A figure eight on a bicycle wheel manifests itself in the form of a lateral runout of the rim, which, when rotated, deviates from the central plane and touches the brake pads or frame stays. This mechanical violation of the geometry occurs due to uneven tension of the spokes or deformation of the rims after hitting a curb, falling into a hole or prolonged storage under load. Ignoring the problem leads to accelerated wear of the brake system, destruction of the spoke attachment points and loss of roll, so eliminating the deformation requires immediate intervention.
For quality editing you will need spoke wrench, matching the size of the nuts on your wheel, and a stationary machine or the bike itself, turned upside down to secure the axle. The process of restoring the shape consists of sequentially loosening and tightening the spokes from different sides (bushings), which allows you to shift the damaged section of the rim back into an ideal round plane. The accuracy of the adjustment is measured in millimeters, and the success of the operation depends on an understanding of the principle of operation of the wheelset and the patience of the master.
Diagnostics and determination of the type of deformation
Before starting any work, it is necessary to accurately determine the nature and location of the damage, since the methods for eliminating the “eight” and “egg” (radial runout) are fundamentally different. Visual inspection is often insufficient, so use a marker or chalk attached to the frame or fork to mark the highest point of runout as the wheel rotates. If the rim only touches the mark on one side in a certain area, you are dealing with lateral runout, which is called a figure eight.
The cause of deformation most often is a weakening of the tension of a group of spokes, which allows the rim to move under the influence of an external force or residual stress in the metal. It is important to check not only the runout area, but also the opposite side of the wheel, as overtightened spokes can create the illusion of a flat area, hiding the real problem. For an accurate diagnosis, use runout indicator or a homemade wire device attached to a stationary part of the bicycle.
If, while rotating, you notice that the gap between the rim and the brake pads periodically disappears, this is a sure sign that adjustment is necessary. In modern disc brakes, the figure eight may not interfere with braking, but it creates dangerous vibration that is transmitted to the handlebars and frame. Thorough troubleshooting allows you to draw up a work plan and avoid unnecessary manipulations with healthy areas of the wheel.
⚠️ Warning: Before you start straightening, be sure to loosen the brakes or remove the wheel if you plan to use the machine. Trying to spin a severely misaligned wheel with the brakes applied can damage the caliper or cables.
Necessary tools and workplace preparation
High-quality editing is impossible without specialized tools, the main one of which is a spoke wrench. The size of the wrench should ideally match the splines of the spoke nuts (usually 3.23 mm, 3.30 mm or 3.45 mm) to avoid stripping the edges and damaging the nickel plating. The use of pliers or universal wrenches is strictly not recommended, as they deform the nuts, making subsequent adjustment impossible.
To fix the wheel, it is best to use a special straightening machine, which allows you to rotate the axle and accurately position the feeler gauges. If there is no machine, you can turn the bike over and support it on the seat and handlebars, attaching a plastic tie or spoke to the fork leg or rear seats as a pointer. Such improvised stand requires more concentration, but gives comparable results with proper skill.
Additionally, you may need lubricant for the spoke threads if the wheel is old and soured, as well as a felt-tip pen for marking runout zones. In difficult cases, when the rim has multiple deformations, it will not be superfluous to have a second set of spokes on hand to replace those that burst during the straightening process. The preparation of the workplace should provide good lighting and free access to the wheel from all sides.
☑️ Checklist for preparing for editing
Technique for correcting lateral runout (figure eight)
The basic principle of eliminating the figure eight is to tighten the spokes on one side and loosen the spokes on the opposite side in the deformation zone. If the rim is pulled to the left, it is necessary to tighten the spokes going to the right flange of the hub and loosen the left ones. The number of turns of the key depends on the amount of runout: for small deviations 1/4 or 1/2 turn is sufficient, for serious deformations a full turn may be required.
Work sequentially, starting from the center of the figure eight and moving towards the edges of the warp. For example, if the maximum runout is at point A, start there, making a correction, then move to adjacent spokes, reducing the amount of impact. After each series of twists, be sure to spin the wheel and check the result against the pointer.
Alternating tightening and loosening helps to avoid the appearance of new distortions. If you simply re-tighten the left spokes to remove the left figure eight, the wheel may become oval or develop radial runout. Therefore, balance is key: if you tighten one side, be sure to loosen the other by a similar amount, maintaining the overall vertical tension of the wheel.
Elimination of radial runout (egg)
Radial runout, or “egg,” occurs when the distance from the wheel axle to the rim changes as it rotates: at some points the rim comes too close to the axle, at others it moves away. To eliminate this problem, it is necessary to work with the tension of all the spokes in the problem area at the same time, without separating them on the sides. If the rim is too close to the axle (concave), you need to evenly loosen all the spokes in that sector.
In the case where part of the rim sticks out (the hump), it is necessary to tighten all the spokes in this area, pulling the rim closer to the hub. This operation is more risky than straightening the figure eight, as it requires precise calculation so as not to overtighten the spokes to their breaking point. Often, to eliminate a strong “egg”, it is necessary to first loosen all the spokes of the wheel, correct the shape and then make a final guy to working condition.
