Eventually, you will have to replace the bottom bracket on your bike. When it comes to buying a new bottom bracket, there are a few things you need to consider, such as what size you will need, and what is the best bottom bracket for your bike. There are many bike component manufacturers making quality bottom brackets. Here, we look at Shimano bottom brackets.

The bottom bracket on your bike connects your crankset to the rest of your bike and allows the crankset to rotate freely. The bottom bracket contains a spindle that attaches to the crankset and bearings, allowing the spindle and cranks to rotate. The chainrings and pedals are attached to the cranks, and the bike’s bottom bracket fits inside the bottom bracket shell, which connects your seat tube, down tube and your chain stays as part of the frame of your bike.

Bottom brackets typically come in three sizes, so before you purchase a new bottom bracket for your bike, you will need to know the right size. This will usually be stamped on your existing bottom bracket, but if it isn’t, you can measure the shell of the bottom bracket.

You’ll also need to know the length of the axle you need. You can easily measure your existing axle to find this out.

Now, that you know what you are after, let’s take a look at some of the bike bottom brackets available from Shimano.

The 4500 Tiagra BB Cups

This Shimano bottom bracket features outboard bearing cups for use with Shimano’s Tiagra FC4500, FC4503 and Compact FC4550 2-piece cap-free design chainsets. With the 4500 Tiagra, you get a smooth ride thanks to the minimal bearing interface. They are available in both British and Italian threads.

The Deore UN54 Bottom Bracket

This bottom bracket from Shimano is a good quality bottom bracket that is suitable for most traditional chainsets. The Deore UN54 features super-accurate bearings that provide a smoother operation and longer lasting durability. They also have hard-wearing sealed cartridge bottom bracket with a square tapered, lightweight hollow spindle.

The seals will keep out any dirt mud or water, making them maintenance free and you’ll also enjoy longer lasting bearings. And what’s more, they are easy to install, so you’ll have the job done in no time at all.

The 105 5600 Bottom Bracket Cups

These 5600 Bottom Bracket Cups are outboard bottom bracket bearing cups that are designed to be used with Shimano 105 FC5600 and FC5603 Hollowtech II chainsets.

They feature minimal bearing interface for smoother rolling and are available for either British or Italian threads.

The 6601 Ultegra SL bottom bracket

This Shimano bottom bracket is designed to be used with Shimano’s HollowTech II Ultegra SL cranksets. With minimal bearing interface they provide ultra smooth rolling and the sealed cups mean your bearings will stay dirt and water free which means they will last a long time and you won’t have to worry about maintenance.

You can buy your bottom brackets separately, or you can usually get them as part of a groupset. If you’re not sure of compatibility, you may be better of purchasing the whole groupset which will also include your cranksets.

Tags: bike bottom brackets, Bottom Brackets, shimano bottom brackets

This entry was posted on Wednesday, July 22nd, 2009 at 11:17 am and is filed under Bottom Brackets. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.