Unitas 550 – interchangeable spare parts

Unitas (UT) 550 movement

Which spare parts fit the Unitas 550 movement? For every part you can see which other calibers use the same part according to the original interchangeability list.

27Parts with interchange data

25Calibers sharing parts

Note: We have compiled this overview to the best of our knowledge and belief, based on the original interchangeability lists of Unitas (UT) and the original spare-part labels. All information has been carefully checked but is provided without guarantee. Please verify the interchangeability yourself before fitting, especially the height, diameter and execution of the part.

🔧 Interchangeable parts

Part no.	Description	Also fits
182ISO 20.030	Barrel and cover	Unitas 190 Unitas 540
195ISO 20.060	Barrel arbor	Unitas 540
206ISO 30.015	Center wheel	Unitas 540
210ISO 30.025	Third wheel	Unitas 540
260ISO 31.041	Minute wheel	Unitas 540
301ISO 40.301	Regulator for flat hairspring	Unitas 540
311ISO 70.800	Upper cap jewel with end-piece	Unitas 190 Unitas 200 Unitas 200N Unitas 201 Unitas 201N Unitas 540 Unitas 580
330ISO 70.801	Lower cap jewel with end-piece	Unitas 540
336ISO 70.806	Upper cap-jewel with end-piece, for escape wheel	Unitas 540 Unitas 580
346ISO 70.807	Lower cap jewel with end-piece, f. esc. wheel	Unitas 540
401ISO 51.010	Winding stem	Unitas 190 Unitas 540
407ISO 31.121	Clutch wheel	Unitas 540
410ISO 31.120	Winding pinion	Unitas 190 Unitas 540 Unitas 580
415ISO 31.020	Ratchet wheel	Unitas 540 Unitas 580
420ISO 31.023	Crown wheel	Unitas 540
422ISO 81.067	Crown wheel ring	Unitas 190 Unitas 510 Unitas 520 Unitas 521 Unitas 540 Unitas 580
425ISO 51.120	Click	Unitas 540 Unitas 580 Unitas 630 Unitas 6360 Unitas 6365 Unitas 6365N Unitas 6470 Unitas 6475 Unitas 6476 Unitas 6480 Unitas 6480N Unitas 6485 Unitas 6485N Unitas 6486 Unitas 6486N Unitas 6487 Unitas 6488
430ISO 61.080	Click spring	Unitas 540 Unitas 580
435ISO 51.050	Yoke	Unitas 540
440ISO 61.100	Yoke spring	Unitas 540
443ISO 51.080	Setting lever	Unitas 540
443/5443ISO 51.080.06/.01	Setting lever	Unitas 540
445ISO 51.090	Setting lever spring	Unitas 540
450ISO 31.100	Setting wheel	Unitas 540
702ISO 30.040.12	Escape wheel and pinion, pivoted, for two end-pieces	Unitas 540
705ISO 30.040	Escape wheel and pinion	Unitas 540
710ISO 40.010	Jewelled pallet fork and stat	Unitas 540

Source: original interchangeability lists of Unitas (UT) (checked transcription) and checked original spare-part labels · as of 2026-10-28. Height / execution: the part fits only in this height or execution.

🌀 Matching mainspring

Mainspring dimensions for Unitas 550 (height × diameter × thickness × length) and matching mainspring in our shop:

Unitas 550: 1.35 × 7.0 × 0.08 × 240 mm (GR 3473)

🔗 Movements sharing the most parts

→ All calibers of Unitas (UT)

❓ Frequently asked questions

Which Unitas 550 spare parts also fit other movements?

For the Unitas 550, 27 part numbers are listed as interchangeable. Together they fit 25 other calibers – the table below shows which part fits which movement.

Which movements share the most parts with the Unitas 550?

The most shared parts: Unitas 540 (27 parts), Unitas 580 (7 parts), Unitas 190 (5 parts).

Which mainspring fits the Unitas 550?

According to the Générale Ressorts catalogue (height × diameter × thickness × length): 1.35 × 7.0 × 0.08 × 240 mm (GR 3473, hand-wound, normal end hook).