Via DCR: http://www.dcrainmaker.com/...ac-zero-trainer.html
Interestingly, it doesn’t actually interface with your tire so the only noise will be from your drivetrain. Instead, it uses powerful rare earth magnets to induce resistance in aluminum rims. There’s a $350ish version that will broadcast power over Ant+ and BLE. The wheel weights are a little sketch but I wouldn’t mind having them on my 32 spoke training wheels. The wheel weights aren’t actually “needed” so this can also be a warmup trainer for TTs so long as you use something like HED Jets.
I may have to get in on the Kickstarter, because, magnets. I’m really liking the silence of this and if the magnets do their job, it will work great with my crank based power meter.
I like the concept, but having a flywheel attach to the spokes is scary. If that would come loose and fly off, it could be a deadly projectile. If you want to see what a flywheel does when it enters the human body, you can find a thread on the computrainer flywheel recall.
Hi, I’m STAC’s web/internal developer and long-time tester.
First, I’ll say the weights are optional. If your wheel is heavy (or it is light and you pedal in nice circles), the inertia/feel of the trainer isn’t an issue. My 32-spoke powertap with a wheelcover on it feels great sans weights, and even feels pretty decent without the wheelcover.
For the CT comparison, keep in mind that the tangential velocity of many flywheels (KKRM, CT, kickr) is stepped up greatly from the tangential velocity of your tire thanks to the differing roller/flywheel diameters. So if you’re pedaling at 40km/h, the outer surface of a flywheel on a typical trainer is going much faster than the weights on the zero, which will only be going as fast as your wheel. It’d still hurt if one somehow escaped your spokes at full speed, but would hurt much less than a same-wheel-speed flywheel explosion.
Structurally, the weights haven’t been (in our experience) an issue. Since they sit on the wheel fairing (rather than hang off the spoke like you might think) when in use and a bike wheel is a tension structure, they’re supported in the same way that the rest of the wheel is when you go over a pothole or train tracks. So you’re not going to have a structural failure of your wheel because of them. The thumbscrew to attach to the spoke is solely to retain the upper one once you stop pedaling.
We do have an alternative design ready, in case a lot of people are turned off by the current rev of the weights. It’s more of a pain to install (a lengthwise steel unit that hangs onto your hub and has two weights rigidly supported), but doesn’t put any real net force on the wheel or hub. Given feedback so far today, we may offer that as an option instead of the weights that DCR reviewed.
I’ve been lucky enough to use the STAC Zero for about 2 weeks now. So far I haven’t had any issues with the weights been loose. The weights I have been using are a bit of a newer design than the ones DC Rainmaker was using and they have a coating that I think will keep them in place better and protect the spokes.
When is the electromagnetic version coming with the Zwift-compatible adjustable tension?
We have our ideas, some of which probably wouldn’t even need house current to pull off. But definitely not this fall, we’re laser focused on this 1.0 release.
When is the electromagnetic version coming with the Zwift-compatible adjustable tension?
We have our ideas, some of which probably wouldn’t even need house current to pull off. But definitely not this fall, we’re laser focused on this 1.0 release.
Is this something that would be able to retrofit to verdion 1.0?
For the implementation we’re thinking of for variable-resistance, we’d probably have the option of shipping out a new magnet array and controller. Of course that’s cheaper for us and for the customer than constructing and shipping out a whole new trainer!
We are planning on offering an upgrade package from non-PM to PM (add computer, install strain gauge and speed sensor), so offering an upgrade package to variable-resistance will probably occur once the variable-resistance unit is designed (which would be fall 2017 or later. Earlier if we manage to make this a fulltime affair).
