Jens I just pulled out my factory sheet that come with paw props they say to run for 033.049.06 all the same max 8x4 run in 7x4
min 5x3 they also list castor % running in 30%, fully run in 25%, BR (single BB) 20% , TBR 15% (racing and speed only) for long life I do not think I would go lower than 20% on the oil martin