Gates Carbon Drive CDX Front Sprocket – Direct Mount, Alfine beltline - 55T
The Gates Carbon Drive CDX Front Sprocket – Direct Mount, Alfine beltline is the front sprocket for direct-mount cranks, made for belt-driven bikes with an Alfine rear hub. It is available in 46, 50 and 55 teeth, for the CDX belt line.
Why choose the Direct Mount front sprocket?
Direct mount. The sprocket mounts directly on the crank, with no spider needed – the same type of sprocket as on our CDX crank sets. 
Matched to your hub. Made for the Alfine beltline, so the front sprocket lines up with an Alfine rear hub. 
CDX belt line. Part of the CDX range, rated by Gates at up to 4× the life of a chain. 
46, 50 or 55 teeth. All with 11 mm pitch.
What is the beltline, and why does it matter?
The beltline is how far the belt runs from the centre of the frame. The front and rear sprocket must sit on the same beltline, or the belt runs crooked. This sprocket is made for the Alfine beltline: choose it when your rear hub is an Alfine.
Fits direct-mount cranks
This is the front sprocket for direct-mount cranks with the Alfine beltline, the same type that comes on our CDX crank sets (FSA Comet direct mount). It is the right replacement when a sprocket wears out: choose the same tooth count as your existing sprocket to keep your gearing and belt length.
Technical data
| Property | Value |
|---|---|
| Gates line | CDX |
| Mount | Direct mount (on the crank, no spider) |
| Beltline | Alfine |
| Tooth count | 46 T, 50 T, 55 T |
| Pitch | 11 mm |
How the Gates front sprockets compare
| CDX 4/5-bolt | CDC 4/5-bolt | CDX Pinion | CDX:Black Pinion | CDX Pinion SL | |
|---|---|---|---|---|---|
| Material | 6061 aluminium, hard-anodised | 6061 aluminium | Aerospace stainless steel | Chrome-moly steel, black zinc finish | 6061 aluminium |
| Colour | Black | Black | Silver | Black | Black |
| Fits | Cranks and spiders with 104 mm (4-bolt) or 130 mm (5-bolt) BCD | Cranks and spiders with 104 mm (4-bolt) or 130 mm (5-bolt) BCD | Pinion P- and C-line gearboxes, and the Pinion MGU from 39T | Pinion gearboxes | Pinion P- and C-line gearboxes |
| Made for | City, mountain, trekking and gravel | Commuting and mid-drive e-bikes up to 75 Nm | Mountain biking, adventure, bikepacking and trekking | City, mountain, trekking and gravel | Saving weight on a Pinion bike |
Frequently asked questions
Which beltline do I need, Rohloff or Alfine?
It depends on your rear hub. The Alfine version is made for the Alfine beltline; the other version is made for the Rohloff beltline. Tell us your hub and frame and we will confirm.
What do CDX, CDC and CDN mean?
They are Gates’ three belt-drive lines for bicycles: CDX (top of the range), CDC (mid-range) and CDN (entry level). Gates rates CDX for hub motors and mid-drive e-bike motors up to 120 Nm, CDC for mid-drive motors up to 75 Nm, and CDN for hub-motor e-bikes and casual riding.
Can I mix CDX, CDC and CDN parts?
CDX, CDC and CDN are all CenterTrack parts with an 11 mm pitch, so belts and sprockets from these lines fit together – each part keeps its own rating, and a drivetrain is only as strong as its weakest part. The older SideTrack (ST) range does not fit CenterTrack parts.
When should I replace a sprocket?
Check your sprockets from time to time. Worn teeth cause noise, tooth jump and faster wear on the belt, so replace the sprocket when the teeth are worn. A sprocket in good condition has even, undamaged teeth.
Sizes and Gates part numbers
Find your sprocket by its tooth count. The Gates article number and type designation are marked on the sprocket, so you can match a replacement exactly.
| Teeth | Gates article no. | Gates type designation |
|---|---|---|
| 46T | 7898-00439 | CT1146MBA-15.0 |
| 50T | 7898-00441 | CT1150MBA-15.0 |
| 55T | 7898-00443 | CT1155MBA-15.0 |
About Gates Carbon Drive
Gates Corporation has been a global leader in power transmission and belt drive technology since 1911. In 2007 it launched the first belt drive system for bicycles, and today more than 1,000 bike brands worldwide use Gates Carbon Drive, from city and trekking bikes to e-bikes, cargo and mountain bikes.
On the bike
