Technically,
Payload is 850 lbs. (including you, your wife, bike, tongue load, and other items packed in the truck).
Towing capacity is 3500 lbs.
Others on here have towed more with no problems, but technically... :rolleyez:
Per "06 specs:
Curb weight (lb.): 3725
Gross Vehicle Weight Rating (GVWR) (lb.): 4600
Payload [6] (lb.): 875
Tongue load (lb., standard/maximum): 350
Standard towing capacity (lb.) [7]: 3500
Maximum towing capacity (lb.) [7] [8]: 3500
Gross Combined Weight Rating (GCWR) (lb.) - (with Towing Package): NA
[6] Payload is the GVWR minus curb weight and includes weight of occupants, optional equipment and cargo, limited by weight distribution. Payload is not the Vehicle
Capacity Weight as defined by FMVSS 110, which will vary according to installed optional equipment.
[7] Before towing, confirm your vehicle and trailer are compatible, hooked up properly and you have any necessary additional equipment. Do not exceed any Weight Ratings
and follow all instructions and cautions from your trailer hitch manufacturer and Toyota vehicle Owner's Manual. The maximum amount you can tow depends on the total
weight of any cargo, occupants and optional equipment.
[8] Maximum towing capacity and tongue capacity require V6 engine with available Towing Package. See Owner's Manual for details.