Royce Union bicycles first appeared in the United States in the early 1970s. TLike other bicycles, handlebar height is adjusted by raising the handlebar stem, which connects the handlebar to the steering column. Depending on their vintage, Royce Union bikes will employ either a threaded or threadless handlebar stem. Threaded stems screw into the steering column. Threadless stems clamp onto the steering column.
Threaded Handlebar Stem - Locate the expander bolt at the top center of the stem. The bolt requires a 5 mm Allen key in order to adjust.
Use the 5 mm Allen key and turn the expander bolt counterclockwise. Two turns will be fine. Raise the stem to the required height. Be sure that at least 2 inches of stem extend down into the steering column.
Check that the stem and front wheel are perfectly in line. Turn the stem to the left or right as needed. Tighten the expander bolt, using the Allen wrench.
Threadless Handlebar Stem - Locate the two clamp bolts attaching the stem to the steering column. Use the 3 mm Allen key and turn each bolt clockwise to loosen. It isn't necessary to remove the bolts.
Locate the compression bolt on the top center of the stem. Use a 5 mm Allen wrench and turn the bolt clockwise to loosen.
Remove the compression bolt fully. Also remove the top cap through which the bolt passes. Lift the stem and handlebar assembly from the steering column.
Place a headset spacer onto the steering column. Headset spacers come in different widths. Choose one that raises your handlebars to the appropriate height.
Slip the stem back onto the steering column. Be sure that the top of the stem clears the steering column by about 1/8 inch as recommended by ParkTool.com. If the gap is much larger than this, use a narrower headset spacer.
Align the stem with the front wheel. Place the top cap back onto the head of the stem. Thread the compression bolt through the center of the cap, and tighten using the 5 mm Allen key.
Tighten the clamp bolts on the side of the stem, using the 3 mm Allen key.