Introducing the Center Sleeve for Sram BSA-DUB Bottom Brackets
This message seems long overdue, but I am super stoked to introduce the center sleeve for Sram BSA-DUB bottom brackets.
For years (can you believe the DUB standard was introduced five years ago in 2018??) Kogel has stated that our bearings are properly sealed and do not need a spindle sleeve to protect them from the elements. Today I stand by that statement.
What is relatively new is the amount of unprotected hoses and wires that run freely through the inside of a frame. It seems only a few years ago that bikes had cables for braking and shifting. These cables always needed to be under tension so they would not interfere with the crank spindle. Each frame would have internal or external guides.
The current frame designs rely on hydraulic hoses and electronic wires for shifting and braking and often the designers will let the cables free float through the frame. Maybe with a rubber tube around the brake hose to dampen the sound of the hoses slapping against the inside of the down tube.
In past years, bottom bracket shells were bonded inside the frame and consisted either of a solid tube between the left and right side of the bottom bracket or a solid tube with some holes cut in them. In both cases mechanics had to do some serious finger gymnastics to route the internals. I don’t blame any designer for getting rid of the center tube to create more space inside the frame for routing.
The downside of getting rid of the solid center tube in the BB shell is that now any unprotected internal wires or hoses are free to rest on the crank spindle.
It took Kogel a while to design the center sleeve for BSA-DUB since the fit in a threaded frame is tight! For reference: the internal diameter of our BSA cups in 30.5mm, which leaves only .25mm on each side if you are using a 30mm crank spindle. For DUB spindles, that is only .75mm. Not a lot of room for an additional plastic tube.
We had to do some re-machining on the cups to create the extra space. As a result the BSA30 and BSA-DUB bottom brackets no longer share the same cups. The first batch of sleeves are 3D printed and I’m happy with the result. We will have to test if the volume justifies making these parts through injection molding. We will see. For now I’m happy to introduce the Center Sleeve for BSA-DUB.
Enjoy the ride!
In the picture below, look at that brake hose finding its way over the crank spindle and into the chain stay! The center sleeve is an absolute necessity for this frame.