Bicycle handlebar or saddle wobbling

The cause is usually an insufficiently tightened clamp or an incorrect seatpost diameter. Tighten the bolts on the handlebar clamp and stem with the appropriate hex key to the torque printed on the component (usually 4–6 Nm) – not sure about torque? Use a torque wrench; carbon parts will crack otherwise. Check the saddle clamp: the seatpost must be inserted at least as far as the MIN marking inside the frame tube. Grease on contact surfaces (not oil) prevents creaking. Never overtighten aluminium clamps – replace immediately if cracked or severely deformed, as failure can cause a fall.