While shooting the breeze with a veteran mechanic recently, he told us about a nightmare scenarios that he’d run into a few times, where dirt became jammed in the threads between an axle and axle nut. The resulting friction caused the threads to gall, making it impossible to remove the axle nut. As he said, “It’s really tough to cut an axle nut off, not to mention the cost of the parts. Plus, if it seizes up, while you’re installing a wheel, you can get a false torque reading. You’ll have so much friction that it won’t really be tight.” Fortunately, this wasn’t on bikes that he’d worked on, but for customers who were riding the brand bike he was supporting.
So how does it happen? “Obviously dirt collects around the axle blocks and axle slots on the swingarm…even on the wheel spacers or brake carrier.” Of course, mechanics commonly grease the axles and threads before sliding them back into place, which makes it particularly easy to pick up dirt. As you push the axle through, it’s easy for it to pick up good-sized rock on the axle threads.”
His suggestion was to make sure to keep everything as clean as possible. “Take a rag and clean the parts, or make sure to clean all the surfaces, and both sides of the swingarm. Make sure the slots are clean, and the brake carrier is clean. Even inside the wheel spacers.”
He also suggested not leaving spare wheels laying around. “The inside of the hub where the axle goes has a lot of oil and grease in there, and if the wind has been blowing, the dirt can blow through there and stick, which could cause you problems. With the wheels, you can take a rag and use a long screwdriver to push it through and collect any dirt…and that’s also why I don’t leave my spare wheels outside.”