Review: Grand Design Momentum 399
As we mentioned in the video, we wanted to do a written review of the Grand Design Momentum 399 so we could continuously update and be more thoughtful. This way, it will be easier to answer questions and update too.
Let’s start with the biggest pros, cons and would we buy it again?
- It’s stunning and everyone loves it!
- A second bathroom (we should stop here)
- Side deck for working out, wet dog or just chilling out
- 3 axles for higher weight capacity, which means full water is not a problem
- 3 AC units keep the rig cool on hot days
- We never run out of hot water with a 12 gal hot water heater
- The shower is great. Everyone invites us to their house for “nice hot shower”, we have one 🙂
- The onboard gen is a “Get out of jail free” card
- Easier to maneuver than people think. With a long bed truck, 92-degree turning radius
- With the Kodiak Hydraulic Brakes, it stops on a dime
- Unlimted power with the Battle Born Batteries setup
- It’s big so it’s always on your mind
- Toy Haulers are not as “homey” as other RVs
- Height is always a concern when driving
- More axles, more tires, more money
- The Lippert One Control is a pain to operate
- More systems, more to keep up with
- Setup and teardown take longer
- The 399 does not have access to the master bedroom or fridge when traveling
- The curved master bed requires a custom mattress
Would we buy the Grand Design Momentum 399 again?
Short answer: Yes.
Medium answer: We think a Toy Hauler is best for a couple with a motorcycle or a couple that wants a large office in the back. Using it as a “teen hauler” has some drawbacks. First, the garage becomes a collect-all/storage area and combined with the kids living quarters, it seems to always be messy. If we were to do it again, we would find a large 5th wheel bunkhouse and remove the jungle gym that RV manufacturers like to install and replace it with two standard twin beds (like I love Lucy) and a small end table in the middle with a lamp. If you have younger kids or Grandkids, the standard bunkhouses are fine, but when kids get over 5.5″ the narrow bunks and low headspace becomes a problem (for fulltime usage). Weekend trips are fun and no one cares!
Long answer: We have had good luck with Grand Design. They handle warranty issues quickly and have an easy to use customer service email. We have had parts mailed directly to us at RV parks and installed ourselves. They have even offered to reimburse us for mobile techs to avoid going to a dealer.
When traveling with a large rig, it requires a lot of attention. If you’re the kind of RVer that enjoys the RV as much as the destination, this is not a problem. But if your RV is just a means to go hiking, visit National Parks, etc. then you might not enjoy “dealing” with your RV so much. With that being said, I enjoy fussing with the RV, t0wing it and appreciate that aspect of RVing too. If you’re willing to travel with a big rig, then you get to enjoy more space when you arrive.
Some people commented that this season seemed fatiguing for us. Yes, between getting stuck in the mud, getting caught on telephone wires, almost breaking our stabilizers and doing all the upgrades… there was a lot going on. Yet, this is what happens when you travel fulltime. It’s no different than the 3 flat tires we had during Season 1, losing Caleb’s laptop to a slide leak, dog tracking to Mexico with a missing center pin, resecuring our front end cap on, or almost dropping Grand Ginger because I forgot to lower the tongue jack.
RVing is the best way to travel because we have our own bed and coffee maker, but it’s also an adventure. It can be dangerous if your head isn’t in the game and that’s what makes it exciting. The reason we change RVs so frequently is so we can stay in “learning mode”. Learning and sharing is what keeps us interested.
Toy Ginger and the Ford F450 have already been sold to a nice couple in OR that is going fulltime and running their business from the road. We couldn’t be happier that this amazing RV is going to long-time subscribers.
Season 8 starts on January 12th with a reveal video of the latest Ginger! Stay tuned. It’s going to be a great season… with more learning!
Complete List of all Toy Gingers Upgrades & Modifications
On this page, we’ll be sharing all the upgrades we complete on the 2019 Ford F450 and 2019 Grand Design Momentum 399TH. As we mentioned in the video, we’ll be using Toy Ginger for the duration of Season 7, sharing what we learn, debugging any issues (and there’s been a few), adding the upgrades and then selling the entire rig at the end of Season 7!
