All images are for reference only. Actual product color & size may vary.
Box®
Box Three Prime 9 X-Wide Rear Derailleur
Best for
race-focused BMX riders
Race class
Confirm by rider size
Fit checked before shipping · Mechanic support via WhatsApp · Authorized dealer sourcing
100% Secure Transaction
Live Stock
Inventory updated daily. Items in stock ship the next business day.
Fast Delivery
We use trusted couriers to make sure your order arrives safely and on time.
Secure Payments
100% secure transaction. We never share your information with third parties.
Satisfaction Guarantee
Every item is checked before shipment. Return within 10 business days if unsatisfied.
Preorder terms
Clear timing before you commit.
09 Sep 2026 target
Full payment or WhatsApp-assisted
Cancelable before supplier confirmation
~14 business days after order
Fit & geometry
Will this fit me?
Race class
Confirm by rider size
Rider height
Top tube
Check geometry/spec table before ordering
Wheel size
Material
Skill level
developing BMX racers
Setup context
Race-ready checks
Crank length
Gear ratio
Confirm chainring and cog setup
Brake type
Confirm brake standard
Pedal setup
Confirm included pedal/clipless preference
Track recommendation
Best for club racing and skill progression.
Next step
Still unsure?
Recommended upgrades
Complete the race setup
Gearing
Confirm chainring/cog ratio for your local track before checkout.
Contact points
Review pedals, grips, and saddle setup for gate-start confidence.
Protection
Pair the build with race helmet, gloves, and body protection.
Product info
About This Product
The Box Three Rear Derailleur simplifies the features found on the Prime 9 Box One and Two rear derailleurs making for a fully featured wallet friendly rear derailleur. Including a Limited Slip Clutch, Sealed bearing pulleys and a solid construction Box Three Rear derailleurs are compatible with 11-46 and 11-50t derailleurs making it one of the most versatile derailleur offerings for Prime 9. IMPORTANT NOTES Prime 9 Technology™ View Prime 9 Drivetrain Compatibility Manual How is the Ebike variant different? View Prime 9 Comparison Chart View Prime 9 E-Bike Comparison Chart Why Prime 9?
+COMPLETE YOUR SETUP
THIS ITEM
Box Three Prime 9 X-Wide Rear Derailleur
COMBINED TOTAL
Rp 3.502.992
Preorder each separately via WhatsApp for bundle deals
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Box Three Prime 9 X-Wide Rear Derailleur
Rp 943.027