The advent of tubeless tires has allowed us to run tire pressures I was unable to contemplate, let alone willingly try, 20 years ago. If I was on one of my road bikes, I could guarantee you that both tires were pumped to 7 bar—105 psi—at minimum. On my ‘cross bike I was running at least 60 psi, possibly more, if the course was smooth and fast.
The gauge on my Silca pump, if I’m honest, was not especially accurate. If I tapped the base on the ground while the pump was pressurized, the needle often moved. I figured it didn’t really matter what the pressure was, as long as it was above 100 psi. Even if the gauge was off by 10 percent, the pressure was still high enough to give me the performance I was looking for. At least, that’s what I reasoned back then.
But as air pressure in our tires has dropped, an error of 10 percent—possibly more—can mean the difference between rolling over something and dinging a rim. With 20 psi in my rear tire on my mountain bike, I don’t bottom out the tire, but at just 2 psi lower (a 10 percent error)—18 psi—I have.
Which brings me to the Topeak Smartgauge D2X. I’ve become rather addicted to this thing. It measures pressure in imperial (psi), metric (kg/cm2) or bar, and it switches between the three with the press of a button. A slider on the head will switch between presta and Schrader valves—no unscrewing the head and flipping an easily dropped piece of plastic upside down. My level of delight at not facing this annoyance surprised me.
My favorite feature of the Smartgauge D2X is the ginormous, three-digit LED readout. Too many product managers have eyes that need no correction and I find myself needing reading glasses for entirely too many bike products I’m supposed to use on the bike—where, unless I’m looking at something on my bike, I need no vision correction. The LED readout is also lit so you can discern it even in bright sunlight. Better still: The gauge rotates so that even if the valve sits at an odd angle, you can rotate the gauge to a position that is readable. Kudos.
With a suggested retail price of $57.95, some folks will balk at spending on a gauge what you can purchase a whole pump for. I worried that I might not reform my ways and continue to use my pumps without checking pressure with the Smartgauge D2X. It turns out, I use it slavishly.
The first few times I used the gauge I tried pumping my tires up to my preferred pressure and found on occasion that I came up short and had to add a few more strokes of the pump before re-checking the pressure. The solution is an easy one: Pump to a pressure higher than you will ride and use the button on the pump head to release pressure until it drops to your preferred mark.
The Topeak Smartgauge D2X takes a CR-2032 battery, which can be found at any grocery or drug store. There are enough devices in my life that use them, I buy the batteries in six packs now. Battery life seems good, but probably not heart-rate-monitor–chest–strap good.
Final thought: I wish it came with a keyring attachment or a holster.