The ST4 is 87 Nm from memory but it is a steel swingarm, I think the M900 may be alloy - you should be able to google it if you don't have the handbook? Found this on Ducatimonster.org; Rear wheel nut 25x1.25 Nm ± 5% 83 Ft-lbs 61 Grease RETINAX - HDX 2