We don’t know if this plan is 100% sustainable yet, but as you have seen, we act quickly on our crazy ideas! Already we’ve learned so much about GPS route apps and Tricia has created all sorts of new organization ideas for the RV. When we’re in “learning mode”, we’re sharing even more; making the process of documenting our travel that much more rewarding.
The first decision we had to make was which 5th wheel hitch to use. Because we’re new to fifth wheels and Toy Ginger’s GVWR of 20,000 pounds, we elected to go with the B&W Companion hitch with the OEM puck system. This is what JD from Big Truck Big RV recommended and etrailer.com also thought it was the best option for us.
Pros & Cons: Now that we’ve been using the hitch for 5,000 miles, I love the sturdiness and simplicity of the hitch. There is ZERO play and connecting/disconnecting is a breeze. What are the drawbacks? If you’re not full-time RVing, you may not be willing to give-up the bed of your truck. It takes me about 5 min to remove the hitch from the bed. For even faster removal, you can look into the B&W Companion hitch that connects to the turnover ball or use a gooseneck hitch. Whichever hitch you decide to buy, be sure to check the weight ratings.
We have an affiliate link with etrailer.com. When it comes to big purchases for the truck and RV, we wanted to provide a resource that not only supports the KYD community but provides additional support and education.
ProClip Cell Phone Holder
This item came highly recommended through the comments and now I know why! This is a solid phone holder from ProClip. This is not an affiliate link, but KYD10 will save you 10%. They are a bit pricy compared to generic models, but because each cell phone holder is custom to your phone and truck, they actually work.
There are a couple of models to choose from and I suggest not getting the angled one. There is still plenty of angel with the model that faces forward. It does look a bit bulky with the bar that goes across the dash, but it’s not a problem.
WeatherTech no-drill mud flaps
Depending on your state, mud flap on dual-wheel drive trucks are required, but regardless mudflaps are a good idea and the F450 looked naked without them. I wanted a streamlined factory look and the WeatherTech no-drill mud flap was the best option.
These mud flaps fit perfect using the existing holes and no drilling. Be sure to add your truck to the etrailer website and find the right pair.
BAKFlip MX4 Hard Tonneau Cover
The BAKFlip tonneau cover is one of my favorite upgrades. I was very eager to get it installed on the new truck. Not until we got a 5th wheel did we know about the drawback not being able to see the hitch (from over my shoulder) when backing up.
This makes the BAKFlip MX4 my favorite bed cover for a travel trailer, but probably wouldn’t get it again if I had a 5th wheel. Which says a lot because I really love these bed covers. The fact is, the 5th wheel cam just isn’t adiquite and more times than not is overexposed due to the angle of the sun. I’ll be doing some reserch on the best bed cover for 5th wheel towing and post to our etrailer.com page.
Airlift QuickShot Compressor System for Air Springs
As I mentioned in the video, the Ford F450 only squats a little even with a heavy load, but I wanted the truck and trailer to be perfectly level. I also wanted on-board air to make adding air to our 12 110 PSI tires easy.
I was very happy with the install that Max-Bilt did in Eau Claire, WI. The location of the air switch in the upper glove box is perfect. The only thing I’m not pleased with is the Schrader valve appose to a quick disconnect with my previous ViAir system. If you don’t have the need for on-board air, consider the ViAir pump which is small and highly effective for tires over 65 psi.
TST Tire Pressure Monitor System
The Ford F450 doesn’t come with a built-in TPMS system. We use the TST TPMS system from TST provided by TechnoRV. This system allows us to add all six tires on the RV and the truck and the tire pressure for each tire are displayed on a color screen on our dash. As we drive, each tire rotates through on the screen. If there is a problem or the tire pressure falls below or exceeds the parameters I set, an alarm will sound.
This is by far the best TPMS system we’ve used and we’ve used them all. The cheap ones simply are not reliable and others are not easy to use. If you buy a TPMS system from TechnoRV, you’ll receive instructional videos on how to set up and install. They will also provide support should you have any issues.
