Saturday, September 23, 2023


RV Review: Grand Design Momentum 21G toy hauler

I had mentioned today’s reviewed Grand Design Momentum 21G when we looked at the Jayco Jay Flight Octane 277 recently. The first time I saw this floor plan was two years ago in Quartzsite and, what do you know, there it was again. And, like last time, this trailer really does strike a great balance between size and functionality. 

Grand Design Momentum 21G

This toy hauler is, as I wrote about the Jayco, what you would describe as a real toy hauler by the traditional definition of such. It has a higher roof, is 101” wide, and the Grand Design features a raised floor so there are no wheel wells in the interior. There is also a 30-gallon fuel tank to refill your toys. That same fuel tank can be used to provide sustenance to an optional Onan 4Kwh generator.

You can flip up the back couches such that you can fit a side-by-side or a golf cart in here. That would include those golf carts I see at the FMCA conferences with all the crazy decorations on them. And horns. 

The garage extends 78” at the full interior width, and there is plenty of space past the kitchen cabinetry for gear depending on what all you’re bringing along. If this isn’t long enough, Grand Design makes this same model available in longer versions as well, with the principal difference being the size of the garage. 

Almost 5,000 pounds of cargo carrying capacity

With almost 5,000 pounds of cargo carrying capacity, you won’t have to be as concerned about the weight of those toys. However, you should always be cognizant of the weight of your vehicles. But, still, compared to the few hundred pounds of weight in some RVs, this is where you should be if you plan to haul around heavy things. 

Like a Harley or two, for example. Or those golf carts. 

Grand Design

I’ve remarked about how many RVs are essentially adaptations of others’ floor plans. This is the same floor plan as the Jayco we looked at. So why buy one over the other? 

Despite being very similar on paper, there are some absolute differences. But whether these differences matter to you is another thing. 

Grand Design’s frame design on their Momentum toy haulers features a wide main build. That means there is less weight on what are called outriggers. Those are extensions of the frame that extend out beyond the main structure. 

I have bent outriggers on the frames of trailers, so the shorter and stronger these are, the happier I would be. 

By locating the heavy duty 12” I-beam main rails further outward, more of the floor assembly/unit structure sits on the heart of the chassis instead of the outriggers. Wider rails also create a more stable jack stance. They also allow for the slide room gear mechanisms to be enclosed inside the frame rails (rather than outside). This solid design means that the garage area of every Momentum is rated for full GVWR capacity.

Detail differences between the Momentum and Jayco’s Jay Flight Octane 277

There were also some detail differences between this and the Jayco. For example, I liked Grand Design’s cabinet detailing, lighting and upholstery choices much more. 

Grand Design also makes a lot of noise about their air conditioning system. The company claims their system offers more even air distribution. I haven’t been able to confirm this, although the company is also really straightforward and I have no reason to doubt their claims. 

I was also pretty surprised at the quality of the mattress. You can almost use this without some major changes, which isn’t true of a lot of RV mattresses. Like all the models in this floor plan, this one features a bedroom slide room which has the mattress in a slide. However, that mattress has to split about one-third of the way up. But this shouldn’t make a difference to those of us who are not royalty. 

Another plus is that this is a proper queen-sized mattress when the slide is out. 

Less awesome

But where the Jayco absolutely excels is in things like their Magnum Truss roofing system and the fact that they’re using Goodyear Endurance tires. If I were to buy the Grand Design it would only get towed as far as the closest tire dealership so I could get rid of the factory tires on the trailer. But that’s just me. 

I also like Jayco’s JaySMART™ lighting, which flashes the marker and side marker lights with the turn signals.

Boondocking and travel access

Trailers like this are fantastic for boondocking. Even without the optional generator, you have 100 gallons of water and a frame and build that can actually haul this much water around. I’m not suggesting that you make a regular habit of traveling with 800 pounds of water aboard. But the trailer will have no problem traveling with that much weight from wherever you get the water to the campsite.

The back portion of the trailer is fully accessible with the slide room in, unless you’ve stuffed it full of toys. But that’s on you.

Easy bathroom access in the Momentum

You can also get to the bathroom easily through a door that opens into the main body of the trailer.

There’s also a second bathroom door that opens into the bedroom. But don’t expect to get to the bed unless you’ve put the slide room out. Unless you do that, the folded mattress will do whatever it can to keep you out.

There are two choices of refrigerators: a traditional propane-electric RV fridge or a 12-volt DC compressor fridge. If you choose the 12-volt model, you get a 175-watt solar panel, 30-amp controller with inverter prep. There is also a solar option that includes a 300-watt solar panel, 50-amp controller and a 2,000-watt inverter.

In summary

Comparing this to the Jayco we looked at, which would you choose? I think either rig would be a comparable choice. But the Jayco has some features that will matter to some, the Grand Design has prioritized other things. 

There is no disputing the fact that Grand Design has really done a great job of building its brand and establishing a positive relationship with their customers, and there’s a lot of value to that. 

Another thing about “true” toy haulers

Their ceilings are higher to accommodate taller toys such as side-by-sides. But that also translates into significantly more headroom overall—and particularly in the shower. For taller travelers, this might be a great model to consider. 

I remember when I had the  Forest River Shockwave 24QSGMX on the lot and thinking it had a lot of value at about $42,000 that we had it priced at a couple of years back. So it’s surprising to see the Grand Design with an MSRP of almost $25,000 more than that. But this is Grand Design’s MSRP and our dealership did a lot of heavy discounting in those days. 

While I also think the Grand Design is a far better product than that Shockwave, this just points to how expensive RVs have gotten in these days of limited supply and crazy demand. 

But this is a nifty floor plan that can serve a lot of needs without being too big, while still offering lots of gigantic features. 

Which would you go with?

So which would you go with – this Grand Design or the Jayco, and why? We have our forums where you can share your reasoning. I’m certainly curious. 

I would love to read your comments and suggestions over on our new forums, where you can weigh in and start or join a discussion about all things RV. Here’s a link to my RV Reviews Forum.

Tony comes to having worked at an RV dealership and been a lifelong RV enthusiast. He also has written the syndicated Curbside column about cars. You can find his writing here and at StressLessCamping where he also has a podcast about the RV life with his wife. 

These RV reviews are written based on information provided by the manufacturers along with our writer’s own research. We receive no money or other financial benefits from these reviews. They are intended only as a brief overview of the vehicle, not a comprehensive critique, which would require a thorough inspection and/or test drive.

Got an RV we need to look at? Contact us today and let us know in the form below – thank you!



Wider frame
Simple suspension


The Grand Design Momentum is a traditional toy hauler that offers some terrific boondocking credibility along with nice cabinetry that is above the average in this field.
Tony Barthel has been a life-long RV enthusiast and travels part-time with his wife where they also produce a podcast, write about RVs and love the RV lifestyle.



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The Grand Design Momentum is a traditional toy hauler that offers some terrific boondocking credibility along with nice cabinetry that is above the average in this field. RV Review: Grand Design Momentum 21G toy hauler

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