Mount & coupling selector
Two quick tools: engine weight ÷ mounts matched against every Vetus load window, and a Bullflex lookup by propeller shaft diameter. We verify the final selection before anything ships.
Engine mount selector
Total engine + gearbox weight, divided across the mounts — matched to each Vetus mount's published load window.
The engine manual lists dry weight — add the gearbox if it's not included. Most installations use four mounts.
Bullflex coupling — by shaft size
Enter the propeller shaft diameter in millimetres (1" = 25.4 — and a 1" shaft is not a 25 mm shaft).
Selector FAQs
Why do mounts have a minimum load as well as a maximum?
Because the rubber has a working range. Vetus specifies that under the engine's static weight the element must compress at least a stated minimum — otherwise it's too hard for the engine and isolates nothing — and under weight plus torque reaction it must stay below the maximum. A mount that's 'safely oversized' is actually a worse mount.
Does engine power matter, or just weight?
Both. Weight sets the load window; power and drivetrain layout set how much propeller thrust and torque reaction the mounts must control, which is a stiffness question. The HY family (roughly 30–125 kW) and LMX family (roughly 70–350 kW) carry high fore-and-aft stiffness — up to 7× vertical on the LMX — precisely so thrust doesn't rock the engine.
Should all four mounts be the same model?
Usually, but not always — some installations carry more weight on the gearbox end, and the correct answer can be a stiffer pair at the back. That's a confirm-with-us case: send the engine model and weight distribution if you know it, and we'll check it against the Vetus tables.
How do I size the Bullflex if I don't know my engine's torque?
Start from the shaft — the lookup shows which sizes have a bore for your diameter — then we verify torque capacity from the engine and gearbox models. The coupling's published ratings (to DIN 6270B) need the gearbox reduction factored in, which is exactly the check we run before quoting.