2021 Grand Design Momentum

There was excessive frame Flexing in the nose section of our 5th wheel. I inspected the lag bolts in the front section of our 5th wheel that hold the wall to the frame and found 4 bolts missing of the 12 that are supposed to be installed. Also, the bolts that were installed were undersized. I also have damage to the inside wall and cabinets from over-flexing during travel. I have not contacted a dealer of the manufacturer but have been following many other individuals on forums who have had similar issues. I have not had my unit inspected yet, but plan to start the process with Grand Design. The warnings were trim pieces falling off after travel days and damage to the interior wall. I also replaced screws on the outside cap that loosened, and some fell out.

There are hairline cracks in the frame / Axle hanger(s), throughout the entire inside floor there are drops / gaps when a level is put down of a minimum of 1/8" - showing symptoms of frame flex / failure. On the road, the trailer produces excessive sway, bounce, and movement at speeds of 45 mph and above to the point where control has almost been lost on the roadway. It has been towed and tested with 3 different vehicles (2019 F250 Diesel, 2022 F450 Dually Diesel, and 2023 F250 Gas). documentation, video proof, Multiple witnesses, and different drivers all with over 7+ Years up to 30+ years' experience have tested this and have come up with the same results. Upgrades were made to both tow vehicle(s), Hitch(es), and trailer as suggested by Grand Design RV. Grand Design has stated after investigation that the axles on this unit were installed 5" out of the normal manufacturing of a Momentum 31G and there is a 1/2" difference between the driver's side front axle hanger and rear passenger side axle hanger. Trailer has been weighed multiple times with various loading procedures to make sure everything was evenly distributed side to side and front to rear. The trailer has not been overloaded yet the leaf springs were flat before upgraded to heavier weights. Tires have shown uneven wear patterns. Hitches have been set up in various positions per manufactures requests without any success. Grand Design has not taken responsibility nor attempted to fix the issues with the unit even with the proof submitted to them. Instead, they have been combative, dismissive, and try to bully their way out of their responsibilities. I've invested my own funds over the course of 3 years to attempt at rectifying the issue with no success. My family will not even travel in the same vehicle as me because they fear for their safety as I do as well as the safety of everyone on the roadway. This, however, does not concern Grand Design as they've unprofessionally stated to me consistently.

Our 5th wheel RV has had frame flex (frame failure) 4 separate times. The manufacturer has "fixed" it 3 times unsuccessfully. We have just owned this for 3 years and due to the length of time in between reporting to the manufacturer and waiting for repairs, the RV has been broken more than not during ownership. The pinbox is currently flexing due to broken welds on the frame and causes interior and exterior damage to the unit each time it is towed.

In february 2023 we noticed several internal (sawdust, exposed finish nails, floor noises, broken trim, pinched wall coverings) and external (multiple locked doors opening in transit)signs that our RV frame was experiencing excessive flexing, more than what is expected and necessary for a nearly 42' metal vehicle frame. The frame has since failed, the suspension is underrated for the weight of the vehicle. The manufacturers UVW and GVWR sticker knowingly contained incorrect OEM information with proof from a CAT scale leading to me as the owner believing the vehicle could have been loaded with more OEM item weight from the manufacturer than what was accounted for and annotated. Despite understanding the allowable weights and keeping this RV well under the advertised GVWR, the 6 separate leafsprings of the suspension are all flattened. The upper deck frame failed under normal on-road (and very little) use. A 2024 TSB was issued on my RV for "upper deck flex". .5" of movement at the pin box was the "within limits" passing grade. My unloaded and empty RV's measurement taken by an authorized service center by the manufacturer in keeping with the TSB, measured 1.5" of flex at the pin box. This failure was so great it led to the manufacturer instructing the Service center to not move it or release it to me out of safety concerns. It has been at the service center since 4/10/2024 ti present without any instruction or communication from the manufacturer on how to proceed either under warranty or otherwise.

Signs of frame flex/failure Lag boats through frame beam into exterior walls, are protruding and coming out. Countertop and cabinet, rubbing against the walls, lots of cracks in the Front Cap. The RV as less then 5000 miles on it and only used maybe once a month during summer months. Per my research these are signs of frame flex/failure.

We have a 2021 Grand Design 353G Momentum fifth wheel RV. We have experienced frame failure with the upper deck of the RV. It has been inspected and repaired by the manufacturer recently, but I wanted to let you know about this issue that seems to be prevalent in the RV industry. It seems that the manufacturer has under engineered the chassis that Lipper has produced for them. I feel that this repair will not be sufficient for the life of the RV. I believe this is extremely unfair due to the cost of these and the cost my wife and I have incurred during this ordeal. Frame failures seem to be at the forefront of issues currently and things need to change. We saw signs of failure up to a year before we had it repaired but did not know what we were dealing with. The welds on the chassis are poor and the quality control of these units are very, very poor. If these were to fail on the highway, lives are at risk.

The contact owns a 2021 Grand Design Momentum 397 Fifth Wheel. The contact stated that there were tears in the metal of the subframe. While driving at unknown speeds, the RV was bouncy. After connecting to a truck and towing the truck, the RV became unsteady. The local dealer was not contacted. The RV was not diagnosed or repaired. The manufacturer was contacted and referred the contact to the frame manufacturer. The contact called the Lippert manufacturer and was informed about measuring the distance of the subframe. The failure mileage was unknown. The VIN was not available.