I’ve seen Gymrail’s Momentum X1 system popping in and out of my Zwift feeds for years, but only recently did I notice they were shipping to the US! So I reached out to get a loaner unit and Harri Salmenautio, CEO and Founder, replied. Soon enough, it arrived at my door from their home base in Finland.
How It’s Different
Gymrail calls the Momentum X1 a “4D bike rocker system.” Not only does it allow for 15 degrees of side-to-side tilt like a basic rocker plate, it also gives 12cm (4.5″) of fore-aft movement like some advanced rocker plates. On top of that, you also get 12cm (4.5″) of side-to-side sway and 7 degrees of twisting rotation (yaw) from the central axis!
To be clear: “sway” here is your bike being able to slide left and right without tilting. You’ll notice it most when really putting the power down, as the back of your bike slides left and right.
“Yaw” is when your bike twists into a sort of “s-curve”, again seen most when you’re putting down the power, perhaps out of the saddle. As you turn your bars one way, the bike tilts in the opposite direction. (This motion isn’t seen on standard rocker plates, but it is available on the InsideRide E-FLEX Motion System.)
That’s a lot of movement. But maybe there’s something to it. Because any physicist will tell you, the physics of riding a bike are quite complex. There’s a lot of movement going on to keep us upright!
Here’s a quick promo video from Gymrail, so you can see the basics of how the system works:
Unboxing and Setup
The MX1 arrived in a box that had seen better days, but when I unpacked it I quickly realized that nothing was going to break this unit. It’s built like a tank!
The system consists of two separate sections: one connects to your trainer and one connects to your front forks. Both sections require a bit of assembly. Gymrail’s website includes written and video instructions for assembling the unit, and I highly recommend using them.
The rear unit is basically a giant skateboard with added side-to-side sway movement. It comes fully assembled, but you need to mount your trainer securely to it and adjust the bumpers to your liking. To mount the trainer, you first position your trainer where you’d like it on the platform, then screw in the included steel plates beneath the trainer so you can secure the trainer to the platform via the included velcro straps. You’ll need a cordless drill to screw the plates in.
This setup worked swimmingly for the Zwift Hub I was using. The trainer was mounted very solidly thanks to the custom-placed mounts and sturdy velcro straps.
The rear unit includes rubber bumpers underneath which can be slid left and right to change how easily the platform tilts. Adjust these to your liking, but know you can always tweak them later (and probably will). Just get the platform level, then you’re ready to continue.
The front unit just needs the legs folded out and locked in with bolts, then the vertical “steering unit” attached using the included tool. The steering unit has rubber bumpers like the rear unit which you can slide left and right to dampen how easily the front of your bike tilts.
Dialing It In
Assembling the unit is one thing. Dialing it in is another. Without a movement platform of any sort, riders have nothing to adjust. Add a basic left-right tilting rocker plate, and you have the inflation of the balls to adjust (which is no small thing). Add fore-aft movement and you may want to adjust the stiffness (although that’s rarely adjustable).
Add two more types of movement, like the MX1 does, and you’ve got even more to dial in!
The first thing I noticed was that my front forks were too stiff when trying to tilt left and right out of the saddle. So I adjusted the bumpers on the steering unit toward the center, giving that unit maximum freedom to tilt. This helped, although things still felt stiffer than I’d like up front.
(I already had the rear bumpers moved toward the middle for maximum left-right tilting, since I ride rocker plates all the time and am comfortable with that “looser” feel. The rear tilt felt great from the start, so I didn’t need to dial it in further.)
The next thing I noticed was excessive “sway” at the back of my bike when sprinting. Some sway is natural, actually – your rear tire does “slide” left and right in a sprint. But too much sway and you feel like you’re losing power as the rear unit slides left as your right leg pushes down/back, then slides right as your left left pushes down/back. Changing from the installed black springs (the loosest included) to the orange springs (20% stiffer) helped the sway situation.
Here’s a quick video demo I made not long after getting things set up:
Ride Feel
One thing I feel reviewers miss when it comes to rocker plate testing is that you really need to give yourself enough time on a new rocker to ensure you’re actually feeling how it behaves, and not just feeling how it’s different from what you’ve ridden before. I ride with a rocker plate all the time, and have reviewed several rocker plates over the years. Every new rocker feels a bit odd when I start. It takes several rides to really get the feel for how the plate lets me move, and to fully understand if it’s letting me move naturally or inhibiting the movements I’d like to make.
After several weeks of riding with the MX1, I’ve come away with some things I really like about it, and a few things I don’t.
The Good
- It lets my bike move more than any other platform I’ve tested. The rear sway and the s-curve “yaw” are something you don’t get in typical rocker plates, and they really add to the natural feel, especially when seated. The MX1, much like the InsideRide E-FLEX, offers a more natural and comfortable motion than a standard rocker plate when it comes to seated riding at low and mid-power levels.
- Nothing to inflate: inflatable balls can be handy when you’re trying to customize the stiffness of a rocker plate, but there’s something really nice about a few sets of steel springs that you know will deliver consistent performance.
- Quiet: even though it has springs, it doesn’t have the fore-aft noisiness that some plates have. It’s a very quiet setup.
- Sturdy: yes, your bike can move a lot. But you know the unit isn’t going to break or fail in any way, because (as I’ve already mentioned) it’s built like a tank.
Needs Improvement
- I’d still like more side-to-side tilting movement on my front forks. I like the feel of standing up and being able to swing my bars left and right freely, but the steering unit, even at its loosest setting, still inhibited this movement somewhat.
- Too much rear sway: I wasn’t able to test the rear unit with Gymrail’s stiffest springs (red) since they weren’t included in the package, but the mid-stiff (orange) were still a bit to wiggly for me, and the least stiff (black) were definitely not stiff enough. It should be noted that this will be less of an issue for lighter and/or weaker riders. I’m 83kg, with a sprint that tops out at ~1100W. The heavier you are, and the stronger your sprint, the more you’ll notice and probably want to dampen the sway.
Lastly, I must mention that the biggest problem I had with the MX1 was that the rear unit would shift to the right slightly each time I put in a hard, out of the saddle effort. Even after putting down a mat to reduce any possible slipping, it still happened. Then I realized my problem: the floor wasn’t perfectly level!
So this isn’t a flaw in the MX1, but it’s something you’ll want to consider if your floors perfectly level. Because the MX1 uses rollers for fore-aft movement, it will work its way “downhill” if used on a floor that tilts left or right, even slightly. This isn’t a big deal if you aren’t out of the saddle sprinting much, but in a longer race, you may find the rear unit has shifted several inches to one side, which can be a real problem. (This, incidentally, is not an issue “normal” rocker plates have.)
A Word About Innovation
I want to be sure and give kudos to Gymrail, who have put in countless hours to develop a quality product for a very niche market. And they’re not done yet! Their website says they’re working on Zwift-integrated steering with the MX1, as well as braking. Keep up the good work, Harri and team!
Pricing and Availability
The Gymrail Momentum X1 is priced at €1,239.00/$1083, but on sale for €999. So it doesn’t come cheap, and feels especially pricey at a time when good smart trainers can be found for half that price.
Due to its price, I wouldn’t recommend it to every Zwifter. But if you’re looking for a well-built platform offering unprecented levels of motion, the MX1 may be just the ticket.
It is currently shipping to the EU as well as USA, Canada, Australia, and the UK.
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