Aire-Flow Moisture Barrier by Mattress Insider
First of all, don’t forget that Mattress Insider provides the KYD Community 10% off with the promo code KYD10.
We heard in the comments during Season 1 that due to the varying temperatures in an RV that moisture or even mold can build below a memory foam mattress. The Aire-Flow Moisture Barrier prevents that. It comes in a roll and you can cut it to size.
50 Amp Surge Gaurd
We stared with a cheap Camco surge protector when we first started and worked our way up. Considering all the electrical systems in a Grand Design Momentum 399, total protection is key. The Surge Guard is the best and completes an analysis of the connection for 10 seconds prior to sending power to your RV
Lithium Battery Solar Upgrade
We kill lead-acid batteries. We don’t want to, but managing distilled water levels just isn’t on our mind when traveling fulltime and making videos. We also don’t do a good job keeping the battery above 50% capacity. These worries are gone when upgrading to Lithium. Yes, Battle Born Batteries are $1,000 each but if you plan on keeping your RV for a while, you’ll avoid paying for lead-acid batteries two or three times over. *Maybe you’re better at maintaining things than me!
We also added 1,200 watts of solar on the roof with a 3,000 watt Victron Mult-plus invertor. You can watch the install video here.
Kodiac Hydraulic Brakes
Electric brakes are essential when towing – no matter how big or small the RV, but they are jerky and often break. Not to mention get brake dust everywhere making your wheel black.
We installed Kodiak Hydraulic brakes and they are smooth and far easier to maintain while increasing your stopping power tremendously.
This is one of those upgrades that bring a smile to face each time you press the brake pedal. To see the entire install video click here.
This is one of those upgrades you can’t believe you ever lived without, especially if you have a family, travel with dogs (safety), or your party gets split up. On many occasions, one of the boys will decide to go back to the RV early only to forget the RV keys. It’s frustrating and completely avoided by the RV Lock. Not to mention that many RV keys are the same and don’t provide a great deal of protection.
If you travel will dogs, many RVers leave their phone number on the door in case there is a problem. Should the power go out, you can always call a neighbor or the RV office and give them the code to get into your RV. You can get the RV Lock on our Amazon Page under the category “our fav RV items”.
Dometic CFX 95DZW 12v Electric Powered Portable Coole, Fridge Freezer
Grand Ginger (our previous Grand Design Reflection Travel Trailer) had an outdoor kitchen with a separate electric fridge. RV fridges that run on propane have proven to be finicky – not having a back-up fridge can cost hundreds in spoiled groceries. With the Norcold fridge not working in Toy Ginger (Grand Design Momentum 399TH), we needed a back-up fridge ASAP and the Dometic 12v Cooler is 100% reliable. When we get the Norcold fridge working properly, we will covert the Dometic cooler into a half freezer half sparkling water fridge 🙂
Extra Large Canvas Shoe Pockets for only $19.99
Most shoe holders for RVs are low quality or not big enough. These are great! They come with large gromet holes and hardware and the shoe pockets are large enough for mens sneakers. This is the second time we’ve bought them and thrilled we found them online at Overtons.
When we first got Toy Ginger and needed stabilizing feet, I was going to get the large Red Anderon buckets, even though I was reluctant because of how much space they would take up. Then I learned that they were almost $300 and quickly found a far better solution. The SnapPads are permanent feet for your stabilizers which means there is one less thing to do when setting up and tearing down. It’s not a bad idea to carry some square wood boards should you need to add height, but that is only required a fraction of the time. More times than not, you can simply just lower the stabilizers and move on
Not so small print about our Affiliate links:
*We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites. This page also includes affiliate links to our partners. Everything is 100% private and you don’t pay anything more.
Now that you have a big rig, will you also be getting a rv GPS system? It has the height you can add so it can tell you what route you can take, and to avoids roads you can’t take.
We’ve been using TruckMap and really liking it.
Ramona Westfall says
Have learned so much from your videos, thank you!
You mentioned your blackout shades but I am not seeing any info on them, would like to check them out.
Please provide some details.
John Vandenberg says
Why sell the rig after season 7. You are putting a lot of mods on and have the right truck for the size of trailer.
