The car Bibles product reviews: Michelin Digital Tyre Pressure Gauge.
Product Reviews
Michelin Digital Tyre Pressure Gauge
Tested July 2006 
This is part of Michelin's new line of automotive products which came out in 2006. Given that they've been in the business of selling tyres for ages, it seems like the question surrounding their new product line is "What took you so long?". This review goes hand-in-hand with the new digital tyre inflator below. At the time of writing, this new pressure gauge cost $19.99 from motoring parts stores. It comes in a vacuum-wrap plastic display box with a small window in it for people to 'check out' the display by pushing the button. My first piece of advice - get one from the back of the rack. The front one will likely have been hammered by ham-fisted patrons for weeks if not months before you get to it. The gauge itself is nicely built and quite weighty. It's made of what feels like billet aluminium with rubber inserts for grip. The inserts are a particularly sticky compound so if you put it down on the garage floor, it will come up covered in muck. It comes with an expanding neoprene pouch that contains the instructions, and an adapter for certain types of bicycle valve. The adapter is a small brass unit which has no place to store it in the pouch other than loose, and when you do, it can scratch the silver finish on the pressure gauge. The instructions are pretty simple and once you've used the unit once, you'll likely not need them again. It comes with three batteries pre-installed and has an error of +/- 1psi up to 50psi.
It's really easy to use. Click the button and the LCD display lights up blue with black digits, and the collar around the nozzle lights up a similar blue - a nice feature if you're in a dark corner. Click the button to cycle through three pressure units - PSI, Bar and kPa. Slot the nozzle on to your tyre valve for a couple of seconds, pull it off and take a reading. Simple. The nozzle itself has a snug collar in it so it's easy to locate on the valve stem, and helps prevent you from accidentally letting air out of your tyres whilst taking a measurement. After 90 seconds of inactivity, the unit shuts off. Apart from the lack of place to put the brass adapter and the super sticky rubber inserts, it's a nice gauge to use. I removed half a star from my rating for the lack of storage for the brass adapter and the over-sticky rubber inserts, and another half because it's nearly impossible to use this gauge on motorbike tyres due to its design. The shape of the handle is great for testing car tyres but the angle it needs to attach to the valve stem means it interferes with spokes or brake discs on motorbikes.
I tested it against the digital inflator, as well as an old stick-type pressure gauge and a quality analogue gauge which I have calibrated every 6 months. At 40psi, the stick gauge reads 39psi and Michelin's digital pressure gauge reads 40.5psi so its well within tolerance, and it matches the inflator tested below.