> For the complete documentation index, see [llms.txt](https://docs.revrobotics.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.revrobotics.com/duo-build/ftc-starter-kit-mecanum-drivetrain/drive-rail-assembly.md).

# Drive Rail Assembly

### Drive Rail Parts Required

| **PART NUMBER**                                                                                    | **DESCRIPTION**               | **QTY.** |
| -------------------------------------------------------------------------------------------------- | ----------------------------- | -------- |
| [REV-41-1762](https://www.revrobotics.com/rev-41-1762/)                                            | 45MM X 15MM C CHANNEL - 408MM | 2        |
| [REV-41-1687](https://www.revrobotics.com/rev-41-1687/)                                            | U CHANNEL ENDCAP              | 2        |
| [REV-41-1492](https://www.revrobotics.com/rev-41-1492/)                                            | M3 STANDOFF - 40MM            | 2        |
| [REV-41-1702](https://www.revrobotics.com/rev-41-1702/)                                            | TENSIONING BUSHING - 39MM     | 2        |
| [REV-41-1359](https://www.revrobotics.com/rev-41-1359/)                                            | M3 X 8MM HEX CAP SCREWS       | 24       |
| [REV-41-1361](https://www.revrobotics.com/rev-41-1361/)                                            | M3 NYLOC NUTS                 | 8        |
|                                                                                                    | **ASSEMBILIES**               |          |
| [ASSEMBLY 1](/duo-build/ftc-starter-kit-mecanum-drivetrain/90mm-single-sprocket-shaft-assembly.md) | 90MM SINGLE SPROCKET ASSEMBLY | 1        |
| [ASSEMBLY 2](/duo-build/ftc-starter-kit-mecanum-drivetrain/75mm-single-sprocket-shaft-assembly.md) | 75MM SINGLE SPROCKET ASSEMBLY | 1        |
| [ASSEMBLY 4](/duo-build/ftc-starter-kit-mecanum-drivetrain/drive-shaft-assembly.md)                | DRIVE SHAFT ASSEMBLY          | 1        |
| [ASSEMBLY 5](/duo-build/ftc-starter-kit-mecanum-drivetrain/ultraplanetary-gearbox-assembly.md)     | ULTRAPLANETARY ASSEMBLY       | 2        |
| [ASSEMBLY 6](/duo-build/ftc-starter-kit-mecanum-drivetrain/making-the-chain-links.md)              | 56 LINK #25 CHAIN LOOP\*      | 1        |

