For years, the only tools available to remove the adjusting cap on Shimano’s Hollowtech II cranks were plastic. There are now a few metal tools on the market, but Park Tool’s Adjusting Cap Tool is the one we don’t hesitate to rely on.
Shimano’s Hollowtech II crank and bottom bracket design relies on the adjusting cap to preload the bearings. This cap rests against the left crankarm and is threaded into the bottom bracket spindle. While this cap only needs to be tightened enough to eliminate play in the system, it is often over tightened and/or seized in place. With the original plastic tools, removing this cap could be a pain. The force needed to remove a stuck cap will often round off the splines of the plastic tools; rendering them useless.
The Adjusting Cap Tool is shaped like a wing nut, which gives you plenty of leverage to remove a stuck cap. Should you come across a cap that is truly seized, you can insert a hex wrench into the center of the tool to create even more leverage. While this tool is very easy to use, Park Tool has a how-to video on their website just in case you need help.
The greatest benefit of this tool (its leverage) is also its main drawback. With the increased leverage, one must be careful not to over tighten the adjusting cap. Not only will that make the cap more difficult to remove later, but it will put unnecessary pressure on the bearings. This excess pressure will prevent your cranks from spinning smoothly and could lead to premature bearing wear.
GBL Last Word: Though not a tool most people will need at home, it’s a must for any bike shop. The hassle it avoids is worth the $12 asking price.
By Katie Arehart-Rose - Boulder, CO