Marantec 8030734, Curved Door Arm
The Marantec 8030734 curved door arm is part of the mechanical link between the garage door opener trolley and the garage door itself. When the opener runs, the trolley pulls or pushes through the door arm to move the door. The curved profile helps create the correct travel geometry on installations where a straight arm alone does not line up properly. On some Marantec manual references, one-piece doors specifically require replacing the factory straight arm with a curved arm before continuing installation. This part is also useful when the original curved arm is bent, missing, rusted, or damaged during a door repair. Because the door arm affects how force is transferred into the top door section, it should be installed with the proper door bracket, reinforcement if needed, and correct trolley pin connection.
Compatible With
- Select Marantec residential garage door operators using the matching door arm and trolley connection
- Marantec Synergy Solo, Synergy 260, Synergy 270, Synergy 280, Synergy 360, Synergy 370, and Synergy 380 applications where the door-arm geometry matches
- Marantec M4500, M4500e, M4700, M4700e, and M4900e style opener installations where the parts diagram calls for this curved arm
- Marantec M50 and M55 opener applications with compatible trolley and door bracket connection
- Marantec Q7500, Q7700, and Q7900 style applications where the door arm setup matches
- Mac-Lift / Marantec ML-2005, ML-2007, EX-2005, and EX-2007 references where the original arm style matches
- One-piece door installations where the Marantec manual requires a curved door arm
- Private-label Marantec-built openers only when the trolley pin, door bracket, and arm geometry match
Features & Specifications
| Manufacturer | Marantec |
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| Product Type | Curved door arm |
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| Part Number | 8030734 |
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| Application | Connects garage door opener trolley to door bracket |
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| Compatible Operator Type | Residential Marantec belt or chain rail garage door openers |
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| Door Type | Sectional or one-piece applications where curved arm geometry is required |
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| Notes | Match original arm style and installation diagram |
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Also Known As / Related Part Numbers
- 8030734
- MAR-8030734
- Marantec 8030734
- Curved door arm
- Marantec curved garage door arm
- Curved arm for Marantec opener
- One-piece door curved arm
Technician Note
A curved door arm should not be selected only by brand name. Compare the original arm shape, trolley pin connection, door bracket hole pattern, and the door type shown in the opener manual.
Before Ordering
- Confirm whether the original installation used a curved arm, straight arm, or a combination of both.
- Verify the opener trolley and door bracket connection points are not worn or damaged.
- Check the top door section for cracking or flexing before reconnecting the opener.
- Confirm the garage door is balanced and moves freely by hand.
- Use the correct clevis pins, cotter pins, and reinforcement hardware when required.
Important Ordering Warnings
- A damaged or incorrect door arm can cause binding, reversal, or stress on the top section of the garage door.
- Do not operate the opener with a bent arm, loose door bracket, or cracked top door section.
Professional Advisory
If the door arm pulled out of the door or the top section is flexing, install the proper reinforcement bracket and have the door inspected before running the opener.
Product Questions & Answers
What does the Marantec 8030734 curved door arm do?
It connects the opener trolley to the garage door bracket and provides the correct curved pulling geometry for compatible Marantec installations.
Is this used on one-piece garage doors?
It may be required on one-piece door installations when the Marantec manual calls for a curved arm instead of the factory straight arm.
Will this fit every Marantec opener?
It fits many Marantec residential opener setups, but the trolley, door bracket, rail style, and original arm layout should be checked before ordering.
Can I replace a straight arm with this curved arm?
Only if the opener manual or the existing installation requires that geometry. Straight and curved arms are not always interchangeable.
What else should be checked during replacement?
Check the door bracket, top-section reinforcement, trolley pin, rail alignment, and door balance before operating the opener.