Perfect combo, keep it and your daydream!
We just wanted to experience and share a big rig for a bit. Who knows what will happen, but I suspect we’ll go smaller. I enjoy talking and recording the upgrades.
John Vandenberg says
That is a massive trailer for sure. Watched the Wilderness episode and that trailer is HUGE,
If you scale down go to the 328 or 351. It looked like a lot of tension hauling that size of trailer compared to the 312
We are very excited about this season and learning with Toy Ginger as we are thinking about upgrading to a toy hauler so that my wife can finally get herself a golf cart (plus bikes). We were initially thinking a travel trailer toy hauler, but that all changed when we saw you pull that 90-degree turn in the latest episode…..my wife and I just looked at each other and was like, “did you see that”!
I noticed that you stopped using the Rock Tamers? I added them after you talking about them on your show. We have a Momentum and the really keep the grime off and rocks from getting to the RV. Any reason you stopped using them?
Hey there guys, first off I love your channel and am learning so much from you. I just wanted to comment on the goose neck option for 5th wheels. Some manufacturers forbid using a gooseneck hitch with their hitch system. It puts a lot of stress on the frame I guess and they are usually not designed or built for it. The 5th wheels that can use the gooseneck conversion must be built up to handle the added stress. I would check wth the manufacturer before diving in. Anyhow, just my 2 cents, have a great day.
My husband and I decided to make Alaska our retirement trip, we have been to Alaska twice before on cruises, and have RV’d to all lower 48 states. Those were on extended vacations while working. A friend recommended your YouTube channel and so glad she did. We left home May 5th, from Central California. First destination was the 150th anniversary of the Golden Spike, Transcontinental Railroad in Utah. After that it was just go north. We were traveling with my husband’s elderly 2nd cousin (81 years young). This was their 3rd trip. 2019 has been fraught with fires and a lot of camp grounds full, without reservations. Our family had to split in Fairbanks, she had a bad reaction to the smoke. We toughed it out a week. Took an Artic Circle tour, and actually had to drive through fire, on both sides of the highway. Of course it makes for a good story now lol. We have enjoyed watching your videos, and re-watching to write stuff down. Couldn’t get into the Lil Mermaid, in Homer, for dinner, but had a great lunch! Since we are on our own, decided to put Haines off 2 weeks and check out Valdez too. Safe travels and thanks for the videos. I know a lot of work goes into them. We had a 27 foot 5th wheel and FordF350 for 20 years, bought a 32′ Fleetwood A class, gently used, 6 years old and 11k miles on it. Doing that, we are not RV poor and allows us to travel when we want. We have 2 cats that travel with us, one willingly, the other is on meds, everyday…even at home. I didn’t like transferring them from the truck to the RV. You don’t even have to go outside, when you park for the night.
Elena Akkasha says
Hi Marc and Trish,
I have a question regarding the twin bunk in the 399. We have a 9 year old who didn’t like the feel of the mattress. I think Carson sleeping up there. How is he sleeping on that teddy bear mattress or did you find a good replacement yet?
Hi Marc & Tricia,
Just started following you guys and really enjoying “your story”! Especially about Toy Ginger and your manly F450…really cool.
We are thinking about up sizing when we start our extended U.S.A travel when I retire (or slow down my work schedule). We currently have a Flying Cloud Airstream & Ford Expedition that we use to travel around Texas to various Rode & Gravel bike riding events. My wife likes to call it “glamping”:-)
Keep up the good work and will stay tuned!
All the best from Texas
Henry Zoch says
Marc, what kind of power do you use when you are parked, lets say at a friends house.
We have a “dog leg” I think they are called that converts 50amp to 110 to plug into a house. However, with our lithium/solar we have now, we don’t plug-in any more. 100% indefinitely sustainable. We bought a big box fan so circulate the air to avoid running the AC (and gen). We can run the AC on battery for about 5 hours, but only the living room AC, which is not enough to cool such a big rig. Big fan works much better.
John Hess says
That’s very cool. How many amp-hours of lithium do you have in the toy hauler? Did they all fit up in the front exterior storage area or did you put them somewhere else?
