Road Bike Bottom Bracket Explained

There ll be an axle in there which turns in a pair of bearings.

Road bike bottom bracket explained. Road bike geometry explained. Your bottom bracket is that hollow bit at the bottom of the frame into which the bike s cranks fit to allow you to pedal. There are a few different widths. Bottom bracket standards explained road bike maintenance global cycling network.

Most road bikes that use a threaded bottom bracket measure 68mm wide and most cross country trail mountain bikes measure 73mm. Here then are the bottom bracket options available screw in bb s for threaded bottom bracket shells a quick word on threaded bottom bracket shell widths. Bikeradar s complete guide to bottom brackets. The standard on a road bike used to be 70mm.

Stack is the vertical distance from the centre of the bottom bracket to the mid point at the head tube. Multiple spacers are included in order to fit both sizes meaning if you see a bb for sale that says 68 73 it means it will fit both but it includes a couple spacers in the box to make it fit the 68 those spacers or fewer of them are not needed if the shell is 73mm wide. Perhaps partly due to these issues trek has in fact recently abandoned this bottom bracket standard on its domane endurance road bike platform for 2020 in favour of the t47 threaded standard. Briefly what happened back then was that companies went away from the tried and true threaded bottom bracket.

The bottom bracket is a bicycle component used to connect a bicycle s crankset to its frame allowing it to rotate independently of the frame itself. What size bottom bracket fits your bike. Instead they switched to a myriad of different press fit systems where the bottom bracket bearings are held in place in the frame s bottom bracket shell primarily by friction not threads. In old days it was easy.

How to remove fit a press fit bottom bracket on a road bike duration.