The challenge is that eliminating radial runout often affects the lateral geometry. After correcting the “egg”, it is almost guaranteed that the figure eight will need to be corrected again. This process is iterative: you remove one problem, check another, and so on until the ideal result is achieved. Using lubricant on the spoke threads is critical here to ensure the nuts turn smoothly and not jerkily.
⚠️ Caution: Do not try to correct severe radial runout by just tensioning the spokes if the rim has a physical dent or crease. Metal has an elastic limit, and excessive tension will cause spokes to break or the rim to collapse.
Final adjustment and tension check
After the visual runout has been eliminated, it is necessary to check the evenness of the spoke tension. Even a perfectly round wheel with different spoke tensions will quickly lose its geometry during operation. To check, use pliers to measure the tension or simply tap the spokes with a screwdriver: the sound should be the same and ringing throughout the circle, differences in tone will indicate weak or overtightened areas.
Final finishing includes “setting” the wheel. To do this, take the wheel in your hands (or use a bicycle), press firmly on the rim in several places on the sides, simulating the load from the rider’s weight. After such a procedure, the tension of the spokes usually weakens, and the figure eights may appear again. Repeat the straightening procedure to compensate for metal shrinkage and achieve stable values.
The final stage is to install the wheel on the bike, check the alignment relative to the brake pads and test ride. If there are no knocks or beats when braking or driving over bumps, and the wheel rotates freely, the work can be considered complete. Regular checking of spoke tension after the first 50-100 km of a new or repaired wheel is mandatory.
Secrets of the pros
How to edit complex eights: For complex cases, when simple editing does not help, experienced mechanics use the “brute force” method. The wheel is completely un-spoked, the rim is straightened in a vice (if possible) or changed, and reassembled with zero tension. There is also a method of local heating of the rim (only for steel!) to relieve internal stresses, but for aluminum and carbon rims it is strictly prohibited, as it will lead to a loss of strength of the material.
Typical errors and fault table
Beginners often make mistakes that ruin all their efforts or worsen the condition of the wheel. The most common of these is an attempt to remove the big eight in one pass, making full turns of the key. This leads to constriction and the appearance of new deformations. Another mistake is ignoring the condition of the spokes themselves; If a spoke is bent or cracked, no amount of adjustment will make the wheel stable.
The table below shows the main symptoms and how to resolve them, which will help you quickly diagnose the problem:
| Symptom | Probable Cause | Elimination method | Difficulty |
|---|---|---|---|
| Lateral runout (figure of eight) | Loosening a group of spokes | Contract tension (pull one side, loosen the other) | Average |
| Radial runout (egg) | Rim impact, different tension | Uniform tension/loosening of all spokes in the sector | High |
| Constant creaking | Friction of spokes at intersections | A drop of oil at the intersection of the spokes | Low |
| Spoke thread breakage | Corrosion, constriction, bad key | Replacing the needle and ligating the area | High |
Avoid using low-quality instruments, which lick the edges of the nuts. Repairing a broken spoke nut is a labor-intensive process that requires drilling out or replacing the entire spoke, which is impossible in road conditions. If you feel that the nut is too tight, do not force it, but use a penetrating lubricant.
⚠️ Attention: Aluminum rims have a limited edit life. If the wheel has been straightened more than 3-4 times or has deep cracks at the spoke holes, it is safer to replace the rim or the entire wheel rather than risk destruction at speed.
Helpful advice: To prevent the spokes from turning along with the nut when you truing old wheels, lightly press with your finger where the spokes intersect at the rim. This will create additional friction and will only allow you to turn the nut.
Frequently asked questions (FAQ)
Is it possible to remove the figure eight without a spoke key?
Theoretically, you can use pliers or an adjustable wrench, but the risk of damaging the edges of the spoke nuts is 90%. A stripped nut will turn a simple repair into a complex spoke replacement. If there is no key, it is better to drive to a store or workshop, carefully tightening the nuts with the available tool with minimal force.
How often should spoke tension be checked?
New wheels require checking after the first 50-100 km, as the spokes shrink. Further, it is recommended to carry out a preventive inspection once a season or after serious stress, such as descending from mountains or driving on broken roads.
What to do if a knitting needle constantly breaks in one place?
This indicates local overstressing of the rim or defective spoke itself. It is necessary not only to replace the spoke, but also to redistribute the tension in this sector, possibly by loosening the adjacent spokes. If the problem persists, you should consider replacing the rim.
Does figure eight affect the speed of a bicycle?
Yes, a strong eight creates additional air resistance and friction in the brakes (if they are rim), which reduces roll-up and speed. In addition, vibration from wheel beating takes away the cyclist's energy and reduces riding comfort.
Key Takeaway: Wheel truing is a tension balancing process. There is no one “magic” knitting needle that needs to be twisted. Success depends on consistent, small changes in spoke group tension and constant checking of geometry.