If you ask any cyclist what they don’t like about using an indoor trainer there are a few answers that you’ll always hear: “they’re loud”, “it's slow and difficult to mount the bike”, “they chew up my nice race tires”. We thought the same thing, and decided that there has to be a better way… And there is! We fixed some of biggest problems that cyclists have with current trainers by rethinking the whole concept of a bike trainer.
Enter the STAC Zero. It offers a zero contact resistance unit, which means no noise, no tire wear and even real power measurement! We solidly believe that it’s the world’s quietest trainer, and we welcome anyone that can prove otherwise.
The STAC Zero is a novel, unique trainer that can take your bike training experience to the next level. Have a small apartment with neighbours that don’t like noise? Have a family that doesn’t appreciate your early morning/late night training habits? Don’t want to swap out trainer tires each time that you want to go for a ride, but the weather isn’t cooperating? Have a mountain bike that sounds like a sawmill on a normal trainer? If you understand ANY of these problems, the STAC Zero is for you.
The STAC Zero is the quietest and one of the smallest, easiest to use and most portable power compatible trainers available on the market. The only noise generated comes from your bike’s geartrain, and nothing ever touches the tire, meaning that you will never have to buy another trainer tire. It was even designed to be used with knobby mountain bike tires!. With initial retail pricing set at $499 CAD for the power model and $399 CAD for the non-power version, it’s also some of the best value you can get in a trainer. To all the non-Canadian backers out there: remember how weak the Canadian dollar is right now, and what a great deal you can get on the trainer!
Technology and Development Status
The cornerstone of the STAC Zero is in its patent pending non-contact resistance mechanism. Although it may seem like magic, the secret is harnessing the power of magnetism. By moving an electrical conductor through a magnetic field, you generate a bunch of small electrical fields called eddy currents. This effect resists the motion of the conductor, and voila, you have a resistance unit! If you don’t believe us, try dropping a small rare earth magnet down an aluminum or copper tube, and watch how slowly it falls! (Or, if you don’t feel like doing that, watch the video below!). The amazing part is that the tube doesn’t need to be steel, it actually works better with aluminum or copper.
So, you may be asking yourself, that’s great if I happen to have a fridge magnet and a piece of aluminum tube, but how does this help me with my bike? Here’s how we decided to apply this concept: by keeping the magnets stationary and placing them near the wheel’s brake track, the wheel faces a resistive force that slows it down, accomplished without having to press a roller onto a tire or having to replace your rear wheel with a direct drive cassette mechanism. The faster you spin the wheel, the more resistance you generate. The closer you move the magnets or the more magnets you use, the more resistance you generate.
Current Technology Status
After a large amount of trial and error, we eventually settled on a concept that used a closing caliper to move the magnets near the wheel. This allows for virtually any tire size to be used, ranging from the narrowest road tires, to 2.25” knobby mountain bike tires, while the magnets can be placed sufficiently close to the wheel to generate enough resistance. The magnets are capable of generating more than 2000W* of resistance, and let’s face it, if you need more than that for a long period of time, you probably have a dedicated coach and training facility.
(*in theory, we can’t physically manage to hit that number!)
With hundreds of test hours on the trainer, we’ve been working on making the simplest possible mounting method in order to get you on or off the trainer as quickly as possible. A quick release lever is used to hold the magnet array at precisely the right distance from the wheel, which gets you in and out in seconds.
Power to the people
Due to the unique resistance unit, it’s incredibly easy to extract your cycling power numbers. Being frustrated with the typical cost of buying a separate power meter for training purposes, it was obvious that this was something we NEEDED to include as an option for our trainer. ANT+ and BLE? Yes please! The power meter is actually so simple and efficient that a pair of AA batteries can power it for hundreds of hours, and it’s incredibly accurate, tracking extremely well with every power meter used for validation. You don’t even need an off switch (but we’ll give you one anyway, no charge!), and it can be completely wireless to boot.
A body in motion...
A few hundred years ago, there was a really smart guy, Newton, that was conked on the head by an apple (or so the story goes). As a result, he invented physics (well, explained some of it anyway). One of this guy’s laws, said that a “a body in motion, stays in motion”. Basically, the heavier something is, the harder it is to change in speed. Or, looking at it another way, something really light can change speed very rapidly. So, aside from the history/physics lesson, why would we bring this up? It turns out that the major limitation of any trainer is how light modern bike wheels have become. Because there is so little mass rotating, a flywheel needs to be added to help simulate the “proper” road feel. In most fluid or magnetic trainers, a large flywheel is attached to the resistance unit. We’ve accomplished the same effect by adding two relatively small weights to the wheel. The weights are secured in between the spokes, held in place by the wheel’s own speed. The faster you pedal, the more secure the weights are held in. If you have a carbon fairing on your wheel, we thought of that too. An optional weight unit fastens onto the hub, preventing any contact with the fairing and eliminating the chances of cracking a carbon fairing.
Fold or Pass?
Not being constrained with a bulky resistance unit, we asked ourselves, how low can you go? The unit is fully collapsible, and can slide under a couch or into the back of a closet without any difficulty. The folded height of the production unit is less than 3”. Compare this to a large diameter flywheel that sits on top of the folded frame, and it’s a no-brainer that the STAC Zero is perfect for anyone with a small apartment or limited storage space. This even means that you can easily take the trainer with you for a pre-race warmup, on your race tires! Cool!
How will my contribution help?
One of the biggest hurdles with any manufacturing process is overcoming the initial tooling and order size requirements that are needed to drop pricing to reasonable levels. We’ll be using your pledges and orders to help bring down costs, making it easier to get the final product in your hands. This helps to improve quality, reduce design compromises and ultimately deliver a finished product to you faster.
At STAC, we live by the words: SUFFER IN SILENCE
Risks and challenges
As much as we’d like to think that everything is all sunshine and rainbows, there’s a pesky little thing called reality that sometimes rears its ugly head. In an effort to provide full disclosure to the Kickstarter community, we’re going over all of the risks and challenges with our product, so that you can make an INFORMED and EDUCATED decision about our design and whether or not you think supporting us is the right thing.
We HAVE non-power sensing prototypes ready to go. The design is proven and manufacturable; no vaporware here. The biggest hurdle for us is having enough orders to drive costs down to a reasonable amount. Reaching our Kickstarter goals puts us over that threshold, meaning you will have YOUR trainer in a matter of months.
The most recent prototype design uses a large, expensive, but dev-friendly development board for power sensing and ANT+/BLE reporting. A production-ready system would need to use the same chip (a Nordic Semiconductor NRF51422) but with packaging oriented towards low-cost mass production. A portion of Kickstarter proceeds will go towards optimizing the electronics design to provide an easy to use and trouble free power training experience.
Tooling and manufacturing:
Early prototypes have been successfully made, but the inclusion of vanity covers and other aesthetic plastic pieces has not yet been fully explored. Until we reach a sufficiently high sales volume, the cost of the tooling for injection molding these pieces would unnecessarily drive up the price of the unit, without any real benefit to the consumer.
This is equally appropriate in the FAQ section, but it warrants discussion. As the trainer relies on generation of eddy currents in the wheel, the wheel must be electrically conductive. Unfortunately, the construction of some carbon wheels make it impossible to generate enough force this way. If you have a full carbon wheel (no alloy braking surface), the trainer will unfortunately not work on your wheel. If you have aluminum wheels, carbon wheels with an alloy braking surface, or aluminum wheels with a carbon fairing, not to worry, it is fully compatible with your wheel!
- (30 days)