bottom bracket cartridge replacement Bottom Brackets have come a long way over the years. Instead of loose floating ball bearings packed inside of cups, bicycle frames of today accept a sealed bottom bracket [BB] cartridge. This enables you to get the lightest, smoothest cartridge available to upgrade your ride. Here's what you'll need to get your old one out and the new one in: 10mm allen wrench large adjustable wrench crank extractor tool bottom bracket cartridge tool grease [Park Tool's Poly 1000] clean lint-free rags Above: Chris King bottom Bracket Cartridges Step 1: Remove the cranks In order to get to the BB cartridge, we first need to remove the cranks. This requires the use of a crank arm extractor. There are a few different types of extractors on the market and you need to use the proper one for the type of cranks on your bike. The cranks shown in this guide are of the ISIS splined design and require a crank extractor with a large diameter tip. If your cranks are of square tapered design you will need to use a standard crank arm extractor with the standard sized tip. Remove the crank arm bolt using a 10mm allen wrench. Be sure to thread the tool all the way into the crank and use a wrench to snug it up before you attempt to extract the crank. Take care not to cross thread in this process. With the extractor threaded into the crank firmly, engage the center portion of the extractor by turning it clockwise. This will jack the crank off of the BB spindle. Once it is loose you can remove the crank by hand and unthread the extractor tool from the crank. Step 2: Remove the bottom bracket cartridge There are several types of BB cartridges on the market. The particular BB Cartridge on my track bike, shown below, is of the ISIS splined design. It requires an 8-notched tool to unthread the cartridge from the bottom bracket shell in the frame. BB's are generally made up of a two pieces: one having a threaded flange which is fixed to the cartrige and the other piece is a free threaded flange. Always remove the free flange first. My free flange is on the non-drive side of my frame. The nondrive side of the bottom bracket is threaded normally, so I turn the flange CCW to remove it. The drive-side of frames are reverse-threaded and so you will have to turn the flange CW to remove it. Once the cartridge is removed from the BB shell, you can wipe it off and set it asside. Step 3: Clean, grease & install the BB cartridge Now that the BB cartridge is removed, take a few minutes to inspect the frame's bottom bracket shell. You could find dirt and/or rust in there. Use a rag and/or tooth brush to clean the treads out as best as possible. Give the inside of the BB shell a fresh coat of grease. Grease the threads on both flanges of the BB cartridge you are about to install. If your BB cartridge includes a rubber o-ring, be sure to give it a coat of grease as well. Install the cartridge in the proper direction. The cartridge should have arrows and writing on its boddy which point to drive and non-drive side spindles. Using the proper tool, snug the cartridge firmly into the frame. Using the proper tooling, install the free flange into the other side of the bottom bracket and ensure that it is snugly threaded in place. Remember that the drive-side of the frame is reverse threaded! [lefty - tighty!] Step 4: reinstall the cranks Now that you've sucessfully installed your BB cartridge, its time to reinstall your cranks. Apply a liberal amount of grease to the BB cartridge spindle and press a crank onto it. Next apply grease to the 10mm crank arm bolts and thread them through the crank and into the spindle of the BB cartridge. Tightening this crank arm bolt will fully seat the crank onto the spindle. When installing the other crank on the other side of the bike, be sure to orient it 180 degrees out of phase of the other crank! Failure to do this is just plane embarassing!