After that, attach a pump and air up until the wheels in your app turn green. Then go ride. The app gives a projected psi range of about +/- 5 psi for a given rider weight and tire size so you can fine tune based on real feel. Of note: I found that if you have a right-angled pump head, the weight of the head and hose could unthread the unit from the valve stem when installing the pump from the drive side. If that sounds like your setup, inflate from the non-drive side where gravity will help keep the TyreWiz from coming unthreaded.

Each TireWiz threads in to the valve core and transmits real-time data on tire pressure in Ant+ or Bluetooth to an attendant smartphone app for both Android and iOS (ready in June 2018) or newer cycling computers from Garmin, with other brands likely to follow. Through the app, TyreWiz suggests tire pressure based on wheel size (700c, 27.5/650b, or 26-inch) and tire width, plus user weight when dressed for riding. Additionally, the app acts as a digital pressure gauge. As you inflate your tires, an image of a tire on your screen turns from red to green so you know exactly when to stop pumping. Airspy is slightly bulkier, and double the weight (maybe a little more, since you remove the valve core when installing Tyrewiz). On the positive, Airlspy attaches to a spoke to keep it securely in place. They call it “theft protection”, but that’s obviously a load of mumbo-jumbo.I would say 100% of their target group have: “taking out ugly reflectors from your wheels and bike”, as step one of making a new bike ready to ride and Quarq put something way uglier in their place… While the TyreWiz app suggests tyre pressures based on your weight and tyre dimensions, I didn’t find this particularly useful for mountain biking. It suggests just 14/15psi for an 85kg rider running 29×2.5in tyres — about 10psi short of what I’d recommend.

Also note that via the app you can change how you’d like tire pressure to be shown – including PSI, BAR, and Kpa. Your tires are the only thing connecting you to the road or trail, and having optimal tire pressure can have more impact on ride comfort than both frame and wheel choice combined. But finding the right tire pressure requires trial and error. TyreWiz is the first-of-its-kind tire pressure sensor for riders of mountain bikes and road bikes, taking the guesswork out of finding that optimal tire pressure. After which, you’ll go ahead and pump up the tube like you normally would. The top of the TyreWiz is identical to the valve stem that you just removed, so it’s just like normal there. Note that you don’t utilize your old valve stem in this design. Obviously, you probably want to keep it in your toolbox somewhere in case you remove the TyreWiz devices (especially if you have fancier tubes that cost a bunch).I hardly noticed the TyreWiz once installed. And riding fast descents on the road didn’t produce an unbalanced feel or the speed wobbles I expected. That may have to do with the minuscule 10-gram weight of each TyreWiz or the Zipp 303 NSW wheelset I was using. Now, behind the scenes, it’s also recording your tire pressure into the .FIT file, so that it shows up later on Garmin Connect, as well as for 3rd parties to access. The earlier beta Connect IQ apps I was using didn’t have the code to write to the .FIT file, so I can’t show you that today. I got the updated beta app about the exact same time I boarded the plane to the US on Monday. But the good news is I’ll be giving these a whirl mountain biking over the next few days at Sea Otter, so I’ll share some data there and post it here. Also note that there is an ANT+ Tire Pressure device profile in the works, making it such that this kind of data can be better standardized. Quarq claims a battery life of 300 hours’ ride time. After a month of use, I’ve not yet been able to test that, but the batteries are widely available CR1632 watch cells. We’ve not seen one in the flesh yet, let alone tried it out, so for now you’ll have to just make do with the official press release. TyreWiz press release Smartphone app displays personalized recommendations, current tire pressure, and low/high-pressure alerts.