How to adjust bike rims

When we travel through the jungle and jump off high platforms, again and again, excessive impact will cause overload damage to our wheels. To allow our wheels to roll smoothly and safely, it is very important to adjust the rims regularly. In this article, let’s have a deeper understanding of bikes and discuss the adjustment of rims.

Bike wheel

1. When do you need to adjust the rim?

Minor deformation problems can be solved by rim adjustment, such as the center of the rim and the wheel axle are not coplanar, or the wheel axle and the rim are not perpendicular to each other. If the deformation is visible and too large, you should replace the rim directly. It should be noted that rim adjustment is one of the most difficult processes in bike installation and adjustment. It requires the use of professional tools and a certain amount of patience. If your rims are expensive and you are not good at maintenance, you’d better not adjust the rim without professional instruction, otherwise the rim may be damaged. 

2. The principle of rim adjustment

There are four important elements when adjusting rims, Circular runout, End offset, Symmetry and Spoke tension.
The longitudinal movement of the rim does not affect the end offset. 

The adjacent spoke nuts connecting the left and right hubs should be tightened or loosened by the same number of turns at the same time. 

The lateral movement does not affect the roundness. The number of tightening turns on adjacent spokes is the same as the number of loosening turns. For example, one turn tightening on the left spoke, one turn loosening on the adjacent right spoke, or two adjacent spokes on the right loosening together for one turn. 

Note that you should adjust roundness first and then adjust the offset.

Adjusting the spoke

3. Adjustment steps

First, there are some tools we will use: wheel truing stand, spoke wrench, screwdriver, tension meter etc.
Use a screwdriver to tighten the outside rim spoke nuts clockwise; use a spoke wrench to tighten the inside rim spoke nuts counterclockwise.

Spoke wrench
Tensiometer

(1) Thread all spoke nuts until nuts just cover the spoke threads. 

(2) Starting from the valve, screw all nuts into the same number of turns until the rim becomes hard and the spokes cannot be easily shaken by hand (you can screw in 2 or 3 turns at a time).

(3) Fix the rim on the wheel truing stand and use the tensiometer to check whether the tension of all spokes is close (10% upper and lower limits), if you do not have a tensiometer, you can pinch the adjacent spokes on the same side with your fingers for a rough estimate. If there is a big difference in the tension of some spokes, adjust them to close to other spoke tensions.
(4) Adjust circular runout 

Generally, the circular runout is reduced by tightening the spokes. During the continuous adjustment process, the rim will gradually be tightened. 

Use the wheel truing stand to find the highest bulge area of the rim. If the bulge is between two spokes, adjust the same number of turns on each spoke until the bulge almost disappears. If the bulging center is at a certain spoke, tighten this spoke one turn, and then adjust the adjacent two spokes which connect the rim on the other side by 1/2 turn each until the bulge disappears. 

Adjust the number of turns to be evenly distributed so that the spoke tension changes to the left and right hubs are equal. According to the above method, adjust until the longitudinal runout does not exceed 1mm.

The wheel rim jumps when rotating

Note: the adjustment actions should be as independent as possible and not affect each other. During the adjustment process, try to find a position with a larger deviation and gradually reduce the circular runout. Do not expect to adjust the spokes to the most accurate roundness only at once. 

(5) Adjust end offset

Face the wheel truing stand, turn the rim, and find the farthest position of the rim from the center line. If the rim is offset to the left, loosen the spokes connected to the left hub, and then tighten the spokes connected to the right side. 

For example, if the rim deviates to the left, and the farthest deviation is between two spokes. Loosen the left spoke 1/2 turn and tight the right spoke 1/2 turn. If the farthest deviated position is close to a certain spoke on the left, loosen the spoke 1/2, then tighten the two spokes connected to the right hub 1/4 turn each.

The adjustment of the right side is the same. There is no need to adjust each deviation to the best, but should be adjusted alternately until the rim end face does not deviate left or right.

Bounce appears on the end face
rim offset

(6) Adjust the rim center line

With the help of the center mark of the stand, if the rim deviates to the left side of the center line, loosen all the spokes on the left side starting from the valve by 1/2 turn (the number of turns is for reference only, adjust according to the actual status), and tighten all the spokes on the right side by 1/2 turn to make the rim move to the right until it is centered.

(7) Spoke torsion release

While tightening the spoke nut, the twisting of the spoke generates enough reaction force to offset the friction, and the nut begins to move, but the spoke will remain twisted. Spoke twisting force can be released by the “over and back ” action of the spoke wrench. For example: If you want to tighten a spoke exactly 1/4 turn, you should note the position when turning 1/4 turn, then turn it a little more, and then return to that position.

(8) Check and micro-adjusting

Recheck the rim circular runout and end offset and make final fine adjustments.

Don’t hesitate to leave a message if you have anything to share. We are looking forward to your idea and story.

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References:

[1] ‘Cycling Bible’ Editorial Board. Cycling Bible [M]. 1st Edition. Beijing: Machinery Industry Press, 2013.

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