Magene S3+ Speed/Cadence Sensor for Cycling, ANT+/Bluetooth 4.0 Wireless Bicycle RPM Sensor

A bit concerned about the negative reviews, but at the price thought i’d give it a go. VERY IMPRESSED!! Works perfectly. One for cadence the other for speed. Set up on my racing cycle in the garage on a standard turbo trainer (rear tyre friction roller), Huge TV in front with HDMI link to my iPhone using the ZWIFT app. My phone picks up (Bluetooth) my heart rate monitor (Garmin) and the these two sensors, really easily, in freezing weathers too (lots of layers!!!). Accurate read out on my screen, a great way to exercise and get perfect feedback to improve your training and physique. The ZWIFT app picks up the units with a couple of hand cranked revolutions of the pedal to wake them up. Never had a problem yet... many virtual miles travelled!!

Works brilliantly. Cannot fault it at all. Unlike the couple of reviews that are negative about the device and its compatibility with certain apps, it has been known for quite some time that a lot of apps are moving away from permitting third party devices work with them or require you to have a paid subscription to be able to do so, Strava one of these. So bearing this in mind blame the app developers and check before hand. That said I have Strava premium account so no loss for me and it works a treat.Set up, once the fiddly part has been done, using the supplied fixing kit, getting the sensor fitted to the back wheel and paired with my phone is straight forward just like their heart rate monitor that I also use which I can say has been absolutely spot on so far. Can't fault this process at all for either device. Simple as one two three.In use as speed or cadence sensing, I have found the sensor to be just as good as various other premium-priced devices that I have used in the passed. No loss of connections, no bad syncs, no errors at all from my experience so far. Switching between the two modes does require the fiddly part of unclipping from the rear hub and placing replacing the battery but that is nothing, most of the time its fitted and stays put but on some days I will fit the sensor to the crank arm for use on the bike trainer and use the cadence features. No issues with speed or cadence pickup. Given the fact it's on one unit and no magnetic counterpart switching between the two is an acceptable part of such dual usage. To get working you just need to power up your app and Bluetooth and rotate the crank or wheel and the pairing will be instantaneous.Definitely a good device for those looking for a cadence or speed sensor with good reliability but on a budget.

I have been wanting to have a cadence sensor for zwift training sessions for some time, and finally pulled the trigger and used it immediately after receiving the delivery.The setup cannot be simpler, take out the battery plastic, insert the battery, check if red light is on, security the sensor on left crank with the rubber band, start zwift (or any app that connects with cadence sensor), pair, found it, done.I used to use a metronome app to check the RPM, which is really inconvenient and annoying (think beep, beep, beep, 90 times per minute for >1 hour) and would drive the kids crazy, now it's all measured from each pedal stroke.The accuracy is good, I actually took out the metronome app and set it at 90RPM and rode the same cadence, they do match. However I am sure there is a tolerance (88-92 maybe) but it's really unnoticeable and much more accurate than me following the app.Price wise, well clearly a win over Wahoo sensor.I read other reviews where people said that the sensor could get lost when riding outside, and the rubber band would break. True, these could happen, but can be easily solved as well - use nylon cable ties, wrap an adhesive tape around the sensor and crank, double sided adhesive tape to add extra security (if the inside of your crank is not recessed), and make sure to put the sensor on the inside of the crank not outside. If you do want to remove it frequently and also ride outside with it, then it's not the fault of this product as it's not possible to have included all the rubber bands in the package that suit all size of cranks, are strong and durable enough when very tight and stretched, and easily removable at the same time. Wahoo sensor only comes with cable tie FYI and costs almost double.Definitely 5 star.

The "remove & reinsert battery to change modes" thing seems a bit hit-and-miss. Having finally got the two modules correctly configured, I installed them on my bike and went for a ride. When I got back, the speed sensor had somehow changed itself to cadence mode. It's a bit fiddly removing it, messing with batteries, and then replacing it. A similar thing happened with the cadence sensor a few days later (although that's less fiddly).Getting the sensors to connect to the app is *very* hit-and-miss - there seems to be no pattern to when it works and when it doesn't, so it's very much a case of trail and error.I've contacted the vendor about both of these issues, and rather than answering the questions I asked, they've told me to remove & reinstall the battery (which is what I've done previously) - no indication of how to fix these issues.I have no way of knowing how accurate they are - but given how wrong they get these fundamentals, I can't imagine much effort has been expended on calibrating them correctly.In short, these are not the sensors you are looking for - look somewhere else.[Addendum] To make matters worse, the lugs that hold the cover in place is made of extremely low-quality plastic. Given that the design of the devices requires removing and replacing the battery multiple times, it's not going to last very long at all. You'd be better off just throwing your money in a river.