Ask the Editors: Free ATV Tire Flex Detector?
Dear ATVC:
Is rim scrub a viable means of determining if I’m running too much or too little air pressure in my ATV without a tire gauge?
Good question! For those who don’t know, rim scrub is, like the name suggests, what happens when the sidewall of a tire folds over onto the rim just enough to clean the rim’s surface due to the rubbing.
It’s a popular technique used by motorcycles but the key difference between their setups and ours is that most bikes run tubes (while conversely most ATVs run tubeless wheels/ tires). However the simple science at play here does indeed transfer.
In short it’s an easy means of, literally, at a glance, determining if your tires are too hard or too soft out on the trails or at the track.
While the moto business has a much clearer view of how to read the evidence left from the tire/ rim contact but do keep in mind that a spoked moto wheel contains much less surface area to read. Additionally, ATV rear wheels are often too concaved to offer much info.
However, with front wheels especially, checking to see if there’s rubber scuffs present during a ride, you’re likely running too much pressure. If instead the area where the rim meets the tire bead is sparkling clean in contrast to the rest of the wheel, you’re likely running too little.