Bought the wrong bottom bracket? Spent money on a part that doesn't fit?
It happens more often than you think. With names like BSA, BB30, PF92, and T47 floating around, it's easy to get confused.
But here's the good news: identifying your bottom bracket type is actually simple.
The Two-Question Method
Finding the right bottom bracket comes down to knowing:
Your frame type - What kind of bottom bracket shell does your bike have?
Your crankset spindle - What size is the axle connecting your cranks?
Think of the bottom bracket as an adapter between your frame and cranks. Know both sides, and you're done. Let's figure it out.
Step 1: Check Your Bottom Bracket Type (Frame)
Is it threaded or Press-Fit? Look inside your frame's bottom bracket shell (the hole where the BB goes). You're checking for one thing: threads.
Threaded Bottom Brackets
See threads inside the shell? Like the inside of a screw hole? You have a threaded bottom bracket. The cups screw into your frame.
Press-Fit Bottom Brackets
Smooth inside with no threads? You have a press-fit system. While standard cups are pressed directly into the frame, we define this standard with our CRODER TUBE-LOCK technology to ensure a secure, noise-free fit.
Common Frame Standards
Once you know if it's threaded or press-fit, here are the most common bottom bracket types:
Threaded Standards:
BSA (British Standard) - The most common
Width: 68mm (road) or 73mm (mountain bikes)
Found on most bikes from Trek, Giant, Specialized, Canyon
Also called "English threaded"
T47 - Modern threaded standard
Width: 86mm, 90mm, or 92mm
Larger threads (47mm diameter) for extra stiffness
Increasingly popular on high-end bikes
ITA (Italian) - Less common
Width: 70mm
Mostly on classic Italian bikes
Press-Fit Standards:
BB86/BB92 - Most common press-fit
Shell diameter: 41mm
Width: 86.5mm (road) or 92mm (mountain)
Works with 24mm or 30mm spindles
BB30 - For 30mm spindles
Shell diameter: 42mm
Width: 73mm
Bearings pressed directly into frame
PF30 - For 30mm spindles
Shell diameter: 46mm
Width: 73mm
Bearings in plastic cups
BB386 - Wide press-fit
Shell diameter: 46mm
Width: 86.5mm
Works with 30mm spindles
➜ Not Sure Which One You Have?
Measure it:
Shell width: Measure from one side of the frame to the other
Shell diameter: Measure the inside diameter of the hole
Or check:
Your bike's manual
The manufacturer's website
Your old bottom bracket (if you removed it)
Step 2: Check Your Crankset Spindle
The spindle (axle) is the rod connecting your left and right cranks. There are three common sizes:
24mm - Shimano Hollowtech II
The most universal standard. Found on: Most Shimano groups (105, Ultegra, Dura-Ace, Deore, XT, XTR), SRAM GXP cranks, FSA MegaExo, Race Face X-Type. How to identify: If you have Shimano cranks, it's probably 24mm.
29mm - SRAM DUB
SRAM's unified standard (introduced around 2018). Found on: Newer SRAM road groups (Force, Red from 2018+), Newer SRAM mountain groups (GX, X01, XX1 from 2018+). How to identify: Look for "DUB" printed on the crank arm or spindle.
30mm Spindles
The larger, stiffer option. Found on: Rotor cranks, FSA (some models), Older SRAM (pre-DUB), Many high-end cranks. How to identify: The spindle will be noticeably thicker.
💡 Pro tip
Most cranks have the spindle size printed on the crank arm. Can't find it? Use a caliper to measure.
Quick Compatibility Chart
Now that you know your frame and spindle, here's how they match:
