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See all results048404 · Application Note · Rev A · Feb 2011 · English · PDF, 4 pages, 0.5 MB
Lutron Sivoia QS Roller Shades Application Note: Cable Guided Shade Fabric Sag (048404)
Lutron's application note on fabric sag on angled cable-guided roller shades, and how to reduce or even it out.
Lutron 048404 Rev A (February 2011), Sivoia QS Roller Shades Application Note: Cable Guided Shade Fabric Sag. https://assets.lutron.com/a/documents/app note 404 - cable guided shade sag.pdf, via https://newwaykl.com/resources/lutron/roller-shades/sivoia-qs/lutron-sivoia-qs-roller-shades-application-note-cable-guided-shade-fabric-sag/
About document 048404
Lutron document 048-404, Rev A of 28 February 2011, is the cable-guided shade sag application note: what sets sag, four SCT configuration options, the two causes of uneven sag, cable alignment and tube leveling.
What note 048404 covers
Lutron document 048404 has these five sections. Each link opens the PDF at that page in a new tab.
- Overview: what causes sag on an angled shade, opens in a new tab page 1
- Reducing sag: four configuration options, opens in a new tab page 2
- Uneven sag: the two causes, opens in a new tab page 3
- Corrective action 1: cable alignment, opens in a new tab page 3
- Corrective action 2: leveling the shade tube, opens in a new tab page 4
Specifications in 048404
Lutron document 048404 prints 15 values in the groups the document uses, each with the document's unit. The page link beside each group opens the PDF where the group starts.
- Sag factors
- Shade height; fabric weight; bottom bar weight; shade angle
Reducing Sag
PDF page 2 of 048404, opens in a new tab- Where sag is shown
- SCT summary screen, during configuration
- Option 1
- Reduce Sag check box: adds bottom bar weight; not possible when drive torque is near capacity
- Option 2
- Oval bottom bar: takes more hem bar weights than the standard bottom bar, within drive capacity
- Option 3
- Lighter weight fabric
- Option 4
- Higher torque drive, with the oval bottom bar, for more bottom bar weight
Uneven Sag
PDF page 3 of 048404, opens in a new tab- Possible causes
- Cable alignment; unlevel shade mounting
Corrective Action #1
PDF pages 3 and 4 of 048404, opens in a new tab- Ideal cable geometry
- Upper cable width = lower cable width = fabric width
- Cable position
- In line with the fabric edges, parallel to each other, in a plane parallel to the window
- Check
- Clearance between cable and hem bar end cap loop over the full travel
- Correction
- Move the upper or lower cable anchors laterally
Corrective Action #2
PDF page 4 of 048404, opens in a new tab- Level tolerance
- 1/4 in over 10 ft (0.12 degrees)
- Instrument
- Digital or laser level; standard bubble level not precise enough
- Adjustment
- Raise the side with most sag, or lower the side with less
- Method
- Shim the brackets, or use the bracket level adjust feature if equipped
Installation walk-through for 048404
Lutron document 048404 gives six steps, in the document's order, after the tools and fixings it lists.
The clearance, the check and the warning under a step are the document's own.
Tools
- Digital level or laser level
Fixings
- Shims for the brackets, where the bracket has no level adjust
Read the sag figure during configuration
While the shade is being configured in the SCT, read the amount of sag shown on the summary screen. Where the figure needs to come down, choose one or more of the four reduction options in the next step.
Apply the sag reduction options
Choose one or more of the four options: tick Reduce Sag so weight is added to the bottom bar. Choose the oval bottom bar, which holds more hem bar weights than the standard bar within drive capacity.
Pick a lighter fabric, since heavier fabrics sag more. Or select a higher torque drive together with the oval bottom bar, so more weight can go on.
Warning: On larger shades the torque needed may already be near the drive's capacity, so Reduce Sag cannot add weight. Use option 3 or 4 instead.
