Product review (3 stars): both through the hub and the roller surface and were as easily replaced, except for the missing nuts
My experience with this drum support roller kit involved a 20 year old Amana gas dryer that was making a thumping noise when in use.  Didn't affect the operation but bothered my wife. Enough said.
Research on the internet said the probable cure was to replace the drum rollers.  So, I bought this kit from Amazon two weeks ago and the first reason for only 3 stars.  It listed for $28.95.  Two weeks later, it's now listed for $9.72 plus shipping.  I know Amazon often changes partners but that doesn't ease the feeling that I got ripped off.  Strike one star.
My Amana's old wheels were thinner through the hub - by 1/4 inch - and required the changout of the shafts  (which were too short to mount the new wheel).  The new shafts also had different threads so using the old nuts was not possible and the image shows nuts for the shafts.  They were NOT included requiring me to go to the hardware store.  Strike another star.
What is interesting is that someone had issue with not enough fiber washers being included, my kit came with 7 fiber washers!
Other than the above, the kit did repair my dryer even though the wheels are "thicker", both through the hub and the roller surface and were as easily replaced, except for the missing nuts, as the YouTube video I watched.  Except...
Just an FYI.  The video showed a Whirpool electric dryer and my dryer is an Amana (made by Whirlpool) gas.  Obviously, the "guts" of Whirlpool dryers haven't changed much, if at all, for quite a while.  But the cabinets and electronic controlls must have.
The video showed how to release the two spring clips holding the top surface so it could be raised to access the screws holding the front panel.  On my Amana gas dryer, you need to remove the small access panel below the front panel (accesses the gas burner assembly - a nice design in my opinion) which then gives access to the screws holding the front panel which, in turn,  then gives access to the screws holding down the top.
Other than that, the video is perfect for showing how to replace the wheels.