In cooperation with the U.S. Consumer Product Safety Commission, Shimano has voluntarily issued a safety recall on their PRO Atherton direct-mount bicycle handlebar stems sold from October 2009 to November 2010.
Some of these stems were supplied with 18mm-long bolts instead of 21mm bolts. These bolts, that hold the front plate of the stem to the body can pull out of the threads while the bike is being ridden, causing the rider to lose control of the bike and fall. Unfortunately, Shimano has received one report of an incident in which a rider fell injuring his torso and arm.
The recalled stem (photo above, left) consists of an aluminum body and front plate with four aluminum bolts. The body is black with red markings and has the word "PRO" in four places on the sides and the word "Atherton." The front plate is black and silver with the PRO logo in the center.
Stems with the following identification codes are being recalled: HH, HJ, HK, HL, IA, IC, ID, IE and IF. The identification code is located on the stem body where the handlebars are seated (photo above, left).
If you still have the package the stem came in, the model number PRSS0049 is found on the barcode sticker on the back of the package (photo above, right).