How many wheels are on a tractor trailer?

If the tractor trailers has duels only. You have 18 weels. (10 on front 8 on back)

If the tractor trailers has super singles only, you got 10 wheels (6 wheels on the front and 4 on the back)

If the trailer has super singles only, you have 14 wheels, (tractor has 10 wheels and trailer has 4)

If your tractor has super singles only you looking at having, 14 wheels (6 wheels on the front 8 on the back)