Promax EX-1 Bottom Bracket
Best durable upgrade for competitive BMX and road cyclists.
A reliable, high-performance upgrade for standard 24mm spindle cranksets. The precision-sealed bearings and robust labyrinth seals ensure smooth, long-lasting rotation even in challenging conditions.
$54.99
at
Airpark Bike Co
More EX-1 options
Who it's for
- BMX racers seeking reliable performance in dusty or damp track environments
- Weight-conscious riders looking to optimize their racing setup for speed
- Cyclists wanting a straightforward upgrade for their existing 24mm crank systems
Who should skip it
- Home mechanics who prefer working with standard hex or crescent wrenches
- Aggressive freestyle riders requiring heavy-duty components for high-impact landings
- Aesthetic-focused owners who prioritize a pristine, showroom-quality look for their bike
Performance breakdown
Bearing Smoothness
Precision sealed bearings deliver a noticeably fluid and consistent pedal stroke.
Contamination Resistance
Double-labyrinth seals effectively block grit and moisture from entering the mechanism.
Build Durability
Cold-forged, CNC-machined alloy construction ensures long-term structural integrity under load.
Compatibility Range
Broad support for Shimano, FSA, and RaceFace standards simplifies drivetrain upgrades.
Weight Efficiency
Solid performance-to-weight ratio that won't weigh down your daily ride.
Installation Ease
Standard BSA threading makes this a straightforward swap for most frames.
Key Specs
Weight
102.9 grams
Material
Forged and CNC-machined alloy
Shell Width
68 mm and 73 mm
Spindle Diameter
24 mm
Spindle Interface
Shimano Hollowtech II, FSA MegaExo, RaceFace EXI
Bottom Bracket Standard
BSA/English threaded
Bearing Type
Sealed
Sealing Type
Double labyrinth seals
Color
Black
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