Wheel Truing - Part Identification

Rim, spokes, nipples, hub (flanges and locknut).

Fig 1

Updated: 12/11/2006

Fig 2

Tools: spoke wrenches, truing stand, spoke tensiometer, dishing tool.

Fig 3

The correct size wrench is the smallest one that will fit on the nipple.

Updated: 12/11/2006

Fig 4

Truing stand - adjusts to fit any size wheel.

Fig 5

Spoke tensiometer - spring loaded, measures how much the spoke bends. Includes reference charts with proper tensions for various spoke sizes and types.

Fig 6

Wheel dishing tool.

Updated: 12/11/2006

How Spokes Work

Spokes suspend the rim around the hub by tension. In other words, they pull on the rim in order to keep it round

and centered over the hub. The spokes from the right side of the hub pull the rim to the right and the spokes on

the left side of the hub pull the rim to the left. As you go around the rim these spokes alternate left, right, left.

The tension of each spoke is adjusted by turning the nipples. Tightening a nipple will make the spoke pull harder

on the rim, and will move that section of the rim in the direction of the spoke and toward the hub.

There are four aspects of a properly trued wheel:

Lateral true: This is how much the wheel wobbles side to side as it spins. The most common problem with

wheels is when the go out of true laterally and rub the brake pads or even the frame.

Radial true: This is how round the wheel is. A wheel which is not radially true will wobble up and down as it

spins.

Dish: The is the measure of how centered (as a whole) the rim is over the hub. Generally, if a wheel looks

centered in the frame it's considered properly dished. A wheel which is way out of dish, though, can cause

handling problems or make brake adjustment difficult.

Spoke tension: The overall spoke tension of the wheel. A perfectly trued and dished wheel will not stay that way,

and is more easily damaged, if the overall spoke tension is too high or too low.

How to Adjust Spoke Tension

Adjustments to spoke tension are made by turning the nipples. Nipples have standard right-hand threads, i.e.

righty-tighty, lefty-loosey, however from the your vantage point while working on the wheel it will look like

lefty-tighty, righty-loosey. This is because you are working on the bottom of the nipple (imagine turning a screw

from the threaded part instead of the head).

So to tighten a spoke, turn the nipple counterclockwise.

To loosen a spoke, turn the nipple clockwise.

When a nipple is turned the spoke will twist slightly. At some point while riding it will untwist and your

wheel will go out of true. Therefore, it's a good idea, every time you make an adjustment, to overturn the nipple

slightly then back it off (about 1/8 turn).

What is Proper Spoke Tension?

Spokes will have different optimum tensions based on their thickness, material, and shape. A spoke tensiometer

measures the tension of a spoke and comes with a chart listing the proper tensions for different typs of spokes.

Another method is to go by the sound of a plucked spoke. It should ring at a fairly high pitch (some say Eb above

middle C). If it rattles, it's too loose, if it gives off a harsh ping, it's probably too tight. Basically, the spokes should

be fairly firm with some give.

On rear wheels the spokes on the drive-side have slightly higher tension than the non-drive-side spokes. That is

because the rim must be dished farther to the right relative to the hub to make room for the gears.

Updated: 12/11/2006

Wheel Truing - Pre-Adjustment Inspection

Remove the wheel from the bike and remove the tire and tube.

a) Inspect the rim for dents, bulges, flat spots, and cracks (especially around nipples), and any other damage.

Run your finger along the braking surfaces and feel for gouging. Over time the brake pads wear away the sides of

the rim and it can fail.

Fig 7

b) Inspect the spokes for rust and damage. If working on a rear wheel, pay close attention to the spokes adjacent

to the cassette or freewheel where they meet the hub as these can easily be damaged by the chain falling off into

them.

Fig 8

c) Inspect the nipples. They should be square, without any rounded off corners.

Fig 9

Wheel Truing

1 Set up

Place the wheel (with the tire removed) in the truing stand. If you don't have a truing stand, you can use

your bike by turning it upside-down and using the brake pads as reference points. A truing stand works best

though, and this discussion is going to assume you are using one.

Fig 10

Make sure the axle is fully seated in the stand and adjust the stand so it holds the wheel firmly in place.

Fig 11

Adjust the arm of the stand so that the caliper tips are lined up with the braking surface of the rim.

Keep the caliper tips away from the rim for now.

Updated: 12/11/2006

2 Even out the spoke tension

Before beginning the truing process, it's important to even out any large irregularities in the spoke tension.

Take note of any drastic changes in tension. If your rim is bent out to the right, for example, and the right-side

spokes in that area are very loose, it's likely you have a bent rim.

Fig 12

Start at the valve hole and go around the wheel squeezing pairs of spokes.

Any spokes that are overly loose or tight should be adjusted so they more closely match the tension of the majority of the spokes.

If you come across a nipple which won't turn freely, put a drop of oil at the tip where the spoke enters and let it work down into the threads.

3 True the wheel laterally

Spin the wheel and bring the caliper tips toward the rim until one scrapes lightly at the point where the wheel is

most out of true.

Fig 13

Rotate the wheel to the point where the rim touches the caliper.

You want to move this section of the rim away from the caliper.

Fig 14

Rock the rim back and forth and find the center of the deviation.

Adjustments to the lateral trueness of the wheel should be done using the spokes on both sides of the wheel in

conjunction. This helps to preserve the overall tension of the wheel and preserves the radial trueness. If only one

side is tightened or loosened, the radial trueness will be changed.Make small adjustments, about one 1/2 turn at

a time. Remember to over turn and back off about 1/8 turn to keep the spokes from twisting.

Fig 15

Say the rim is too far to the right. Find the left-side spoke nearest to the center of the deviation and tighten it by turning it counterclockwise.

Fig 16

Loosen (clockwise) the two adjacent right-side spokes by half as much.