Align the front wheel, forks and handlebar

Home mechanic (basic tools) · Time: 30 to 60 min (editorial estimate) (estimate)

After a small fall or a hard hit on a pothole, the fork legs can twist in their clamps or the handlebar can turn in its mounts. The bike then pulls to one side or the bar is not straight when the wheel is. This job lets the fork legs, axle and handlebar settle back into line. It does not straighten anything bent. Bent fork tubes, yokes or frames need a workshop.

Safety

• First check for bent parts: look along each fork tube, compare left and right leg heights in the clamps, and check the frame. If a tube or yoke is bent, do not ride and do not try to straighten it. See Inspect the frame after a crash.
• Support the bike firmly. You will loosen parts that hold the front wheel.
• Brake disc and pads must stay clean.

You need

• The torques for the axle, axle pinch bolts, fork clamp bolts and handlebar clamp bolts on your bike. K-Light 125 front axle nut: 75 to 88 N·m. The K-Light 125 manual gives two different values for its lower fork clamp bolts, so confirm those for your model; no clamp torque is given here.

Steps

1. With the bike on its wheels, stand in front and look: is the front wheel straight when the handlebar is straight? Note which way it is out.
2. Handlebar only crooked in its clamps: loosen the handlebar clamp bolts, set the bar square to the forks, and retighten evenly to the model torque. Rubber-mounted bars (as on the K-Light 125) may twist on their mounts; check the rubber is not torn.
3. Forks twisted: put the bike on its centre stand with the front wheel on the ground. Loosen the axle pinch bolts (if fitted), then the lower fork clamp bolts, then the upper clamp bolts, one leg at a time only a little.
4. Stand in front, hold the front wheel between your knees, and turn the handlebar until it is square with the wheel.
5. Tighten the upper and lower clamp bolts to the model torque while holding the wheel straight.
6. Loosen the axle nut (and pinch bolts), take the bike off the stand, hold the front brake and push down hard on the bars several times. This lets the legs settle parallel on the axle.
7. Tighten the axle nut to the model torque (K-Light 125: 75 to 88 N·m), then the pinch bolts.
8. Check wheels are in line: run a string or two straight edges along both sides of the rear tyre to the front tyre, with the front wheel straight. The front tyre should sit centrally between the lines. If not, check rear wheel alignment with the chain adjuster marks (Check and adjust chain slack).
9. Turn the bars lock to lock: cables must not pull and the steering must move freely.

Check your work

• Wheel and bar are straight together.
• Forks move smoothly when you push down with the brake on.
• The bike rolls straight with your hands lightly on the bars on a quiet flat road.

If it did not fix the problem

• Still pulls: Bike pulls to one side.
• Forks stiff or one leg tight: Front forks feel sticky or stiff.
• Will not line up at all: a bent part. Fork legs are twisted or uneven.

Reference values (K-Light 125)