Welcome to our Ask a Mechanic column where our expert mechanic Daniel Slusser answers your bike maintenance questions. If you have a question for Daniel, please post it on our Facebook Wall or e-mail Daniel directly at firstname.lastname@example.org. The latest Art’s Cyclery/VeloNews Ask a Mechanic Video is shown first followed by an answer to a question regarding the BBRight bottom bracket standard.
Question: How do I know whether a frame has press-fit bbright or direct-fit bbright? Do you have pictures for comparison purposes? Thanks! From: James
Answer: The differences between the two standards can be seen in the BBRight technical drawing pdf. Direct fit has a 41.96mm diameter and PressFit has a 45.96mm diameter. The depth of the bore is different as well. Direct fit is 9.8mm and PressFit is 13mm. The difference between the two are pretty significant, so they should be easy enough to tell the difference, even without calipers. The other main difference between the two is that with the PressFit system the bearings sit in a plastic cup that is pressed into the frame. The Direct Fit standard presses the bearings directly into the frame.
So that you can see the differences between the two types of bearings, here is a link to the right bottom bracket bearings for PressFit BBRight. Here is a link to the right bearings for Direct Fit BBRight. We also have ceramic pressfit bearing options from Enduro and Wheels Manufacturing and a ceramic direct fit option from SRAM.
Daniel Slusser is a professional bicycle mechanic with over ten years of experience. He holds a bachelor’s degree in business administration from HSU and a master’s degree in history from Cal Poly. When he is not riding, wrenching, or writing he enjoys spending time with his wife and two children.