Steering head

How it works

The steering head is the axis around which the whole front end turns. The lower fork yoke carries a vertical tube, the steering stem, which passes through the frame's head tube and pivots on two bearings, one at the top and one at the bottom. These are usually tapered-roller bearings on modern bikes, sometimes ball bearings on older or smaller ones. Adjustment is delicate: too tight and steering is heavy and the bike can weave at low speed; too loose and play appears, with knocking under braking and sometimes a wobble at certain speeds. Over time and with water, the bearings get dented: the steering drops into a 'notch' in the straight-ahead position. A badly routed cable or hose can also restrict the handlebar's movement. Steering is a vital safety element; adjusting it and replacing the bearings needs proper tools.

Maintenance tips

• ✓Test for play: bike on a stand, front wheel lifted, push and pull the bottom of the fork; you should feel no knock.
• ✓Turn the bars lock to lock with the wheel lifted: they should pivot freely, with no tight spot or notch in the centre.
• ✓Check that cables and hoses don't stretch or catch when you turn the bars.
• ✓Have the steering bearings regreased or replaced at the interval in the manual.
• ✓Adjusting or replacing steering bearings is a job for a professional.