AndyMac Posted September 2, 2021 Share Posted September 2, 2021 (edited) Hi All I'm used to working on cars, so have a bit of mechanical knowledge - but I need some help in getting me started on getting the right parts for my bare frame Haro. So, I've measured up the internal diameter of the headset and bottom bracket. Headset is : 4inches tall (no cups) & the external diameter of the headset is : 1.5inches (1.4985) & the internal is 1.3inches (1.262) The bottom bracket is : 2.6inches (2.649) wide, with an external diameter of 2.2inches (2.2075) & and internal diameter of 2.0incoies (2.0165) So on the headset, I need cups and bearings, or I guess an intergrated version, but I've seen them listed as either 1inch or 1 1/8inch (1.125inches). How do I know which ones is the correct one to get ? Sorry if this is a common question/repost. Thanks Andy Edited September 2, 2021 by AndyMac Quote Link to comment Share on other sites More sharing options...
mr coasterbrake Posted September 3, 2021 Share Posted September 3, 2021 (edited) There are two measurements to consider: The diameter of the cup where it presses into the frame needs to be 32.5mm (that .5 can float a little, depending on the cup manufacturer). The second measurement is on the fork where the lower race presses on. That will be either 26.4 or 27.0mm depending on what the fork maker chose to use. **NOTE** old school BMX 1" headsets are different that most other 1" headsets (ie: road bike, MTB etc). The 32.5mm BMX size is not very common. anymore, sp make sure you get the correct thing. As for the bottom bracket, you want an "American" (sometimes also called a "pro") sized for the frame spec. Then you'll need to get one of those that is compatible with whatever style/brand of crank you want to use. Edited September 3, 2021 by mr coasterbrake additional info Quote Link to comment Share on other sites More sharing options...
