Gates Carbon Drive CDX Front Sprocket – 4-bolt, 104 mm BCD - 55T
The Gates Carbon Drive CDX Front Sprocket – 4-bolt, 104 mm BCD is the front sprocket of the strongest Gates line: black, hard-anodised aluminium for belt-driven touring, mountain, trekking and gravel bikes. It bolts to cranks and spiders with a 104 mm bolt circle (BCD) and is available in 39, 42, 46, 50 and 55 teeth.
Why choose the CDX front sprocket?
Built for hard use. Hard-anodised 6061 aluminium is made to resist wear, and the sprocket belongs to the CDX line that Gates rates at up to 4× the life of a chain.
Strong enough for e-bikes. The CDX line is rated for hub motors and for mid-drive motors up to 120 Nm.
Sheds mud and snow. Gates’ Mud-Port tooth profile is designed to shed mud, dirt and snow.
Sizes. 39, 42, 46, 50 and 55 teeth, all with 11 mm pitch.
Which crank does it fit?
This sprocket fits cranks and spiders with a 4-bolt pattern on a 104 mm bolt circle diameter (BCD). Check the bolt count and the BCD on your crank or spider before you order. If you are not sure, send us a photo or the crank model and we will confirm the match.
Pairs with CDX, CDC and CDN belts
CDX, CDC and CDN are all CenterTrack parts with an 11 mm pitch, so this sprocket runs with belts from any of the three lines. For the full CDX strength use a CDX belt; each part keeps its own rating.
Technical data
| Property | Value |
|---|---|
| Gates line | CDX |
| Material | 6061 aluminium, hard-anodised surface (Gates Europe data) |
| Colour | Black |
| Mount | 4-bolt, 104 mm BCD |
| Tooth count | 39, 42, 46, 50 and 55 T |
| Pitch | 11 mm |
| Made for | City, mountain, trekking and gravel bikes |
How the Gates front sprockets compare
| CDX 4/5-bolt (this sprocket) | 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 bolt pattern do I need, 4-bolt 104 mm or 5-bolt 130 mm?
It is set by your crank or spider: look at the number of bolts and the diameter of the bolt circle. This sprocket is the 4-bolt, 104 mm BCD version; the other version is our CDX Front Sprocket with 5-bolt, 130 mm BCD.
Which tooth count should I choose?
It depends on your gearing and the rear sprocket, and the belt length follows from both. Gates offers a free Gearing and Center Distance Calculator in its Gates Sanity Check. Send us your frame, crank and hub and we will help you choose.
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 |
|---|---|---|
| 39T | 7898-00700 | XF1139B4AA |
| 42T | 7898-00703 | XF1142B4AA |
| 46T | 7898-00693 | XF1146B4AA |
| 50T | 7898-00694 | XF1150B4AA |
| 55T | 7898-00699 | XF1155B4AA |
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
