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Parts ranked by cup / bearing outside diameter

55.0 mm cup outside diameter, 54.9 to 54.95 mm head-tube bore
ZS55 headset standard has the highest cup / bearing outside diameter in the dataset, at 55.0 mm cup outside diameter, 54.9 to 54.95 mm head-tube bore.

Which part has the highest cup / bearing outside diameter?

ZS55 headset standard, at 55.0 mm cup outside diameter, 54.9 to 54.95 mm head-tube bore, tops the 8 parts we hold a published cup / bearing outside diameter for. The full ranking is below.

#PartsCup / bearing outside diameter
1ZS55 headset standard55.0 mm cup outside diameter, 54.9 to 54.95 mm head-tube bore
2IS52 headset standard51.8 to 52.0 mm bearing outside diameter
3EC49 headset standard49.6 to 49.7 mm cup outside diameter
4EC44 headset standard44.0 mm cup outside diameter, about 43.9 mm head-tube bore
5ZS44 headset standard44.0 mm cup outside diameter, 43.9 to 43.95 mm head-tube bore
6IS42 headset standard41.8 to 42.0 mm bearing outside diameter
7IS41 headset standard41.0 to 41.1 mm bearing outside diameter
8EC34 headset standard34.0 mm cup outside diameter, 33.8 to 33.95 mm head-tube bore

Data as of 2026-09-06.

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