Check the cable alignment (Corrective Action 1)
When an installed shade sags more on one side, check the cables before anything else. Run the shade from open to closed and watch where the hem bar end cap loop sits against each cable.
Cables line up with the fabric edges, parallel to each other and in a plane parallel to the window.
Clearance: Upper cable width equal to lower cable width equal to fabric width
Check: Cable clear of the end cap loop through the whole travel
Warning: A cable touching either edge of the loop adds drag on that side and increases sag as the shade lowers
Move the cable anchors
Where a cable touches the loop, shift the upper or lower cable anchors sideways. Keep shifting until the cable stays off the loop's sides for the shade's full travel.
Check: Upper cable width equal to lower cable width
Check the tube level (Corrective Action 2)
If uneven sag remains after adjusting the cables, check the shade tube for level with a digital or laser level. An angled cable-guided shade reacts far more to an unlevel tube than other shades do.
Clearance: Uneven sag may appear beyond 1/4 in out of level over 10 ft (0.12 degrees)
Warning: A standard bubble level does not have the precision needed
Level the shade tube
To even out the sag, raise the side with the most sag, or lower the side with less. Do it by shimming the brackets, or with the level adjust feature of the bracket system where it has one.
Check: Sag equal on both sides of the shade
Facts Lutron states in 048404
The values Lutron document 048404 states, as published:
- What sets sag
- Shade height, fabric weight, bottom bar weight and the angle of the shade
- Where sag is read
- On the summary screen of the SCT during configuration of the shade
- Reduce Sag check box
- Adds bottom bar weight, unless a larger shade's drive torque is already near capacity, when options 3 or 4 apply
- Option 2
- oval bottom bar: Takes more hem bar weights than the standard bottom bar, provided the drive can lift the extra weight
- Options 3 and 4
- A lighter fabric reduces sag, and a higher torque drive with the oval bottom bar allows more bottom bar weight
- Causes of uneven sag
- Cable alignment and unlevel shade mounting, with the cables checked first and the tube level only if uneven sag remains
- Ideal cable geometry
- Upper cable width, lower cable width and fabric width equal, cables parallel and in a plane parallel to the window
- Cable rub check
- Run open to closed, watching the hem bar end cap loop
- A touching cable drags that side and adds sag when lowering
- Move the upper or lower cable anchors sideways
- Sensitivity to an unlevel tube
- Much greater for an angled cable-guided shade than for other shades
- Levelness limit
- A tube more than 1/4 in over 10 ft (0.12 degrees) out of level may show uneven sag
- Instrument
- Digital or laser level, since a bubble level is not precise enough
- Leveling fix
- Raise the side with more sag or lower the other, by shimming the brackets or the bracket level adjust feature
Questions about document 048404
The answers come from Lutron document 048404 and New Way's record of it.
What is Lutron document 048-404?
Lutron's four-page Application Note 404, with the footer 048-404 REV A 02.28.11, on sag in angled cable-guided shades.
Which revision of 048404 is current?
Rev A, dated February 2011, is the revision Lutron publishes. New Way checked it against assets.lutron.com on 16 October 2026.
Which roller shades does 048404 cover?
Lutron Sivoia QS roller shades.
What determines how much an angled cable-guided shade sags?
Sag is the effect of gravity on an angled shade, per Lutron document 048-404. The amount depends on the shade height, fabric weight, bottom bar weight and shade angle.
Lutron document 048-404 shows the expected sag on the SCT summary screen during configuration.
How can sag be reduced when the shade is configured?
Lutron document 048-404 gives four options in the SCT.
- Tick Reduce Sag to add bottom bar weight
- Choose the oval bottom bar, which takes more hem bar weights
- Choose a lighter fabric, or a higher torque drive for more weight
Why does one side sag more, and what is checked first?
Lutron document 048-404 names two causes, misaligned cables and an unlevel shade mounting, and checks the cables first. Run the shade from open to closed while watching the hem bar end cap loop.
