Deformation of the wheel rim caused by broken or loose spokes usually manifests as axial runout (side-to-side wobble) or radial runout (up-and-down wobble). If the deformation is not too severe, it can be adjusted while the wheel is still on the bike. For more significant deformation, the wheel should be removed, the tire taken off, and the wheel placed on a truing stand for adjustment. To correct axial runout: First, adjust the bearing position, tighten the fixing screws, and determine the extent and range of the axial runout. Mark the area of the rim or outer tire that is wobbling. If the wobble is to the right, use a spoke wrench to slightly loosen the overly tight spokes on the right side of the wobbling section and slightly tighten the overly loose spokes on the left side. If the wobble is to the left, reverse the adjustment method.
To correct radial runout: First, address the radial (inward) runout by alternately loosening the tighter spokes on both the left and right sides of the affected section. Then, address the tangential (outward) runout by alternately tightening the looser spokes in the same section. If the rim still wobbles, in addition to adjusting the tension of the spokes in the wobbling section, you should also adjust the tension of the spokes near that section.
Adjusting the wheel rim is a delicate task. Do not turn the spoke nipples too much at a time. Generally, only allow a rotation of one-quarter to one-half turn per adjustment. The goal is to achieve a total rim runout of less than one millimeter.
During bicycle training, due to collisions or falls, the wheel rim may become severely twisted or develop a "dead bend." When adjusting spoke tension cannot correct the issue, the rim, tire, and spokes (or part of them) can be removed, and the rim can be straightened using a wooden stick or hammer (place a piece of wood between the hammer and the rim to prevent damage). If the distortion is significant, place the rim on the ground and press it flat with your feet. You can also use a crossbar to shorten the rim’s long axis or lengthen its short axis. Then, draw a circle with a diameter of 670 millimeters on the ground for inspection. If the rim largely aligns with the drawn circle, it means the oval shape has been eliminated. The corrected rim should then be reassembled with spokes and placed on a truing stand for precise adjustments.