How to True a Wheel

Truing a BMX wheel means adjusting the tension of individual spokes with a spoke key until the rim spins straight. A true wheel has no side to side wobble (lateral true), no up and down hop (radial true) and sits centred in the frame or forks (dish). You make small turns of the spoke nipples, check the result, and repeat until the rim runs straight with even spoke tension.

How truing works

Each spoke pulls the rim towards the hub. On a BMX wheel, spokes alternate between the left and right hub flanges. Tightening a spoke pulls the rim towards that spoke's side of the hub and towards the centre. Loosening it lets the rim move away.

Problem	What you see	Fix
Lateral wobble	Rim moves side to side, rubs a brake pad	Tighten spokes on the opposite side, loosen on the rub side
Radial hop	Rim moves up and down as it spins	Tighten spokes at a high spot, loosen at a low spot
Dish off centre	Rim sits closer to one side of the frame	Tighten all spokes on the side you want the rim to move towards
Uneven tension	Some spokes feel slack, wheel will not stay true	Even out tension, then re-true

See spokes and rims for more on how wheels are built.

Tools

• Spoke key. It must fit your nipples snugly. A loose fitting key rounds the nipple flats. BMX wheels commonly use 14 gauge (2.0 mm) spokes, but nipple sizes vary, so check before buying.
• Truing stand (optional). Holds the wheel and gives you adjustable pointers on each side.
• Zip tie or pointer. For truing in the frame without a stand.
• Spoke tension meter (optional). Measures spoke tension for an even, accurate build.
• Marker or tape. For marking the valve hole or problem spots.
• Light oil. A drop on stiff nipples helps them turn without twisting the spoke.

Setting up

With a truing stand

1. Remove the wheel from the bike.
2. Take the tyre off if the rim is badly out, or leave it on for small adjustments.
3. Fit the wheel in the stand and set the pointers close to the rim sidewalls.

In the frame (zip tie method)

1. Flip the bike upside down or put it in a work stand.
2. Make sure the axle is tight and centred in the dropouts.
3. Fit a zip tie around a fork leg or chain stay, with the tail pointing at the rim sidewall.
4. Trim the tail so it just brushes the rim at its closest point.

If you run brakes, the rear brake pads can work as a guide too.

Which way to turn

Spoke nipples use a standard right hand thread when viewed from the tyre side of the rim. Looking down at a nipple at the top of the wheel, clockwise tightens and anticlockwise loosens. When you work from the hub side, or on a nipple at the bottom of the wheel, the direction feels reversed.

If you are not sure, turn one nipple a quarter turn and see whether the rim moved the way you expected. Undo it if not.

How to true a wheel laterally

1. Spin the wheel slowly. Watch the gap between the rim and the pointer. Find the spot where the rim comes closest or touches.
2. Find the centre of the wobble. Note the spokes in the middle of the section that rubs.
3. Adjust in pairs. If the rim rubs on the left, tighten the nearest right side spoke a quarter turn and loosen the nearest left side spoke a quarter turn.
4. Spread the change. For a long wobble, adjust two or three spokes on each side, with smaller turns on the outer spokes.
5. Spin and check. The gap should even out. Repeat with small turns.
6. Move the pointer closer. As the wheel improves, bring the pointer closer and repeat until the wobble is within a millimetre or two.

Work from the biggest wobble to the smallest. Never make one huge correction on a single spoke.

How to true a wheel radially

1. Set a pointer under the rim. Place it so it brushes the outer edge of the rim or the tyre bead area.
2. Spin and find the high spot. This is where the rim moves away from the hub, and the pointer touches.
3. Tighten spokes at the high spot. Tighten both left and right spokes in that area by the same small amount. This pulls the rim in without moving it sideways.
4. Find low spots. Where the rim dips towards the hub, loosen the spokes in that area evenly.
5. Recheck lateral true. Radial changes often affect side to side true, so go back and forth between the two.

Radial truing is slower and usually only needed for a visible hop. Small radial errors are common and often not noticeable when riding.

Checking dish

Dish is how centred the rim is between the hub's axle ends. A wheel can be perfectly round and straight but still sit off centre in the frame.

1. Check in the frame. Look at the gap between the rim and each fork leg or chain stay.
2. Flip the wheel. Turn the wheel around in the frame or stand. If the rim moves to the other side, the dish is off.
3. Correct it. Tighten all spokes on the side you want the rim to move towards by the same small amount, such as a quarter turn each. Then re-true.

A dishing tool makes this more accurate. BMX front hubs are normally symmetrical, so front wheels need little or no dish. Rear wheels can need some offset, depending on the hub's flange spacing. See cassette hub and front hub.

Spoke tension

A wheel with even tension stays true for longer. A wheel with very loose spokes will wobble again soon. A wheel with very tight spokes can crack the rim or pull nipples through.

• Squeeze pairs of parallel spokes on each side. They should feel similar.
• Pluck spokes on the same side. Similar tension gives a similar note.
• A tension meter gives real numbers. Follow the rim maker's recommended tension range if you have one.
• After truing, squeeze pairs of spokes firmly to settle them, then spin and check again.

If the spoke twists with the nipple, it can untwist later and undo your work. Turn slightly past the target, then back off a little.

When to stop

Stop truing and seek help if:

• The rim has a dent, kink, crack or flat spot.
• Spokes are bent, broken or badly rusted.
• Nipples are seized or rounding.
• The wheel will not come true without some spokes going very slack.

A badly bent rim is a safety risk. Replace it or have a bike shop rebuild the wheel. Check wheels regularly as part of your BMX maintenance basics routine.

Related

• Spokes
• Rims
• How to build a BMX bike from parts
• BMX tyre pressure