs old (1 states mileage, few)
   • filed 2024–2026

   Owners describe cargo, compartment, entry and slide-out doors opening while towing or driving, sometimes with items flying out or hatches not closing fully. Several complaints connect the door problem to frame flex or wall movement, and some owners say they used bungee cords or duct tape to keep doors shut until repairs were made. A complaint says the doors continued to open after repair attempts. The only mileage given for these reports is about 6,000 miles, and most reports do not state mileage.

   What to check: Check all cargo, compartment and entry doors and the slide-out latches for gaps, rubbing and loose hardware, and ask the dealer whether frame flex has been ruled out. Confirm that doors and latches were rechecked after any frame repair, since complaints link door problems to frame movement.

   2 excerpts from owner complaints in NHTSA records

   “This is an updated report with additional detail. Sorry for any confusion this may have caused. * Baggage door routinely open while travelling. A number of items may have been sucked out of the RV while moving down the road. We try to be hypervigilant and pull over as soon as we notice the door flapping open, and we secure loose items in drawers. * RV doors routinely open. The front door always opens, even though we use the 'deadbolt'. …”

   NHTSA complaint #11593059, filed 2024-06

   “After a trip we noticed that when we had the rv connected to the truck, the front closet would not close. There was also cracking on the nose cover of the rv. We (my wife and I) had a problem with the cargo doors and entry doors coming open on other trips and lost stuff on the highway so we talked to the rv dealer to get a frame inspection. what was found was that the frame was broke in a few places and the door side wall of the camper was not attached. …”

   NHTSA complaint #11641264, filed 2025-02
3. 3
   Suspension

   Leaf springs and shackle bolts breaking or detaching

   • 11 complaints (19%)
   • median 8,000 mi at 4.9 yrs old (1 states mileage, few)
   • filed 2022–2026

   Owners describe leaf springs that broke or detached, and bolts at the spring eye or shackle that sheared or broke. A complaint says the spring slid side to side, the axle was no longer held to the frame, and the failure happened on the freeway at about 65 mph. Another complaint describes a leaf spring that broke on the highway and locked up a tire, and a separate report found a shackle bolt broken in half. The only mileage given is about 8,000 miles, and most reports do not state mileage.

   Recall 26V044000Recall 23V490000

   What to check: Ask the dealer to inspect the leaf springs, U-bolts, shackles and spring-eye bolts, and confirm whether the listed leaf spring U-bolt recalls have been completed. When the trailer is unloaded, check for springs that slide, bent shackle hangers or gaps at the axle.

   2 excerpts from owner complaints in NHTSA records

   “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. This RV issue may be related to the widely documented frame flex issue. 1) The RV is at home in my storage shed. 2) Our safety and other motorists were put at risks because if the axle would have completely detached from the frame, it could have caused a catastrophic accident. …”

   NHTSA complaint #11767267, filed 2026-09

   “Left rear wet bolt sheared mid-bolt at the hole where the grease comes out to grease the sleeve in the spring eye. Spring was sliding side to side, causing the shackle hanger to bend and the spring to detach from the shackle. I have Summo springs on the trailer, and the one on the left rear took the weight of the trailer, and may have prevented further issue's. This occurred on the freeway at approximately 65 mph. …”

   NHTSA complaint #11540112, filed 2023-08

Buying note. Ask for records of any frame, pin box or lag bolt repairs, and whether the upper deck flex service bulletin has been applied and documented. Before buying, have a qualified inspector check the upper deck, pin box and suspension, and confirm whether the U-bolt recalls listed for this model year have been completed.

Summary written with AI from a sample of 54 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.