SAE 8 Flywheel Standard – Coupling Fitment Guide

The SAE 8 flywheel standard defines the bolt circle, flange diameter, and bolt pattern used to connect diesel engines with couplings, hydraulic pumps, and power transmission systems. This international standard ensures that engine manufacturers and coupling producers can deliver fully compatible components with precise alignment and reliable torque transfer.

SAE 8 Dimensions (Catalogue Reference):

Outer diameter (Ø): 263.45 mm
Bolt pattern (Z): 6 × Ø10.5
Bolt circle (DO): Ø244.47 mm

Applications in Couplings:

The SAE 8 flywheel size is widely supported by coupling manufacturers. Typical OEM-approved solutions include:

KTR BoWex® FLE-PA – torsionally stiff flange couplings for diesel engine–pump connections.
KTR BoWex® Elastic – flexible couplings for applications requiring vibration damping.
CENTAFLEX-K – elastic couplings co-developed with engine OEMs for agricultural, marine, and construction machinery.

Why SAE Standards Matter:

The SAE 8 geometry is used by many leading engine producers, allowing direct installation of couplings without modification. The standardized dimensions prevent misalignment, minimize wear, and ensure a long service life of both coupling and engine drive train.

⚠️ Only original couplings manufactured to SAE standards guarantee safe operation. Genuine parts such as KTR BoWex FLE-PA (marked KTR-Kupplungstechnik, BoWex, FLE-PA, >PA6-GF25<, D-4440 Rheine) or CENTAFLEX K provide certified stiffness and durability. Copies may appear similar but often deviate in bolt accuracy, risking vibration, premature failure, or engine damage.