By 
Price: $199
Weight: 10 grams (per wheel)
Use: road, trail, mountain, gravel, cyclocross
Battery Life: 300 hours (claimed)
Chances are if you bought a new car or truck in the last ten years it has real-time tire pressure monitoring via valve stems that transmit data to your dashboard. Quarq, the electronics division of SRAM that brought us super-reliable power meters and data collection units like the Qollector and ShockWiz, now offers cyclists the same real-time feedback so you can set your ideal tire pressure on your bicycle.
Packaged in sets of two, these 10-gram units work on any valve stems—tubeless or inner tube—with removable cores.
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.
RELATED:
5 Things You Should Know About Tire Pressure
Quarq claims the tool is accurate +/- 2 percent with a 0.1psi resolution, and says the small gadgets won't clog up with tire sealant. Our initial test has been good, but we'll keep testing them—clogged valves are a normal part of sealant use. The units carry a IP67 dust and waterproof rating; enough to survive stream crossings and pressure washing on mountain and cyclocross bikes. They are powered by an easily replaceable CR1632 battery that has a claimed 300-hour life according to Quarq.
Test Impressions
The TyreWiz units are a snap to install. Simply unthread the core from your valve stem (I used it on a set of tubeless road wheels) and thread on the TireWiz in its place, positioning it inline with the spokes.
The TyreWiz app was also easy to use. You set your weight and also how much extra kit you have on that day, for example: to account for wearing a mountain bike hydration pack one day and riding without one another time. You also need to input which wheel (or both) you're mounting the units to, all of which you can do in the settings screen.
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.
Seeing real-time feedback on tire pressure was interesting. While my pressure didn’t change over the course of a day's ride, having the TireWiz installed let me see that I lost about 15psi overnight and warned me to top up before hitting the road on subsequent days.
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.
The jury is still out on whether this is the next big thing. It doesn't yet have any logic to recommend pressure based on your riding style, but it does provide valuable feed back to help you find and maintain ideal tire pressure. It's not cheap, but it's easy to use and given how important tire pressure is, could be a nice boost for some riders.
The Wiz will cost $199 for a set of two and be available in June. You can pre-order now from Quarq.
