A practical sizing guide for buyers who need a motor that can lift the shade safely, fit the tube, and pass sample approval without oversizing the whole system.
What This Page Helps You Decide
Roller blind motor sizing looks simple until the buyer compares several fabrics, tube diameters and bracket widths in one product family. The same shade width can require a different motor when the fabric is heavier, the tube radius changes, or side friction increases. A clean RFQ should describe the real blind system before asking for a motor price.
For OEM buyers, the goal is not to buy the largest motor that fits. The goal is to select a stable diameter and torque range that can cover planned shade sizes while keeping cost, noise, tube fit, battery runtime and service risk under control.
Fast procurement note
Use this page before asking for final price. A complete roller shade motor RFQ should connect application, size, tube, power, control, accessories and target market so Walter Motor can recommend a practical configuration.
How to Make the First Selection
This table gives a first-pass decision path. Final model selection should be confirmed with drawings, samples and the exact Walter motor configuration.
| Buyer Situation | Recommended Direction | Procurement Note |
|---|---|---|
| Small indoor roller shades | Start from 25mm motors such as WM25BR or WM25AW after tube ID and minimum width are checked. | Best when the tube is compact and the fabric load is modest. |
| Medium roller blinds or zebra blinds | Review 35mm motors such as YYGL35S or YYGL35R when more reserve is needed. | Useful for wider blinds where a 25mm motor is too close to its limit. |
| Heavy blinds or commercial shades | Review 45mm motors such as YYGL45S or YYGL45R only after tube and headbox space are confirmed. | Higher torque can help, but oversizing may create fit and cost problems. |
| Battery retrofit shades | Check load, tube ID, daily cycles and charging access before selecting a battery motor. | Runtime depends on real use, not only motor rating. |
What Buyers, Engineers and Fabricators Should Check
Start with fabric weight and finished shade size
Fabric weight should be converted into the actual load of the finished shade. Buyers should include the fabric, bottom rail, hem bar and any decorative or blackout layers. A zebra blind, solar screen and blackout roller shade with the same visible width may not need the same motor.
Width and height matter together. Width affects total fabric weight and tube deflection. Height affects travel distance and the changing roll diameter during operation. A tall blind may start with a larger roll diameter and finish on a smaller radius, changing the torque demand through the movement.
When the RFQ includes several sizes, provide the smallest, average and largest blind dimensions. Walter Motor can then recommend whether one motor family can cover the range or whether the program should use separate 25mm, 35mm and 45mm configurations.
Tube diameter changes the lifting radius
Torque is influenced by the effective radius of the roller tube and fabric roll. A larger tube can reduce fabric marking and improve visual quality, but it also changes the leverage seen by the motor. The full roll diameter at the upper position should be considered, especially on tall shades.
Tube inner diameter also decides whether the motor physically fits. A motor that looks correct on torque may still fail if the crown, drive wheel, motor head or charging port cannot fit the tube and bracket system.
For repeat production, buyers should define tube profile, wall thickness, crown adaptor and drive wheel as part of the approved sample file.
Friction and safety margin protect the order
Side channels, tight brackets, warped tubes and fabric rubbing can increase operating load. These are common reasons a sample works on a bench but struggles on site. A practical safety margin helps absorb normal installation variation.
Safety margin should be reasonable. Too little margin creates stalling and after-sales complaints. Too much margin may increase noise, current draw, motor size and cost. For battery shades, oversizing can also reduce the attractiveness of the product because charging expectations become harder to meet.
The best selection process is to test the complete blind assembly, not only the bare motor. Walter Motor can review drawings and samples before mass production so the motor, tube and accessories are approved as a system.
Preliminary Motor Sizing Calculation Block
Use this block to prepare a first-pass sizing request. It does not replace sample testing, but it gives Walter enough data to avoid guessing from shade width alone.
1. Finished shade load
Add fabric, bottom rail, hem bar, adhesive layers and any decorative parts. If several fabrics are planned, list the heaviest fabric and the common fabric separately.
2. Effective roll radius
Record tube OD and approximate full-roll diameter at the upper position. Larger roll radius can increase the torque needed at the start of travel.
3. Practical reserve
Allow for side friction, bracket tolerance, fabric rubbing and installation variation. The reserve should protect the order without forcing an oversized motor.
| Data field | Why it matters | Buyer note |
|---|---|---|
| Blind width and drop | Sets finished fabric area and travel distance. | Send smallest, common and largest sizes. |
| Fabric weight and bottom rail | Defines the real lifting load. | Use grams per square meter plus bottom rail weight. |
| Tube ID, OD and profile | Controls motor fit and lifting radius. | Attach drawings or photos for non-standard tubes. |
| Side channel or fascia | Can add friction or clearance limits. | Flag blackout channels, cassette systems and tight brackets. |
| Daily cycles and room type | Influences heat, battery runtime and noise expectations. | Separate residential, hotel, office and commercial use. |
Avoid These Before Sample Approval
- Selecting only by shade width without fabric weight.
- Ignoring tube diameter and changing roll diameter.
- Using the same motor for every SKU when the size range is too wide.
- Oversizing a battery shade and then receiving runtime complaints.
- Approving samples without the final crown, drive wheel and bracket.
Recommended Procurement Path
Send Walter Motor the fabric weight, finished blind width and height, tube ID and OD, tube profile, bottom rail weight, power preference and control method. For early RFQ work, 25mm, 35mm and 45mm should be treated as starting points, then confirmed by the real shade structure and sample test.
Data to Send Before Quotation
Copy these points into your inquiry so the motor, control method and accessory set can be checked together.
- Finished blind width and drop, including the largest and smallest sizes.
- Fabric type, fabric weight and bottom rail weight.
- Tube inner diameter, outer diameter, profile and wall thickness.
- Expected daily cycles and room type.
- Power preference: battery, solar charging, DC or AC.
- Control method: switch, RF remote, receiver, smart bridge or smart protocol.
- Target market, certification needs and expected order quantity.
Continue the Buying Path
Frequently Asked Questions
How do I estimate roller shade motor torque?
Start with finished shade weight, tube radius, fabric roll diameter, friction and safety margin. For OEM production, confirm the calculation with a sample assembly before batch order.
Is a 25mm motor enough for roller blinds?
A 25mm motor can be suitable for compact indoor roller shades when torque, tube ID and minimum width fit. Wider or heavier blinds may need a 35mm or 45mm motor.
Should I choose the highest torque motor available?
No. Oversizing can increase cost, noise and fit problems. The correct motor should provide enough reserve without making the shade harder to manufacture or maintain.
What data should I send before quotation?
Send fabric weight, blind width and drop, tube ID and OD, tube profile, bottom rail weight, power type, control method, target market and quantity.
Can Walter Motor help check motor size?
Yes. Walter Motor can review the shade data and recommend a motor family, accessory set and sample configuration for buyer confirmation.
Send your roller blind motor data to Walter Motor
Include shade size, fabric weight, tube details, power preference, control method, accessories, target market and quantity. Walter can help check model selection before sample or batch order.