John Hess says
Which video shows where you couldn’t see the 5th wheel hitch through the F450 camera while hitching up? I wanna see that shot again. Is there a different tonneau cover that would avoid this problem?
E. Gilder says
I have not seen the video, but I have a F450 also and we installed a “Roll-n-Lock” cover and have not had any problems with our cameras when connecting our 5th wheel. Great product and support from the company.
Pat Costa says
Just saw the latest video and I really want more info on the truck battery wire you put in. Can you give ma a link? Been following you for a very long time. Thanks for your videos.
Jennie Henicke says
Hi guys! Did your Norcold issues get resolved? If so, what was the final diagnosis? We just got a brand new 5th wheel and the Norcold is not working.
The dealer has tried a couple of things but nothing is working. ????
We never figured it out. The entire fridge was replaced.
You had amazing patience with the Norcold / Grand Design – and then didn’t even mention it in the review!! It’s those kind of stories that have so far had me avoid a new RV – not that the used ones have been so reliable!
Jacob Miller says
watching the Alaska trip with the f-250 and reflection….. Would the F-450 and momentum 399TH make that trip?
Jacob Miller says
referring to the size of trailer and truck, would it have problems getting into the same places yall took the refelction.
We haven’t been in a situation yet where we couldn’t go. But then again, we’ve been in the heartland. It does require more energy and thinking.
Not only would it have made the trip, it would have made it better! More axles is better for carrying more water and the on-board gen means we would have dry-camped more, even when raining. It would have been easier to protect the rig from rock chips with a 5er.
Jacob Miller says
about the generator and dry camping……have you had any instances where you bothered people around you running it all night or day when required? or even places where it wasn’t allowed? we have wanted to take a summer trip to Colorado to get out of this south Texas summer heat. while the onboard onan is pretty quiet, I don’t want to be THAT person making the noise.
Dwayne Lee says
You did a review of the installation of the Rock Tamers Mudflap. I haven’t noticed it in your recent videos since you got your 5th wheel. I have a 41′ 5th wheel that is always getting mucked up with road tar, etc. I was going to order the Rock Tamers before are 1st trip this spring (we’re not full timers and live in MT, so have to winterize after our last trip in October). I’d like to hear your experience with it before order it.
Eric Hakanson says
Now that you have a BIG trailer, I’d love to see a table with all of the weights, including:
* The door sticker on the F450 that shows the actual GAWRs (as well as the allowed payload)
* The listed GVWR & GCWR for this model
* The actual weights on each axle, unloaded (with either empty or full full tank), and fully loaded.
* How close the latest Ginger is to its GVWR of 20k pounds.
I’ve been looking at an even larger trailer, and am concerned that the pin weight and other cargo might exceed the rear GAWR of an F350 or F450. But the GAWR isn’t published, and the actual weight is dependent on model & accessories, so you have to look at a truck to tell. Seeing a complete analysis on a heavy trailer would be helpful!
Denis Shelston says
Heard you mention briefly this week (Dec 16) that you’ll have a different truck soon…
Do tell… I missed something.
Keep up the great work, love your channel.
Many people missed our intro when we first got the “big rig” that it was just for SN7. It does seem like a lot of work for just a single season, but the videos are a lot of work too!
Kenny and Kay says
You mentioned the breathable mat for your custom mattress, can you provide a source?
Thanks for the awesome videos.
Here is the link. I’ll update this page too. http://bit.ly/Mattress-Moisture-Barrier
Not sure this is the right spot to ask a question. I thought I’d watched every episode of your travels in Toy Ginger, but I haven’t caught one with the “walk thru” ?? Is there a particular episode that I could check out? It is on it’s way out I know, but just curious. Totally enjoy your videos, they are great and quite professionally done. You two do an excellent back and forth between you when narrating. Look forward to……………..I’m guessing………………a motor home! Thanks Monte (Olympic Peninsula – Washington State) P.S. I RV vicariously through YOU! 🙂
We just bought our very first RV and we went big of course! ???? We purchased a 45’ Seismic toy hauler. We don’t have toys or boys, but we have a teenage daughter that shows lambs in FFA so the hauler will be for a lamb pen to take to big shows. This episode and blog have been so helpful! I look forward to going back and watching all the episodes in Season 7!
