Crank Hub FIx

Details

>> No complex drilling of the crankshaft necessary!
>> One-piece crank stroke with friction disk
>> Force-fit connection to the crankshaft
>> Incl. new, original BMW bolt

The BMW S55 engines are known to suffer in some cases, even in original condition, from misaligned timing due to crankshaft sprocket rotation.
The reason for this is not loosened central screws, but the so-called phenomenon of torque overboost.
At low engine speeds, the torque actually acting on components increases due to vibrations of the combustion process.
Thus, an oscillating torque always acts on the crankshaft flange, which can eventually lead to slippage of the shaft-hub connection.

The reason why we deliberately decided against pins or other variants of fixation is that for optimum retention of the pins, they must be inserted with a fit in the crank hub and crankshaft.
Not only is it not possible to produce bores with such close tolerances due to the impractical crankshaft drilling process, but also, from a purely design point of view, it is not possible to create clearly defined fits in this application.

The result is that vibrations weaken the inaccurately fitted pins and, in the worst case, cause them to break off.

Instead, we equip our Crank Hub Fix with a so-called grip disc. This is a small plate coated with diamond particles, which increases the maximum transmissible torque of the shaft-hub connection by up to 4 times, as the diamond particles bite into the hub and crankshaft.

All without drilling the crankshaft.