AEROZINE BSA30 Series: The Ultimate Power Transfer for MTB

Transform your ride with the perfect balance of friction-less rotation and rugged durability.

Why We Designed It This Way: The Philosophy of “Smooth Endurance”

Most riders face a frustrating trade-off: a bottom bracket that spins freely but dies in the mud, or one that is well-sealed but feels sluggish and heavy.

At AEROZINE, we refused to compromise.

The Low-Friction Challenge

The core mission of a bottom bracket is to turn your leg power into forward motion. To achieve ultra-smooth rotation, we must reduce resistance. However, reducing resistance usually means lighter seals, which allow water and dust to destroy the bearings.

Our Solution

We engineered a precision-fit sealing system that protects our high-grade bearings without creating “drag.” By using tight-tolerance CNC machining for the cups and specialized labyrinth seals, we’ve achieved a BB that spins like a racing component but survives like a workhorse. It’s smooth when you’re sprinting and sealed when you’re hub-deep in grit.

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What Makes AEROZINE Different?

While others focus on generic compatibility, we focus on the “Perfect Fit” Ecosystem. We don’t just sell a BB; we provide a high-performance interface for your 30mm spindle cranks on a standard BSA frame.

The “Must-Have” Upgrade: Industrial-Grade Bearings

We utilize Industrial-Grade Precision Bearings. Why? Because the torque generated by a human cyclist is significantly lower than what these bearings are rated for in industrial machinery.

• Result: It is nearly impossible to “break” these bearings through pedaling alone.

• Sustainability: With simple periodic cleaning and re-greasing, these bearings can last for years, outperforming “disposable” plastic alternatives.

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Is This Product For You?

✅ This is for you if:

• You are a Performance Seeker who hates feeling “mechanical drag” while climbing.

• You are a Durable Adventurer who rides in rain, mud, and dust but wants low maintenance.

• You value Precision Engineering and want a BB that won’t creak after three rides.

❌ This is NOT for you if:

• You prefer “disposable” parts that you throw away rather than maintain.

• You are looking for the absolute cheapest plastic option regardless of power loss.

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Maintenance & Installation: Built for Life

The secret to a lifelong Bottom Bracket is the bearing. Since we use industrial-strength steel, the hardware is incredibly robust. To keep your AEROZINE BB performing like day one:

1. Periodically clean the external seal area.

2. Re-apply high-quality grease to the bearing interface.

3. Ride hard. The more you ride, the more you’ll appreciate the smoothness.

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Technical Specifications

• Frame Type: BSA (English Threaded) 68/73mm

• Crank Spindle: 30mm (Compatible with AEROZINE and other 30mm spindle brands)

• Material: CNC Machined 6066 Aluminum Cups

• Bearings: High-Precision Industrial Grade

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Ready to Upgrade Your Drivetrain?

Recommended Accessory: Don’t forget the AEROZINE BB Installation Tool to ensure a perfect, scratch-free fit for your new BSA30 cups.

 

 

 

🚴‍♂️ Bottom Bracket Compatibility Cheat Sheet — Know What Fits What

Understanding your bike’s bottom bracket (BB) helps you choose the right crankset, axle (spindle), and bearing setup. Here’s a quick reference you can use before upgrading parts or buying upgrades:

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🔧 What Is a Bottom Bracket (BB)?

It’s the part of your frame where the crank spindle and bearings live. It connects the crankset to the frame and allows smooth pedaling rotation.

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📋 Common Bottom Bracket Standards

🔩 Threaded (BSA / English)

• Shell width: 68 mm / 73 mm

• Spindle compatibility: 24 mm, 30 mm & DUB with correct cups

• Great all-around choice, easy to service, widely supported.

🛠 Press-Fit BB86 / BB92

• Inner diameter: ~41 mm

• Designed mainly for 24 mm spindles

• Press-fit bearings in cups, common on road & MTB frames.

🔩 BB30

• Inner diameter: ~42 mm

• Cranks with 30 mm spindles press directly into the frame

• Very stiff & efficient but needs precise fit.

🧱 PF30

• Larger ID: ~46 mm

• Can fit 30 mm spindles and often adapted for other sizes with inserts

• Designed to combine stiffness and easier bearing fit.

🔩 BB90 / BB95

• Press-fit standards originally from Trek

• Designed for 24 mm spindles only — no 30 mm option.

🧰 T47 Threaded Press-Fit

• Threaded standard with larger ID (~47 mm)

• Supports 24 mm, 30 mm & others with proper cups

• Easier mechanical service than pure press-fit systems.

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🧠 Quick Compatibility Rules

🔹 24 mm spindles (Shimano Hollowtech II) are common in BB86/92 and BB90/95 designs.
🔹 30 mm spindles (BB30/PF30 and adapters) offer higher stiffness and modern performance orientation.
🔹 Threaded (BSA or T47) is easiest to service at home and avoids many press-fit creaking issues.

