Broken Bottom Bracket

[Manubrial]

After 6,000 or so touring miles, the bottom bracket on my Trek 920 broke. Does anyone know what is compatible for a replacement? If I were to choose to replace the entire drive train, what would be compatible? Finally, if I were to replace the drive train, should I go with a 1x for gravel?

[ReapThaWhirlwind]

Trek says that this model has a 73mm threaded bottom bracket.

Uncertain what crank your bike is currently housing, but if it's a square taper, you'll need something like BB-UN300 in 73mm. These also come in a number of axle widths. Which one you will need depends on how many chainrings the crank has. If it has three chainrings, the width is usually 126mm. If it's compact, it's usually 113mm or 116mm.

Trek website says this bike originally comes with a Sealed cartridge, GXP Type bottom bracket. If your bike still has the stock crank, a ProWheel forged 2-piece crank, then that's the bottom bracket you'll need to get instead.

[meamoantonio]

(10-08-2024, 01:43 AM)ReapThaWhirlwind Wrote:  Trek says that this model has a 73mm threaded bottom bracket.

Uncertain what crank your bike is currently housing, but if it's a square taper, you'll need something like BB-UN300 in 73mm. These also come in a number of axle widths. Which one you will need depends on how many chainrings the crank has. If it has three chainrings, the width is usually 126mm. If it's compact, it's usually 113mm or 116mm.

Trek website says this bike originally comes with a Sealed cartridge, GXP Type bottom bracket. If your bike still has the stock crank, a ProWheel forged 2-piece crank, then that's the bottom bracket you'll need to get instead.

this covers a lot of stuff you need to know OP, as a side note bottom brackets are usually very robust pieces of equipment you might just have to replace the bearings that are inside the bottom bracket shell so you don't have to spend as much. You can ask a mechanic to take out the bearing and you can check for yourself the code of the bearing so you can order a replacement.