### Drive Rail Assembly Steps

|                                                                     |                                                                                                                                                                                                                                                                                                                                      |
| ------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| <img src="/files/-MG9vYAJQ3MYwnHo9_h8" alt="" data-size="original"> | <p>Attach an UltraPlanetary Assembly to a 45mm x 15mm C Channel - 408mm. Place M3 Screws and M3 Lock Nuts in the correct locations. Tighten until nuts are snug.</p><p></p><p><strong>Note:</strong> The Output Cartridge of the UltraPlanetary Gearbox lines up with the fourth large (9mm) hole from the end of the C Channel.</p> |
| <img src="/files/-MG9hU--PrMD6nyvl_VT" alt="" data-size="original"> | <p>Place M3 Screws and M3 Lock Nuts in the correct locations. Tighten until nuts are snug.</p><p></p><p><strong>Note:</strong> The Output Cartridge of the UltraPlanetary Gearbox lines up with the thirteenth large (9mm) hole from the end of the Channel.</p>                                                                     |
| <img src="/files/-MG9bt1R-BbzWWJn8_ub" alt="" data-size="original"> | Attach a U Channel End Cap to the Motor end of the C Channel. Add three Hex Cap Screws to hold it in place. Tighten the Hex Cap Screws.                                                                                                                                                                                              |
| <img src="/files/-MG9bD7ZRCJ3km_luo19" alt="" data-size="original"> | Attach a U Channel End Cap to the other end of the C Channel. Add three Hex Cap Screws to hold it in place. Tighten the Hex Cap Screws.                                                                                                                                                                                              |
| <img src="/files/-MG9Vc0JxLBVdjgUuXsZ" alt="" data-size="original"> | Align the Hex of the shaft with the UltraPlanetary Gearbox. Insert the Drive Shaft Assembly into the UltraPlanetary Female Hex output.                                                                                                                                                                                               |
| <img src="/files/-MG9YkcMjch4DoLMskj8" alt="" data-size="original"> | Remove the Shaft Collar, Mecanum Wheel, one 3mm Spacer, and the Through Bore Bearing – Long from the Drive Shaft Assembly.                                                                                                                                                                                                           |
| <img src="/files/-MEPGcq74Jag4HQTPJZb" alt="" data-size="original"> | Remove the Shaft Collar from the 75mm Single Sprocket Assembly. Set aside for use later.                                                                                                                                                                                                                                             |
| <img src="/files/-MG9TZHLkvcFRuyusMqf" alt="" data-size="original"> | Align the Hex of the shaft with the UltraPlanetary Gearbox. Insert the 75mm Single Sprocket Assembly into the UltraPlanetary Female Hex output as shown.                                                                                                                                                                             |
| <img src="/files/-MEPKZ1uuEHj8XuNDDOD" alt="" data-size="original"> | Remove the Shaft Collar from the 90mm Single Sprocket Assembly. Set aside for use later.                                                                                                                                                                                                                                             |
| <img src="/files/-MG9SqbFovv02jslmqfL" alt="" data-size="original"> | Insert the 90mm Single Sprocket Assembly, sprocket side toward the motor, into the fourth large hole from the non-Motor End Cap.                                                                                                                                                                                                     |
| <img src="/files/-MG986Z8x86Kf9I1u0rM" alt="" data-size="original"> | Add a Shaft Collar to the end of the shaft. Tighten down the set screw.                                                                                                                                                                                                                                                              |
| <img src="/files/-MG5hSCxB-YRwKccCfSJ" alt="" data-size="original"> | <p>Add two M3 Standoffs - 40MM along the C Channel for chain tension with M3 Hex Cap Screws. Add Tension Bushings onto each Standoff</p><p></p><p><strong>Note:</strong> See the next step for locations.</p>                                                                                                                        |
| <img src="/files/-MG97GRyCEG8A0F4xoxX" alt="" data-size="original"> | <p>Tighten down the Hex Cap screws once the Standoffs are in the correct locations towards the bottom of the slotted holes.</p><p></p><p><strong>Note:</strong> Screws should be tightened just enough to hold the standoffs in place. Chain tension is adjusted later in the drive rail construction.</p>                           |
| <img src="/files/-MG5gWoIx1anMftoAyLD" alt="" data-size="original"> | <p>Add the 56 Link Chain Loop to the Sprockets.</p><p></p><p><strong>Note:</strong> Keeping the Standoffs with Tensioning Bushings loose can help to get the chain loops on the Drive Rails.</p><p></p><p>If using the Mecanum Drivetrain Kit replace the chain link with the 120 Tooth Belt (REV-41-1800). </p>                     |
| <img src="/files/-MG5g-tfGUhvCxuIvMva" alt="" data-size="original"> | <p>Take a 45mm X 15mm C Channel – 408mm and seat the large holes on the bearings on each shaft.</p><p></p><p><strong>Note:</strong> Make sure the bearings are square and the Channel End Cap holes line up.</p>                                                                                                                     |
| <img src="/files/-MG5cPUHDhD_o6W6ewgk" alt="" data-size="original"> | Take eight Hex Cap Screws and secure the 45mm X 15mm C Channel – 408mm to the rest of the assembly. Screw into the End Caps and the Standoffs to keep the chain tensioned.                                                                                                                                                           |
| <img src="/files/-MG5bGbMKHfglJQfpkwO" alt="" data-size="original"> | <p><strong>DRIVE RAIL ASSEMBLY COMPLETE</strong></p><p>Repeat this step until you have two Drive Rail Assemblies.</p>                                                                                                                                                                                                                |


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