The newer, smaller wheels, have inserts that are removable for the large and small shafts. Are the old 4" wheel inserts removable, they seemed to be solvent welded?
I did find this, which seems to mean you can do it, but it’s difficult:
I’ve used that trick on all my robots in the past starting from Gateway, replacing the insides with the metal inserts. I believe it would work the same for the high strength shafts.
It’s actually very easy to do, but just time consuming. I haven’t done so in a while because all the wheels I find around the room now have that modification on them, or I use different sized wheels. Last time I did it was around Toss Up year, and I believe I just used a pair of needlenose pliers and a thin flathead to help pry stuff.
You want to make sure that you dont scuff up the plastic too much, otherwise it won’t look nice afterwards, and you might have some misalignment on the shaft.
Yes, it possible to take out the inserts of 4" or 5" wheels, but it is kind of hard.