Lamb hauler? That’s awesome 🙂
Stephen Simms says
Hello Marc and Trish and Happy New Year to you both.
I simply wanted to thank you both for all you do for the RV community. Marc I emailed you with questions this past fall and you were very gracious to respond so quickly. You guys are really awesome folks. We wish you both an amazing 2020 and season 8. We are looking forward to seeing your new rig come January 12th.
This past fall we bought a 45 foot Jayco NorthPoint with a small enclosed garage for the Harley and full living space with a front living room/rear bedroom setup. We’re only just getting going with our RV journey and not F/T but in 2020 heading to Tucson, Palm Springs and Monterey from late Feb thru April.
Thanks again for all you do. You’re very much appreciated by us and from what I read, thousands of others.
Stephen & Leslie (Alberta, Canada)
Thanks Stephen & Leslie!
Hello Marc & Trish,
Now that was one beautiful rig, both truck and fifth. My question is about depreciation on resale. Do you have any comments regarding your strategy to purchase the rig, fit it out only to sell it after the season. Did outfitting the rig offset the large first owner depreciation at all? Of course one would not expect to use the rig for a year for free, there would obviously be a cost associated with travelling with this caliber of accommodations that would be factored in. It would be great if you could share your experience.
All the best in S8 & 2020.
Hi Wayne, We’ve learned to stick to *towable* RVs that are in high demand and buy them 30% to 35% below MSRP. This offsets tremendous depreciation, if not most all of it assuming the RV is like new when it’s time for sale. Candidly, we are in a unique situation working with our partners to add even more value like solar and brakes to offset the depreciation entirely. We decided to switch RVs more frequently so we can get as much experience as possible and eventually make comparison videos.
Did some searching and can’t find the laptop desk you use. I would love a video that included “work set-up” in the RV and what tips/tricks you have for that.
lisa Thompson says
hi guys, I am completely new to this world, and your channel, we are considering an RV @ retirement to do the national parks tour I’ve always wanted to do so I started watching your channel to try to learn something beforehand, one thing I find frustrating, is you throw out a lot of jargon like dry camping, mooch docking, etc, and I have no idea what they are, could you add a glossary page to your site for total newbies like me, please? I would appreciate it, thanks!
Joshua Ox says
I am personally curious about the back of the toy hauler and it’s comfort level. Every time I’ve walked through one I’ve always felt like it was cold and kind of uninviting. How are the temperatures back there especially when it really cold or hot out?
Christopher Kozanecki says
Season 7 with the big toy hauler is what got me hooked on you guys!! Keep up the amazing videos.
I recently bought a 44 foot 5th wheel to keep at a seasonal site for a few years till I get a truck to haul it. Loving the ram 3500 right now, but we’ll see when it comes time.
One question I have is whether you needed to get a non-CDL class A for that big rig? Seeing so many mixed reviews, and state to state variance it’s hard to know if I’ll be able to drive this thing? Would love your thoughts.
JON L POTTER says
in one of your videos you are talking about the Zero G hose, and you mention 2 hoses. One for Grey water and one for Fresh water. Can you explain the difference?
Would you please do this same type of article for the Airstream? Also a compare/contrast of all of your rigs in one article/video would be fantastic. Which one has been your favorite? We love our Airstream 26 RBT, but we are now going full time. We will be 9 months every year in one location, which has started us thinking about a Grand Design 397 or Airstream 33 Classic. Thanks.
Kris and Jen says
Hey Mark and Trisha!
Not sure if you still answer questions for the toy hauler now that the season is over, but we are on year 2 with our 399TH and we NEED to organize the storage better in the basement. Did you ever get a tray, and if so, which one did you decide on?
Jennifer Z says
We’ve been following you for a while now and are about to start our own full time living. Just got our F350 Super Duty Dually and put our deposit down for the build of our Grand Design 397THS! Thank you for all of your helpful information, especially when it comes to the Grand Design! Who knows, maybe we’ll see you on the road sometime!