Bicycle Bottom Bracket Chaos: A Buying Guide to BSA, PF30, BB86, and T47

Introduction: The Most Confusing Standard in Cycling

Ask any bike shop mechanic “what gives you the biggest headache in this industry?” and there’s a good chance the answer will be “bottom bracket standards.”

Different brands, different model years, different bike lines — they can all use different BB standards. BSA, PF30, BB86, BB92, BB386, T47… just looking at this alphabet soup is enough to make your head spin.

Don’t worry. By the end of this article, you’ll at least know what BB standard your bike uses, and what to buy when it’s time for a replacement.

What Does a Bottom Bracket Actually Do?

The bottom bracket (BB) has a simple job:

1. Let the crankset rotate smoothly
2. Connect the crankset to the frame
3. Absorb all the force you put into pedaling

What a BB Is Made Of

• Spindle: the metal shaft connecting the left and right crank arms
• Bearings: allow the spindle to rotate smoothly
• Shell/cups: the structure fixed to the frame

A Complete Rundown of BB Standards

Threaded BBs

Standard	Shell Width	Threading	Spindle Diameter	Notable Brands
BSA (English)	68mm (road) / 73mm (MTB)	English 1.37"x24tpi	24mm	Shimano, most brands
ITA (Italian)	70mm	Italian 36x24tpi	24mm	Campagnolo, some Italian bikes
T47	68mm / 86mm	M47x1mm	30mm / 24mm	New standard, gaining ground

Press-Fit BBs

Standard	Shell Width	Shell Inner Diameter	Spindle Diameter	Notable Brands
BB86/BB92	86mm (road) / 92mm (MTB)	41mm	24mm	Championed by Shimano
PF30	68mm (road) / 73mm (MTB)	46mm	30mm	Cannondale, Cervelo
BB30	68mm (road) / 73mm (MTB)	42mm	30mm	Cannondale (discontinued)
PF86/PF92	86mm / 92mm	41mm	30mm	Less common
BB386	86mm	46mm	30mm	Pushed by FSA
BBRight	79mm	42mm	30mm	Cervelo

Threaded vs. Press-Fit

Why Did Press-Fit Even Show Up?

A few reasons press-fit BBs became popular:

1. Larger shell: can increase frame stiffness
2. Lighter: no threaded cups needed
3. Easier to manufacture: the frame doesn’t need to be tapped for threads
4. Larger spindle: a 30mm spindle is stiffer than a 24mm one

But Press-Fit Has Its Problems

Problem	Description
Creaking	The tolerance between the press-fit cups and the frame is prone to producing noise
Installation precision	Requires very high machining precision on the frame
Difficult to replace	Requires special tools
Standard chaos	Too many different variants

Industry Trend: Because press-fit systems have caused so many problems, more and more brands are going back to threaded designs (BSA or T47). T47 is the newest solution — it combines the reliability of threading with the large bore of press-fit systems.

BSA vs. PF30 vs. BB86 vs. T47 Comparison

Comparison	BSA	PF30	BB86	T47
Installation	Threaded, screws in	Press-fit	Press-fit	Threaded, screws in
Creaking risk	Low	High	Medium	Low
Difficulty to replace	Easy	Difficult	Moderate	Easy
Standard compatibility	Highest	Medium	High	Rising
Stiffness	Good	Good	Good	Best
Spindle options	24mm	30mm	24mm	24/30mm
Market trend	Stable	Declining	Stable	Rising

How to Identify Your BB Standard

Method One: Check the Frame Spec Sheet

The most accurate approach. Look up the BB standard in your frame’s manual or on the brand’s official website.

Method Two: Measure It Yourself

If you can’t find the documentation:

1. Measure the shell width: use calipers or a tape measure
2. Measure the shell’s inner diameter: use calipers
3. Check whether it’s threaded or press-fit: by feel or by eye
4. Compare against the tables above

Method Three: Bring the Old One to a Bike Shop

The simplest approach. Remove the old BB and take it to a shop to compare.

Common Brands and Their BB Standards

Brand	Model	Common BB Standard
Giant	TCR/Propel	BSA (newer models)
Giant	TCR (older models)	BB86
Merida	Scultura	BSA
Trek	Madone/Emonda	BB90 (Trek proprietary) / T47
Specialized	Tarmac SL7/SL8	BSA
Cannondale	SuperSix EVO	BB30/PF30
Cervelo	R5/S5	BBRight/T47
Canyon	Aeroad/Ultimate	PF86/BSA

Note: The same brand can use different BB standards across different model years. Always confirm the exact model and year of your bike.

BB Buying Recommendations

Shimano System

BB Standard	Recommended Model	Price
BSA 68mm	SM-BBR60 (Ultegra)	NT$500-800
BSA 68mm	SM-BB9000 (Dura-Ace)	NT$800-1,200
BB86	SM-BB72-41B	NT$500-800
PF30	Requires an adapter cup	NT$800-2,000

Third-Party Brands

Brand	Highlights	Price Range
CeramicSpeed	Ceramic bearings, lowest friction	NT$5,000-15,000
Wheels Manufacturing	Adapter solutions for various standards	NT$1,000-3,000
Chris King	Precision machining, extremely long lifespan	NT$4,000-8,000
Token	Taiwanese brand, great value for money	NT$500-2,000
Praxis	Fits multiple standards	NT$1,000-3,000

Adapter Solutions

If your frame is press-fit but you want to run a Shimano 24mm crankset:

• PF30 → Shimano 24mm: use a PF30 adapter cup (e.g. Wheels Mfg PF30-Shimano)
• BB30 → Shimano 24mm: use a BB30 adapter cup
• BB86 → Shimano 24mm: use a Shimano BB86-series BB directly

Maintaining Your BB

Dealing with Creaking

BB creaking is one of the most common noise complaints on bicycles:

Type	Cause	Fix
Threaded creaking	Loose BB cups	Re-torque and apply thread compound
Press-fit creaking	Poor fit between BB cups and frame	Replace and use retaining compound
Bearing noise	Worn bearings	Replace the BB
Crank noise	Loose crank bolts	Re-torque the crank

Replacement Interval

Type	Lifespan	Contributing Factors
Standard ball bearings	5,000-10,000km	Cleanliness, weather
Sealed bearings	10,000-20,000km	Quality varies widely
Ceramic bearings	20,000-50,000km	Requires regular maintenance

Conclusion

The chaos of BB standards is a long-running legacy problem of the cycling industry. The good news is the industry is gradually converging — BSA and T47 are becoming the mainstream choices. If you’re buying a new bike, choosing a frame that uses one of these two standards will make future maintenance and upgrades much easier.

If you need to replace your BB right now, the most important thing is: confirm your standard. Bring the old one to a bike shop, or check your frame’s manual. Using the wrong BB standard can, at best, simply fail to fit — and at worst, damage your frame.

Good luck finding the right one for you in the great BB standards war.

Related Reading

• BB (Bottom Bracket) Fully Explained: Standards, Maintenance, and Fixing Creaks
• Complete Guide to Bottom Bracket Removal, Installation, and Bearing Maintenance
• Bottom Bracket Installation Guide: BSA, PF30, BB86 Standards Explained
• T47 Bottom Bracket Deep Dive: The Ultimate Fix for Press-Fit Creaking