The Formula DX-42 48H Rear BMX Hub is a classic, bombproof component engineered for mid-school BMX, freestyle, and heavy-duty street or park riding. Built to endure high impact, it boasts an ultra-robust 48-hole drilling configuration and a heavy-duty 14mm solid male steel axle with a traditional bolt-on setup to prevent wheel slippage in horizontal dropouts.
Key Features
Dual-Threaded Flip-Flop Design: Allows riders to run two different sizes of thread-on single-speed freewheels on a single hub shell.
Ultra-Durable Construction: Designed to withstand the rigors of freestyle and street riding.
Standard BC 1.37" × 24 TPI (Fits 16T and larger freewheels)
Non-Drive Side Threading
Metric M30 × 1 mm (Fits small M30-specific 13T, 14T, or 15T freewheels)
Over Locknut Dimension (O.L.D.)
Standard BMX rear spacing (110 mm)
Bearing Type
Traditional loose-ball / cup-and-cone mechanism
Understanding the Flip-Flop Mechanism
The defining feature of the DX-42 is its asymmetrical, dual-sided threading layout, offering maximum gearing versatility:
The Large Side (BC 1.37"):
Industry-standard thread size used by almost all standard single-speed freewheels.
Compatible with freewheels ranging from 16 teeth up to 22 teeth (e.g., ACS Claws or Shimano freewheels).
The Small Side (M30):
Features a smaller metric thread profile for compact freewheels.
Compatible with 13T, 14T, or 15T freewheels.
Why Use It?
Quickly alter your gear ratio depending on whether you are riding street, park, or dirt tracks.
By flipping the rear wheel around in the dropouts and moving your chain, you can alternate between a small gear (e.g., 13T) and a large gear (e.g., 16T) without needing a new hub.
Application & Compatibility
Rims: Must be paired strictly with a 48-hole BMX rim.
Freewheels: Does not feature an integrated cassette driver. Standard thread-on single-speed freewheels must be purchased separately.
Dropouts: Ensure your BMX frame has 14mm dropouts. Traditional race frames with 3/8" (10mm) slots will not accept this heavy-duty 14mm axle without modification.
Are you building a custom wheel and need a 48H BMX rim recommendation, or assistance calculating your gear ratio and chainring compatibility for the M30/BC1.37" freewheels?
