Kubota L3830GST, B7500HST, BX2660. Formerly: Case 480F LL, David Brown 880UE
I dont know about a B7500 with turfs, but our B7510 (with R4s) will easily outrun our BX2660 (which is equipped with Turf tires). Both have two range HST transmissions.
I have a B7800 with R4 tires that I drive to my office location 1/4 mile away top speed has recorded at between 12 & 13 mph using a car speedometer that was following me.