STAC Zero Powermeter Bike Trainer

I live in a condo with my wife and young kids and neighbors above and below me so I was a bit wary about the noise from an indoor trainer. I'd tried the CycleOps Hammer and Fluid2 trainers and they were way too loud. Fortunately the STAC Zero really is totally silent with the only sound coming from the drivetrain of my bike. My wife doesn't even need to turn up the volume on the TV when I'm using the trainer in the same room!Initial setup of the trainer was pretty straightforward. There are tons of really helpful articles and videos on the STAC Zero website that walk you through the whole setup process. The alloy wheels on my Trek Domane weren't compatible with the STAC Zero magnets so I bought a cheap aluminum Mavic Aksium wheel and foldable tire for under $150 which works well since I can just leave the included wheel weights attached the wheel when I'm not using the trainer. Figuring out the right spacing for the magnets took a little bit of experimentation. You don't get enough resistance if the magnets are too far apart and you feel like you're riding in sand if the magnets are too close together. Fortunately the trainer includes a magnet spacer that allows you to quickly dial into a setup with good road feel and plenty of resistance. I've gotten to the point where I can get the trainer setup in about a minute. The trainer also folds up for easy storage under my bed when it's not in use.I highly recommend the STAC Zero to anyone looking for an indoor trainer!

Gives power readings to access my effort during a workout. This trainer is nice an quiet so watching a video is enjoyable during my session

I really wanted to like this trainer. The no-touch magnet idea is quite clever and VERY quiet, but it fails at it's primary purpose (as a trainer). It's like pedalling with light braking. I had to spin the weighted wheel @ 30~35mph (yeah, miles per hour, not kph) to get a tolerable road feel. Typical speeds give a slog / whoosh / slog feel. So, I can't in good conscious give it any more than one-star.It also fails it's portability goal, which isn't about weight. It's about time and effort to setup and tear-down. It's going in a car trunk, so weight isn't a big deal. Setup & tear-down, however, is huge and it requires near spoke-breaking effort combined with hours of resistance fiddling. I'd rather change a flat tire than setup or tear-down this trainer.Basically, it feels like a very polished DIY that needs about another 10 iterations of mechanical engineering. They can get there eventually -- the underlying concept works -- it's just a LONG way from being usable. Best advice: sell the IP to an experienced trainer producer or steal one of their oldest and most experienced MEs. Test it with people that hate trainers and/or have no mechanical aptitude. Give them absolutely zero help -- the box of parts and the directions have to be enough. Redesign. Test. Repeat another 10 cycles.-- details below on each little flaw (for the curious) --Flaw: all-or-nothing resistance adjustment. It feels like brakes, but unlike your brakes, you can't make it a "a little more or less" than it is now. You have to release it and completely reset it from scratch. Fix: redesign the adjustment to be screw or ratchet-based. Appropriate set-screws would do it. It doesn't need to be a complex motorized gadget that adjusts while you ride, but it's essential to support minute changes in resistance to the current setting.Flaw: magnet arm has an extreme wobble (3~4mm). Fix: much MUCH better QA, use screws, or use two arms per tray. There should be ZERO wobble in the arm -- makes it impossible to adjust resistance. Neither spacer nor measurements help when the wobble undoes your work.Flaw: power meter must be removed to swing the magnet arm into place (for use or for transport) and then reinstalled. The plug that holds the arm in place can't be removed or reinserted due to power meter location. If you have to unscrew the meter every time you move the trainer, why bother with the finger-settable plug?Flaw: horrendous weight install & remove. Fix: complete redesign mandatory here -- go back to 2016 style or make the arms detachable and as thin as spokes. Make the weights thinner (by about half). I'd rather change a flat than put the 2017 weights on or off.Flaw: weights are much MUCH too light. Fix: double or triple the weight and/or increase the arm length. This is the only mechanical fix you can do for the severe slog / whoosh / slog problem with the resistance at more typical wheel speeds under 30mph.Flaw: too many parts required after first setup: spacer, weights, screwdriver, wrench, trainer. The resistance spacer is especially easy to loose. Typical parts needed for teardown and 2nd+ setup on other trainers? Just the trainer. Fix: pick ONE adjustment tool (eg. allen) and make all the parts need only that. Get rid of spacer -- fixing wobble and relative adjust issue removes need for spacer.Flaw: no adjustment "memory". There's no way to store a setting then reapply the exact same setting after transport. So, the 2 hours you spent getting just the right adjustment (or as best you can tolerate) is completely lost the first time you move the trainer. Fix: set-screws is the simplest method that comes to mind, but there are likely others.Flaw: magnet "tilt" isn't adjustable. This likely isn't too much of an issue, but if the magnet array could be tilted to match the rim, you'd likely need less magnets. That would translate into reduced cost, which you could pocket or use for more competitive pricing. My rim is pretty square, but I've see a lot of wheels with a pretty steep angle from tire to spokes.Flaw: front feet have no "shoes". I had mine setup for only a few days. Longer use would have cut all the way though my training mat and started in on the hardwood floor. BTW, this makes it less portable, too. Bare metal is a no-go in too many situations. A bare metal corner (even rounded) is worse. Fix: add "shoes" or something similar for the front feet.

I love this trainer, and I am quick to brag about it and recommend it to others whenever I have the opportunity. It’s silent and there’s no wear to my tires because the wheels aren’t touching anything (the magnets hover near the rim for resistance). I train to Sufferfest videos, and I use the built-in power meter to monitor my effort levels throughout the workouts.The trainer provides the full resistance range: there is enough resistance for me to stand and pedal at high resistance at 50 RPM, and I can also shift my gears for low resistance at 110+ RPM. I set the magnets as close as I could without touching the rim by setting the quick-release slightly under the max tightness so I could nudge the magnets a little for fine adjustment. (I only nudged them closer for the occasional low-RPM climb – any setting with the magnets generally near the rim was fine for reaching my max power at 80+ RPM in a low gear).With the weights in my back wheel, I like the pedaling feel. It also feels stable sitting and standing during workouts.Overall, I haven’t thought about the trainer since I set it up a few months ago, which is what I wanted. I do the interval training, shift gears, change cadences, and sit and stand just like I would on the road, with the bonus that I can watch my power so I can’t slack off. I think it’s a pretty neat piece of technology.

+ totally silent, the only noise is your groupset! (yes, I clean the chain more frequently now!)+ family friendly+ apartment friendly - store it behind the couch!+ 300W at 50rpm possible simulating very hard hill climbs that other trainers lock up at (some big names cannot cope with this)+ doesn't wear the tyre.+ no need to have a turbo wheel - I use my aero road wheels with this to warm down sometimes.+ easy to install weights to give a good feeling - removes the lumpiness.+ portability - goes in suitcase for travel and with bike in bike box - can warm up pre-events or even in hotel rooms.+ upgradable - it will take the next generation components - no need to buy a new trainer+ works with Zwift and more.