How Wheel Balancing Works
A spinning machine measures where the wheel is heavy, and small lead, zinc or steel weights are added to the rim to bring it back to centre. The whole job takes 10 to 20 minutes for four wheels.
The three methods
UK garages use one of three approaches. Static is the historical method, dynamic is the standard, road force is the premium upgrade.
Static balance
LegacyThe wheel is placed on a single bearing or bubble fixture. Heavy spots fall to the bottom under gravity. A single weight on the opposite side corrects imbalance in one plane only. Inadequate for motorway speeds.
Dynamic balance
StandardThe wheel is mounted on a spinning machine that detects imbalance in two planes (inner and outer). Weights are added to both flanges of the rim. This is the standard service at every UK chain.
Road force balance
PremiumA loaded roller presses against the spinning tyre to simulate driving load. Detects force variations invisible to a free-spinning machine, and can match-mount tyres to the rim's high spot. Hunter GSP machines.
What happens when you drop the car off
Step by step, what the technician does in those 15 minutes.
- 01
Wheel removed.
Car raised on a two-post or four-post lift, lugs cracked off, wheel pulled clear.
- 02
Mounted on the balancer.
Cone or flange mount centres the wheel on the machine spindle. Operator types the wheel diameter, width and offset.
- 03
First spin.
The machine spins the wheel to around 200 rpm and reads vibration. The screen shows imbalance values for inner and outer planes.
- 04
Weights applied.
Operator hammers a clip-on weight onto the inner rim flange and sticks an adhesive weight inside the outer rim. Position guided by the machine's clock display.
- 05
Verify spin.
Second spin should read zero or near-zero on both planes. If not, weights are repositioned or added.
- 06
Wheel refitted.
Lugs torqued to manufacturer spec (typically 100 - 140 Nm).
Reading the machine
UK garages mostly run Hofmann GP series, Beissbarth ML or Hunter GSP machines. The screen shows two numbers: the weight needed in grams, and the clock position (12, 3, 6 or 9 o'clock relative to the valve stem).
A reading of 12g at 12 o'clock on the inner plane means the technician hammers a 12-gram clip-on weight onto the inner flange directly opposite the valve. The machine confirms the fix on the next spin.
Two-plane dynamic balance: clip-on inner, stick-on outer.
The weights
Wheel weights come in three varieties. Most cars get a mix of clip-on inner and stick-on outer.
Hammered onto the rim flange. Cheap, durable, visible. Standard for steel wheels.
Strip of weights stuck behind the rim spokes where they cannot be seen. Required for alloy wheels where a clip would scratch the finish.
Specialist weights tucked behind alloy spokes. Used when a stick-on strip would still be visible on a styled rim.
When standard balancing is not enough
If a vibration persists after a fresh dynamic balance, the escalation path is:
- Re-spin and reposition weights. Sometimes the first attempt isn't quite right.
- Road force balance. Detects tyre stiffness variation that free-spinning machines miss.
- Match mount. Rotate the tyre on the rim to align the tyre's high spot with the rim's low spot.
- Inspect the rim. A buckled rim cannot be balanced and needs straightening or replacement.
- Check wheel bearing. A worn bearing imitates imbalance but worsens with corner loading.