A cable touching the loop drags that side and increases sag. The cure is to move the upper or lower cable anchors sideways.
How level does the shade tube need to be?
Within 1/4 in over 10 ft (0.12 degrees), per Lutron document 048-404, or uneven sag may show. A digital or laser level is needed rather than a bubble level.
Lutron raises the side with more sag, or lowers the other, by shimming the brackets or the bracket level adjustment.
Does the fabric choice change the sag?
Lutron document 048-404 states that heavier fabrics sag more and that changing to a lighter fabric reduces sag. Fabric weight is one of four levers, beside Reduce Sag weight, the oval bottom bar and a higher torque drive.
Other Sivoia QS application notes
Application notes for the same Sivoia QS system:
| Document | Drive class | Revision | Date |
|---|---|---|---|
| 048863Roller Shades Application Note: Fabric Aesthetic Characteristics | Clutch, Commercial Contract Manual | A | May 2026 |
| 048562Application Note: Alkaline Battery Screening and Diagnosis | Roller 20 to 300 | A | Jul 2015 |
| Application Note: Blink Codes for Shades and Venetian Blinds | Roller 20 to 300 | ||
| 3683231Application Note: Care and Maintenance of Window Treatments | Clutch, Commercial Contract Manual, Roller 20 to 300 | C |
Documents used with 048404
Lutron document 048863, the roller shade fabric appearance application note, is the general fabric reference beside 048-404. Lutron document 048-404 assumes the shade is configured in the SCT, where the sag figure is read.
| Document | Type | Revision | Date |
|---|---|---|---|
| 085835Serena Open Roll Roller Shades Specification Submittal | Specification Submittal | A | Feb 2026 |
| 369612Pico Wireless Control Specification Submittal | Specification Submittal | Q | Jun 2025 |
| 0454114-Group RF Remote Control Installation Guide | Installation Guide | D | Jan 2015 |
| 045520Basic Wiring and Setup Installation Guide | Installation Guide | B | Nov 2016 |
| CAD Drawing: 30-Output Configurable Power Panel Enclosure (Power Modules Sold Separately), 35V Output, Elevation View (Front) | CAD Drawing | ||
| CAD Drawing: 30-Output Configurable Power Panel Enclosure (Power Modules Sold Separately), 35V Output, Plan View (Bottom) | CAD Drawing | ||
| 045000710 Output Power Panel Power Supply (12 V) Installation Guide | Installation Guide | A | Jul 2025 |
| 08533510-Output Smart Panel Specification Submittal | Specification Submittal | D | Apr 2020 |
| Roller Shades Wiring Diagram: Multiple Shades per Single QS Smart Panel | Wiring Diagram | ||
| Roller Shades Wiring Diagram: One Shade per Single QS Smart Panel | Wiring Diagram |
Revisions of 048404
This page always shows the revision Lutron publishes today. Lutron replaces the file in place and does not keep earlier revisions online.
| Revision | Date | Status |
|---|---|---|
| A | Feb 2011 | Current. The file on assets.lutron.com. Checked 16 Oct 2026. |
Not covered in 048404, and what to read next
Lutron document 048-404 does not cover installing the cables, anchor positions or the SCT itself, and prints no sag values.
- Cable installation: the fitted cable-guided shade's own installation guide
- Other fabric effects: 048863, the fabric appearance application note
Publisher and citation for document 048404
Lutron Electronics Co., Inc. publishes document 048404, Rev A, and serves it from assets.lutron.com. New Way hosts no copy and last checked the file there on 16 October 2026.
Lutron and Sivoia QS are trademarks of Lutron Electronics Co., Inc.
Reviewed by Edmond Hong, Technical Specialist, New Way.
Specifying Sivoia QS?
New Way supplies and installs Lutron Sivoia QS shading in Malaysia and Singapore. A New Way specifier can check your shade schedule and drawings before you submit.
The form opens with document 048404 filled in.