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📌 Quick Fit Checklist

1. Check your frame BB shell type:
   Threaded or Press-Fit?

2. Measure BB shell width & ID (e.g., 68 mm / 41 mm ID) to identify the standard.

3. Match spindle/crank diameter (24 mm or 30 mm) with a compatible BB or adapter.

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🔧 Common Upgrades & Notes

✨ You can often adapt standards using adapter kits — e.g., running 24 mm spindles in a BB30 with adapters — but it’s best to match the crank and BB as cleanly as possible for stiffness & longevity.

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🚩 Why It Matters

Choosing the right BB + crank/spindle combo ensures:
✔ Smooth pedaling feel
✔ Proper chainline & drivetrain efficiency
✔ Reduced noise and wear
✔ Easier service & longer life

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📩 Unsure what bottom bracket your bike has? Snap a pic of the BB shell (measure width & internal diameter) and send it to us — we’ll help you confirm compatibility!

PRODUCT  SPECIFICATION

Model No.：				BSA-68/73(30) -S
Frame Type				BSA 68/73
Material Bearing				#6805 bearings
Spindle diameter compatibl				Ø30mm
BB Cups				100% CNC-machined. L&R Aluminum alloy bearing cups with #6806 bearings
BB Shell				1 x plastic shell / 2 x  seal
Spacers				3 x 2.5mm (MTB)
BB Shell Width				D Thread 1.37”x24T / W68
				D Thread 1.37”x24T / W73
Color				#18 Red | #19 Orange | #20 Gold | #21 Green | # 22 Cobalt Green | #23 Blue |
				#24 Cobalt Blue | #25 Purple | #26 Black | #27 Silver
Weight				98g
warranty				2 years
Compatibility				Shimano BSA / fits 30mm cranks in BSA bottom bracket shells

 

 

bottom bracket
Frame system			D	W
Aerozine Name	Discipline	Spindel Ø	Shell inner Ø	Shell width	BB width	Cup length	Cup right	BB Spacer left	BB spacer right	bearing no
BSA-68/73(24) -S	MTB	24	BC 1.37″ x 24 tpi	68	96	10.2	10.2	2.5	5	Iron beads
BSA-68/73(24) -C	MTB	24	BC 1.37″ x 24 tpi	68	96	10.2	10.2	2.5	5	ceramic
BSA-68/73(24) -S	MTB	24	BC 1.37″ x 24 tpi	73	96	10.2	10.2	0	2.5	Iron beads
BSA-68/73(24) -C	MTB	24	BC 1.37″ x 24 tpi	73	96	10.2	10.2	0	2.5	ceramic
BSA-68(24) -S	ROAD	24	BC 1.37″ x 24 tpi	68	90	11	11	0	0	Iron beads
BSA-68(24) -C	ROAD	24	BC 1.37″ x 24 tpi	68	90	11	11	0	0	ceramic
BSA-ITA.(24) -S	ROAD	24	ITA.(M36mmx24T	70	90	10	10	0	0	Iron beads
BSA-ITA.(24) -C	ROAD	24	ITA.(M36mmx24T	70	90	10	10	0	0	ceramic
BSA-68/73(30) -S	MTB	30	BC 1.37″ x 24 tpi	68	96	10.2	10.2	2.5	5	Iron beads
BSA-68/73(30) -C	MTB	30	BC 1.37″ x 24 tpi	68	96	10.2	10.2	2.5	5	ceramic
BSA-68/73(30) -S	MTB	30	BC 1.37″ x 24 tpi	73	96	10.2	10.2	0	2.5	Iron beads
BSA-68/73(30) -C	MTB	30	BC 1.37″ x 24 tpi	73	96	10.2	10.2	0	2.5	ceramic
BSA-68(30) -S	ROAD	30	BC 1.37″ x 24 tpi	68	90	11	11	0	0	Iron beads
BSA-68(30) -C	ROAD	30	BC 1.37″ x 24 tpi	68	90	11	11	0	0	ceramic
BSA-ITA.(30) -S	ROAD	30	ITA.(M36mmx24T	70	90	10	10	0	0	Iron beads
BSA-ITA.(30) -C	ROAD	30	ITA.(M36mmx24T	70	90	10	10	0	0	ceramic

 

 

warranty

AEROZINE’s Warranty Exclusions:

The warranty does not cover damages or issues arising from:

• Shipping damage
• Misuse, impact, or improper installation (The product purchased does not match the specifications of the matching parts)
• Abnormal riding conditions
• Chemical exposure during handling, reassembly, or cleaning
• Premature wear, neglect, or failure of bearings, bushings, seals, or O-rings due to insufficient maintenance