Topeak SmartGauge D2 Digital Tire Pressure Gauge – Presta/Schrader Compatible, 250 Psi/17 Bar, Precision Air Pressure Reader with LCD Display for Bikes, Motorcycles & Sports Equipment

Why it's worth it

A pocket-sized digital gauge that reads both Presta and Schrader valves with a twist of the head, up to 250 psi. It has a bleed button so you can dial pressure down precisely instead of guessing.

Tire pressure is the most neglected thing on most e-bikes and one of the few free levers you have on range. Underinflated tires roll worse, which means the motor works harder, which means you get fewer miles per charge. They also pinch-flat more easily, and an e-bike puts far more weight on its tires than the bike you rode in college.

Floor pump gauges lie, and this one doesn't. Built-in pump dials are usually approximate at best and drift as they age. A dedicated digital gauge reads to a tenth of a psi and holds the reading on screen, so you're not crouched on the garage floor squinting at a needle. Owners who've replaced decade-old analog gauges with this one consistently call out the accuracy and the ease of reading it.

From our review of 5 e-bike accessories and upgrades, by Ben Carter, Tech Editor

What we like

• +Tire pressure is the most neglected thing on most e-bikes and one of the few free levers you have on range
• +Floor pump gauges lie, and this one doesn't
• +The rotating SmartHead is the practical detail that makes you actually use it

What to know

• –It's a gauge and nothing else
• –The CR2032 battery isn't rechargeable, and a few owners have had trouble getting the battery door open the first time — usually…
• –Every external gauge bleeds a tiny amount of air just to take a reading, which matters most on high-pressure road tires