EC49 headset standard (external cup vs IS52 headset standard (integrated: specs compared
Updated 05 September 2026.
3
specs differ
EC49 headset standard (external cup and IS52 headset standard (integrated differ on 3 specs: shis designation, cup / bearing outside diameter, crown race.
| Spec | EC49 headset standard (external cup | IS52 headset standard (integrated |
|---|---|---|
| SHIS designation | EC49 (external cup (EC)) | IS52 (integrated (IS)) |
| Cup / bearing outside diameter | 49.6 to 49.7 mm cup outside diameter | 51.8 to 52.0 mm bearing outside diameter |
| Steerer diameter | 38.1 mm (1 1/2 in) | 38.1 mm (1 1/2 in) |
| Crown race | 40.0 mm crown race seat | machined into the fork crown |
Questions and answers
How do EC49 headset standard (external cup and IS52 headset standard (integrated compare?
EC49 headset standard (external cup and IS52 headset standard (integrated differ on 3 specs: shis designation, cup / bearing outside diameter, crown race.