When you’re buying an electric pump for your car tyres, you’ll quickly notice that some models have an analogue reading for pressure, while others use a digital display. If those aren’t familiar terms, analogue is a scale with a needle (like an analogue clock has hands that go around) whereas digital means you just read the numbers on an electronic display.
A lot of people claim that one is better than another, with the majority seeming to suggest that the analogue readings are more accurate. On the other hand the digital display is used in a much more ‘at a glance’ fashion, and is often backlit too – handy when you’re using it in poor light at night.
The fact of the matter is that it’s not that important really – you’re buying a tyre inflator to keep with you for when you need it – if you’ve got a very soft tyre, what’s important is that you can get air back into it to a safe pressure to drive on, and be reasonably sure it’s not coming straight out again. For that reason, whether the reading on 27.5 PSI should actually be 28 PSI isn’t so critical after all. The pumps are calibrated to reasonable accuracy regardless of whether there’s an analogue gauge or digital display reading, so unless you have a strong preference one way or another, it’s not something we’d suggest you need to worry about!