A Somfy motor does not touch the tube it drives. Between the two sits a small set of parts, a crown and a drive and a bracket, and getting them wrong is the reason a correctly-sized motor still will not install. These parts are cheap, specific, and not interchangeable.
What each part does
- Crown, also called the adaptor ring, fits over the motor's non-drive end and centres the motor inside the tube. It does not transmit torque. It stops the motor rattling around inside the tube.
- Drive, or drive wheel, locks onto the motor's output and engages the inside profile of the tube. This is the part that actually turns the shade.
- Bracket mounts the motor head to the wall, ceiling or shade cassette, and holds the motor against the torque it produces.
- Idler supports the opposite end of the tube. It is not a motor part, but a tube will not run true without one.
Crown and drive are always bought as a matched pair for a specific tube. Somfy sells them that way, and mixing sizes across sets does not work.
Start from the tube, because the motor sets the minimum
Before anything else, know the tube's inside diameter. Every Somfy motor publishes a minimum, and no accessory gets round it.
| Platform | Example part | Min tube ID | Head type |
|---|---|---|---|
| Sonesse 30 | 1241142 | 1.13 in | — |
| Sonesse 40 / 400 series | 1240380 | 1.46 in | Round |
| Sonesse 50 / LT50 | 1001809 | 1.85 in | Star |
| Sonesse ULTRA 50 DC | 1134023 | 1.85 in | Square |
| LT50 exterior | 1043423 | 1.85 in | Star |
| LT60 | 1164261 | 2.37 in | Star |
Sources: Somfy's product records for 1241142, 1240380, 1001809, 1134023, 1043423 and 1164261.
Three head types, not two
This is where most bracket orders go wrong. Somfy publishes three head types, and the bracket has to match the head, not the motor family or the torque rating.
- Star. A splined head that keys into a star bracket. The most common configuration, used across LT50, LT60 and the standard Sonesse 50 motors.
- Round. A smooth cylindrical head. The Sonesse 40 404S2 uses one, so a star bracket is wrong for it even though it is a mainstream interior motor.
- Square. Used on the Sonesse ULTRA 50 DC motors such as the 504A8. A star bracket will not hold one. This is the single most expensive mistake in this category, because the ULTRA is a premium motor and the bracket looks like it should fit.
Head type is a per-part specification. Two motors in the same family with the same torque can carry different heads, so read the head from the listing every time rather than inferring it.
Beyond the head, the bracket also has to suit the mounting: face mount, ceiling mount, or into a cassette with a fixed projection. Exterior cassette awnings usually dictate the bracket, because the cassette manufacturer sets the mounting geometry. Somfy's own LT50 Universal Motor Bracket (9410665) and LT50 Star Head Motor Bracket (9410651) cover most 500-series interior work.
Selecting a crown and drive set
A crown and drive set is chosen by two things, in this order.
1. The motor platform. LT50, LT60, LS40, Sonesse 30, Sonesse 40, Sonesse 50 and ST30 all have different output profiles. An LT50 set will not fit an LT60 motor. This is a hard compatibility boundary, not a tolerance.
A small number of parts are built for two platforms and say so in the name, such as the LT50/60 Octagonal 70mm Drive (9761002) and the 60mm Round LT50/60 Aluminum Drive Wheel (9012950). If the part name does not carry both platform numbers, treat it as platform-specific.
2. The exact tube. Not the nominal size, the exact tube. You need three facts about it:
- Profile. Round or profiled (keyed or grooved). A 2 in round tube and a 2 in profiled tube take different drives, because the drive engages the internal shape. This is why Somfy sells a 2 in hard clip drive and a 2 in soft clip drive as separate parts.
- Outside diameter. 1.5 in, 2 in, 2.5 in and so on.
- Wall thickness. A thicker wall means a smaller bore for the same outside diameter, and the crown has to fit the bore. This is what catches people who order from the outside diameter alone.
If you are matching an existing tube and cannot identify it, measure the inside diameter and photograph the internal profile. Those two facts identify almost any tube in common use.
Adaptor plates and cross-platform kits
Plenty of installations put a Somfy motor into a shade system built by somebody else, or reuse an existing headrail. Two kinds of part make that possible.
Adaptor plates mate a Somfy motor head to a bracket designed for another manufacturer's system. Plates are stocked for Rollease (including SkyLine and the R-series), ZMC, Acmeda and Louvolite brackets, such as the Motor Adaptor Plate for RollEase SkyLine and ZMC XL Series (9016378). If you are replacing a failed motor and keeping the brackets, an adaptor plate is usually what avoids rebuilding the headrail.
Cross-platform crown and drive kits let one platform's motor run in another's tube, such as the LS40 to LT50 Crown and Drive Adapter Kit (9013763). These solve a real problem but do not change the motor's minimum tube diameter, so check that first.
A worked order
For a typical interior roller shade on 2 in profiled tube with a Sonesse 506S2 RTS motor, the complete parts list is:
- The motor, Sonesse 506S2 RTS (1001809), which needs at least 1.85 in inside diameter
- An LT50 crown sized for that tube's bore
- An LT50 hard clip drive matching the tube profile
- A star-head LT50 bracket matching the mount
- An idler for the far end
- A power cable, a fast connector pigtail or SJTW cable with the right plug
- A control, an RTS remote or wall switch
Every motor listing on this site carries a compatibility panel naming the specific crowns, drives, brackets, tubes, cables and controls that complete that motor. That panel is built from Somfy's own documentation, so it is the fastest way to assemble a correct order.
Common questions
What is the difference between a crown and a drive?
The crown centres the motor's idle end inside the tube and carries no load. The drive locks onto the motor's output and transmits the torque that turns the shade. They are sold as a matched pair for one specific tube.
How do I know which bracket I need?
Read the head type from the motor's listing first. Star, round and square heads take different brackets, and torque rating tells you nothing about which head a motor has.
Will an LT50 crown fit an LT60 motor?
No. The platforms have different output profiles and different tube minimums, 1.85 in against 2.37 in. Only parts named LT50/60 fit both.
Can I use a Somfy motor in a Rollease or Acmeda headrail?
Usually yes, with an adaptor plate. Plates are stocked for Rollease SkyLine and R-series, ZMC, Acmeda and Louvolite brackets. Check the motor's minimum tube diameter separately, because a plate does not change it.
I have the tube but do not know what it is. What do I measure?
The inside diameter, and a photograph of the internal profile. Those two identify almost any tube in common use, and the inside diameter is what the crown and the motor minimum both work from.
Browse all motor accessories, start further back with How to Size a Somfy Shade Motor, or read the LT50 vs LT60 comparison if you are between platforms.
