Topeak SmartGauge D2 pressure gauge review

Tyre pressure is a significant determinant of a road bike's performance. Too high and you will get a stiff ride and there's the risk of skidding or even a tyre exploding on long downhills. Too low and the bike will handle sloppily and you may get tyre roll or risk pinch flats. So it's useful to be able to measure your tyre pressures accurately. It's also important off road, where grip on loose surfaces can be critical and you don't want to bottom out on a wheel rim.

The Topeak SmartGauge D2 pressure gauge digitally measures pressures up to 250psi in 1psi increments, allowing you to accurately measure and tune pressures in tyres with Presta or Schrader valves, or in shocks for the off-road minded. It’s easy to use: just switch on, push onto the valve and wait until it beeps, with the reading being displayed even once the gauge is taken off the tyre.

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The screen rotates around the valve head so that you can choose a good viewing angle, and there’s a button on the side to bleed the valve and fine-tune the pressure. Power is supplied by one CR2032 button cell and there’s an auto-off function after 30 seconds of non-use.

The gauge can be set to measure in psi, bars and kg/cm², with a single button toggling through the options. The selection of valve type is via a slider on the head, which locks the central part of the connector when Schrader valves are being used.

It's easy to fit the gauge over a Presta valve head, with little chance of disturbing the valve core and releasing air from the tube accidentally. Each measurement does result in a loss of 2 to 3 psi from a tube though, so repeated measurement will result in a significant loss of pressure which will potentially need to be topped up.